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Original Investigation |

Relationships of Heart Disease Risk Factors to Exercise Quantity and Intensity FREE

Paul T. Williams, PhD
[+] Author Affiliations

From the Life Sciences Division, Lawrence Berkeley Laboratory, Berkeley, Calif.


Arch Intern Med. 1998;158(3):237-245. doi:10.1001/archinte.158.3.237.
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Objective:  To assess the relationships of exercise amount and exercise intensity to coronary heart disease risk factors measured cross-sectionally in runners.

Methods  Physician-supplied medical data were compared with subjects' reported average running amount (kilometers run per week) and running intensity during their best recent 10-km race (kilometers per hour) in 7059 male and 1837 female recreational runners. Ten-kilometer race velocity (kilometers per hour) is known to be related to exercise intensity during training.

Results  Men and women who ran faster (ie, at greater intensity) had lower blood pressures; triglyceride levels; ratios of total cholesterol to high-density lipoprotein cholesterol; body mass indexes (calculated as the weight in kilograms divided by the square of the height in meters); and circumferences of the waist, hips, and chest when adjusted for weekly running distance, age, consumption of alcohol, and diet. Relative to the effect of running distance, running velocity had a 13.3 times greater calculated effect on systolic blood pressure, a 2.8 times greater calculated effect on diastolic blood pressure, and a 4.7 times greater calculated effect on waist circumference in men, and a 5.7 times greater calculated effect on systolic blood pressure in women when adjusted. In contrast, running distance had a more than 6-fold greater calculated effect on adjusted plasma high-density lipoprotein cholesterol levels than running velocity in both sexes.

Conclusions  Exercising more intensely could improve coronary heart disease risk factor level beyond that achieved by exercise amount alone; however, proof of causality remains to be determined from clinical trials. Exercise intensity and amount may target specific coronary heart disease risk factors.

Figures in this Article

LONG-DISTANCE runners have higher concentrations of high-density lipoprotein (HDL) cholesterol and lower levels of low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure, and adiposity relative to sedentary individuals.15 Prior discussions of intensity have focused on comparing moderate (3-6 metabolic equivalents or 17-29 kJ/min) with vigorous physical activity (>6 metabolic equivalents or >29 kJ/min6,7) while largely neglecting the health effects of vigorous activity performed at different intensities. Running is classified as a vigorous exercise performed at different intensities1,2 depending in part on speed.

Individual differences in 10-km and marathon (42195 m) race performance times are principally caused by differences in the capacity to produce energy through oxidative pathways (maximum oxygen uptake) and the limitation in achieving this capacity due to the accumulation of metabolic by-products (blood lactate threshold). Accomplished runners can run 10-km race velocities requiring between 79% and 98% of maximum oxygen uptake811 and marathon race velocities requiring between 68% and 88% of maximum oxygen uptake.11 Nearly 30 years ago, running performance (velocity) was proposed as a field measurement of maximum oxygen uptake in epidemiological studies,12 yet its relation to coronary heart disease (CHD) risk factors has been scarcely reported1316 and never for large samples.

Much use has been made of the concordance between physical fitness and amount of physical activity. Treadmill fitness parameters (maximum oxygen uptake or work capacity) have been used to (1) validate differences in exercise amount in clinical trials,4,5 (2) validate physical activity questionnaires,7 (3) purportedly provide a less-subjective measure of physical activity than self-reported amounts,17 and (4) formulate government recommendations for exercise amount.6 Although related, physical fitness and physical activity amounts are different variables. Greater fitness often refers to a greater maximum oxygen uptake, which requires a greater efficiency of the oxygen transport system,18 whereas a higher weekly amount of physical activity requires that the energy costs of the activity be met.19 The physiological distinctions between being more physically fit and being more physically active are seldom exploited in studies of health.

This article examines the independent contributions of exercise amount and intensity (or fitness as measured by race performance) to CHD risk factor levels in 7059 male and 1837 female runners who participated in the National Runners' Health Study.1 The 1996 surgeon general's report on physical activity states that "people who can maintain a regular regimen of activity that is of longer duration or of more vigorous intensity are likely to derive greater benefit."7 In contrast, earlier government recommendations stated that "the health benefits of physical activity depend principally on the total amount of physical activity rather than intensity."6 A significant relationship of CHD risk factors to race performance (a variable reflective of usual training intensity2022) when adjusted for exercise amount would lend support to the surgeon general's more recent recommendations.7

The design and subject characteristics of the National Runners' Health Study are described elsewhere.1,2,23 The cohort received a 2-page questionnaire that was distributed nationally at races and to subscribers of the nation's largest running magazine (Runners' World). This questionnaire solicited information on demographics (sex, age, race, and years of education); running history (age when the participant began running at least 19 km per week, average weekly running distance, and best marathon and 10-km race times during the prior 5 years); weight history (highest and current weight, weight when the participant started running, lowest weight as a runner, and circumferences of the chest, waist, and hips); diet (vegetarianism and the current weekly intakes of alcohol, red meat, fish, fruit, vitamin C, vitamin E, and aspirin); current and past cigarette use; history of heart attacks and cancer; and medications taken for disorders of blood pressure, thyroid gland, cholesterol, or diabetes. Average number of kilometers run per week was computed by averaging the reported yearly distances of the preceding 5 years. Body mass index (BMI) was calculated as the weight in kilograms divided by the height in meters squared.

The questionnaire also requested permission to obtain measures of participants' height, weight, cholesterol, triglycerides, blood pressure, and resting heart rate from the runners' physicians. On the rare occasion that data from more than 1 clinic visit were provided by the physician, we used the values from the most recent clinical visit in which HDL cholesterol was measured. High-density lipoprotein cholesterol values were obtained from the medical records of 7059 male and 1837 female nonvegetarian, nonsmoking runners who were without a history of heart disease or cancer and who were not using medications that might affect lipoprotein levels. The 1002 males taking medications were added to the 7059 males not taking medications to calculate the percentage of men with hypertension. Hypertension was defined as a systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher, or use of medication for blood pressure control (untreated hypertension may be overestimated because it is based on readings from a single clinic visit).

Average number of kilometers run per week was computed by averaging the reported yearly distances during the preceding 5 years. The test-retest correlations for self-reported running distance per week (r=0.89; unpublished data from 110 runners who completed duplicate questionnaires several months apart, 1993) compare favorably with those reported for the Minnesota leisure time physical activity questionnaire24 and others.25,26 There is also a significant inverse relationship between reported running distance and resting heart rate,1,2 a measure commonly used to validate physical activity assessment, since bradycardia is a cardiac manifestation of aerobic conditioning. Consumption of alcohol, red meat, fruit, and fish was validated by correlating reported usual weekly intakes from the questionnaires with recorded actual intakes from 4-day food records. The 2 methods corresponded most strongly for alcohol intake (r=0.65) and moderately for red meat (r=0.46) and fruit (r=0.38). The weak correlation for consumption of fish presumably relates in part to infrequent intake (r=0.19).

Two approaches were used to validate questions on anthropometric measurements from 110 men: test-retest correlations from duplicate questionnaires and correlations of clinical measurements of height, weight, and circumference measurements with their self-reported values. Self-reported height and weight showed strong agreement with the duplicate questionnaires (r=0.98 and r=0.97, respectively) and with the clinic measurements of these variables (r=0.96 for both). There were reasonable but somewhat weaker test-retest correlations for self-reported waist circumference (r=0.84), hip circumference (r=0.79), and chest circumference (r=0.93). Self-reported body circumferences also correlated reasonably with the clinic circumference measurements of the waist (r=0.68), hips (r=0.63), and chest (r=0.77).

We estimated that 15% to 19% of the subjects who received our questionnaire responded (uncertainty due to an unknown number of race participants who received the questionnaire and undeliverable addresses). Physician-supplied HDL concentrations were obtained for 26% of the respondents. The remainder either did not give permission to release medical data (27%), had no HDL cholesterol measurements in their medical record (22%), or their physicians did not respond (25%).

Multiple regression analyses were used to test for linear relationships between distances run and risk factor levels and to assess the significance of these relationships when adjusted for other variables. Linear trends for proportions were tested using the estimated trends and SEs for a linear contrast among categorical variables.27 Logistic regression analysis was used for modeling discrete dependent variables.

The best 10-km race times during the past 5 years were obtained for 5915 (83.8%) of the 7059 male runners and 1449 (78.9%) of the 1837 female runners. Compared with those lacking these data, men and women who provided their best race times ran significantly (P<.05) further each week (mean difference[±SE], 11.7±0.6 and 11.6±1.0 km for men and women, respectively) and correspondingly had significantly higher HDL cholesterol concentrations (mean difference[±SE], 0.07±0.01 mmol/L [2.6±0.4 mg/dL] and 0.06±0.02 mmol/L [2.2±0.9 mg/dL], respectively) and lower pulse rates (mean difference[±SE], −2.4±0.4 and −3.1±0.8/min, respectively), diastolic blood pressures (mean difference[±SE], −0.6±0.3 and −1.3±0.6 mm Hg, respectively), BMIs (mean difference[±SE], −0.7±0.1 and −0.6±0.2 kg/m2, respectively), and plasma triglyceride concentrations (mean difference[±SE], −0.10±0.03 mmol/L [−9.0±2.9 mg/dL] and −0.16±0.06 mmol/L [−14.0±5.1 mg/dL], respectively). There were no significant differences in education level; menstrual status; hormone use; or intake of alcohol, red meat, fish, fruit, aspirin, or vitamins between those having and those lacking these data. Men reporting race times were a mean (±SE) of 1.4±0.3 years younger than those who did not (P<.001), but among women age was not related to the presence of these data (P=.25). The best 10-km race times were converted to kilometers per hour in all analyses. The characteristics of the male and female runners who provided 10-km race times are displayed in Table 1.

Table Graphic Jump LocationTable 1. Characteristics of Male and Female Runners Who Provided Their Best 10-km Performance Times*
AGE AND RUNNING DISTANCE

In both men and women, age and weekly running distance accounted for 40% of the variance in best running velocity during a 10-km race. The effects on velocity are illustrated in Figure 1 and Figure 2. The age-related decline in running velocity was significant at all training distances and became more pronounced (P<.01) at higher weekly distances. In men, the annual decline in velocity averaged (regression coefficient [±SE]) −0.055±0.005 km/h for distances of less than 24 km/wk; −0.067±0.003 km/h for distances between 24 and 48 km/wk; −0.075±0.004 km/h for distances between 48 and 72 km/wk; and −0.099±0.008 km/h for distances exceeding 72 km/wk (for all, P<.001). The corresponding declines in women were −0.05±0.01; −0.06±0.01; −0.08±0.01; and −0.11±0.02 km/h per year, respectively (for all, P<.001). The figures also show that running velocity increased with weekly running distance regardless of age. Per kilometer run per week, running velocity increased (regression coefficient[±SE]) 0.049±0.002 km/h for men younger than 40 years (P<.001); 0.049±0.001 km/h for men between 40 and 50 years (P<.001); 0.042±0.002 km/h for men between 50 and 60 years (P<.001); and 0.039±0.003 km/h for men 60 years and older (for all, P<.001). The corresponding increases for women were 0.05±0.01 (P<.001), 0.06±0.00 (P<.001), 0.04±0.01 (P<.001), and 0.01±0.01 km/h per kilometer run per week (P=.22).

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Figure 1.

Average race speed during best 10-km and marathon races for the preceding 5 years in men. Race times were reported for 10-km races by 5915 men and for marathons by 4014 men.

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Figure 2.

Average race speed during best 10-km and marathon races during a 5-year period in women. Race times were reported for 10-km races by 1449 women and for marathons by 613 women.

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BODY MASS INDEX

Body mass index accounted for an additional 6% of the variance in running velocity in men and 4% in women. Table 2 shows that lower BMIs (the dependent variable) were associated with significantly faster running velocities in both men and women, independent of age and weekly running distance. The relationship between running velocity and BMI may be due to low body weight facilitating faster running velocity, as opposed to faster velocity promoting weight loss. Specifically, change in BMI since the onset of running was related principally to average kilometers run per week (regression coefficient[±SE] −0.032±0.002 kg/m2 reduction in BMI per kilometer, P<.001 for men; −0.019±0.003 kg/m2 reduction in BMI per kilometer, P<.001 for women) but not to race velocity (P=.10 and P=.46 for males and females, respectively) during the best 10-km race when adjusted for age, years spent running, years of education, menstrual status, hormone use, and dietary variables.

Table Graphic Jump LocationTable 2. Regression Slopes (±SE) of Body Mass Index vs Running Velocity (kg/m2 per km/h) in Male and Female Runners Stratified by Age and Weekly Running Distance
INDEPENDENT ASSOCIATION OF 10-km RUNNING VELOCITY WITH CHD RISK FACTORS

Table 3 and Table 4 present the regression coefficients for the independent effects of running velocity and weekly running distance as predictors of CHD risk factors (ie, since both variables are included simultaneously in the regression model, the coefficient for running velocity is adjusted for weekly distance). The analyses suggest that running at faster speeds, independent of weekly running distance, was associated with significantly smaller circumferences of the waist, hips, and chest, significantly lower systolic and diastolic blood pressure, and significantly lower plasma concentrations of triglycerides and ratios of total cholesterol to HDL cholesterol in both men and women. Faster running speeds were also associated with significantly higher HDL cholesterol and significantly lower LDL cholesterol concentrations in men when adjusted for weekly running distance.

Table Graphic Jump LocationTable 3. Multiple Regression Analysis of Risk Factors vs Independent Contributions of Running Velocity and Weekly Running Distance in Male Runners*
Table Graphic Jump LocationTable 4. Multiple Regression Analysis of Risk Factors vs Independent Contributions of Running Velocity and Weekly Running Distance in Female Runners*

Adjustment for BMI eliminates the significance of the effects of running velocity on the ratio of total-HDL cholesterol in both men and women, plasma HDL and LDL cholesterol concentrations in men, and waist and chest circumferences, diastolic blood pressure, and plasma triglyceride concentrations in women. The relationships of running velocity with men's body circumferences, blood pressures, and triglyceride concentrations remain significant when adjusted, as does the relationship between velocity and women's systolic blood pressure.

INDEPENDENT ASSOCIATIONS OF WEEKLY RUNNING DISTANCE ON CHD RISK FACTORS

Men and women who ran longer weekly distances also had significantly higher plasma HDL cholesterol concentrations and narrower waists and hips, regardless of how fast they ran during their best 10-km race. In addition, running distance was associated with lower plasma concentrations of triglycerides and the ratio of total to HDL cholesterol in men, and narrower chest circumferences in women when adjusted for 10-km velocity. Adjustment for BMI produced only modest reductions in the coefficient relating running distance to CHD risk factors.

RELATIVE CALCULATED INFLUENCES OF 10-km RUNNING VELOCITY AND WEEKLY DISTANCE

Standardized regression coefficients provide one method for comparing the relative influences of variables measured on different scales, eg, running velocity measured in kilometers per hour and running amount measured in kilometers per week. The standardized coefficient is the predicted change in the dependent variable (ie, CHD risk factor) corresponding to a difference of 1 SD of the independent variable. Table 3 and Table 4 present the standardized coefficients to compare the relative apparent effects of running distance and running velocity on CHD risk factors. For example, men's waist circumference is calculated to decrease by 0.4 cm per 1 SD increase in running velocity when running amount is held constant, and to decrease by 0.05 cm per 1 SD increase in weekly distance when velocity is constant. Table 3 and Table 4 also present the ratio (in absolute value) of the standardized coefficients. When the ratio is greater than 1, then velocity has a greater calculated effect than running distance; ratios less than 1 show the opposite. All coefficients are adjusted for age; years of education; hormone use; menstrual status; and intakes of alcohol, red meat, fish, fruit, and alcohol. Adjustment for BMI was included as indicated.

For both sexes, running velocity had greater calculated effects on hip circumference, systolic blood pressure, and diastolic blood pressure than weekly running distance. In addition, running velocity was more strongly associated with waist and chest circumferences and plasma concentrations of LDL cholesterol and triglycerides than running distance in men. In contrast, plasma HDL cholesterol levels were more strongly related to running distance than running velocity. When adjusted for BMI, running distance appears to have more than 6 times the calculated effect on concentrations of HDL cholesterol as running velocity in both men and women. Adjustment for BMI diminishes, but does not eliminate, the stronger calculated effect of velocity on blood pressure in both sexes, and waist and chest circumferences in men, compared with the effect of weekly running distance.

Figure 3 displays the relative risk of hypertension in men by age-specific quintiles of weekly running distance and 10-km race velocity. Relative to the lowest quintile, the relative risk reduction is greater when the men were partitioned by running velocity than by weekly running distance. Multiple logistic regression analyses (not displayed) with hypertension as the dependent variable and age, BMI, 10-km race velocity, and weekly running distance as the independent variables showed 10-km race velocity to be significant (P<.001) and weekly running distance as nonsignificant (P=.48) when adjusted for the other variables in the model.

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Figure 3.

Relative risk of hypertension in men by age-specific quintiles of weekly running distance and 10-km race velocity. Hypertension was defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher, or use of medication for blood pressure control (untreated hypertension may be overestimated because it is based on readings from a single clinic visit). One asterisk indicates P=.17; 2 asterisks, P=.65; 3 asterisks, P=.003; 4 asterisks, P=.03; and 5 asterisks, P<.001.

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MARATHON PARTICIPATION

Forty-nine percent of the 5915 men and 40% of the 1449 women participated in at least 1 marathon during the previous 5 years. Male marathon runners had higher concentrations of HDL cholesterol (mean difference[±SE], 0.024±0.009 mmol/L [0.92±0.36 mg/dL] higher; P<.01) and female marathon runners had lower ratios of total cholesterol to HDL cholesterol (−0.10±0.04; P<.03) than nonmarathon runners when adjusted for 10-km race velocity, running distance, years of education, age, hormone use, and diet. Both male and female marathon runners had heavier BMIs than nonmarathon runners (adjusted difference[±SE], 0.14±0.06 kg/m2 [P=.03] for men and 0.32±0.13 kg/m2 [P=.01] for women). Adjustment for BMI did not eliminate the significantly higher levels of HDL cholesterol (adjusted difference[±SE], 0.026±0.009 mmol/L [1.01±0.36 mg/dL]; P=.005) and the significantly lower ratio of total-to-HDL cholesterol (−0.13±0.05; P<.006) of the male and female marathon runners, respectively.

MARATHON RACE VELOCITY

Velocities at marathons, although slower than at 10-km races, exhibited the same relationships to age and weekly training distance (Figure 1 and Figure 2). In men, but not in women, the addition of marathon race velocity to the models of Table 3 and Table 4 was significant for BMI (regression coefficient[±SE], −0.21±0.04 kg/m2 calculated reduction per kilometers per hour; P<.001); waist and chest circumferences (regression coefficient[±SE], −0.67±0.09 and −0.72±0.13 cm calculated reductions per kilometer per hour, respectively; P<.001); concentrations of HDL cholesterol (regression coefficient[±SE], 0.025±0.006 mmol/L [0.95±0.22 mg/dL] calculated increase per kilometer per hour; P<.001); and ratio of total-HDL cholesterol (regression coefficient[±SE], −0.06±0.02 calculated reduction per kilometer per hour; P<.004). Men's and women's hip circumferences, blood pressures, and levels of LDL cholesterol and triglycerides were unrelated to best marathon velocity during the previous 5 years when adjusted for the aforementioned covariates. Adjustment for BMI did not eliminate the significant relationship between the men's marathon race velocities and their waist circumferences (regression coefficient[±SE], −0.33±0.07 cm reduction per kilometer per hour; P<.001); levels of HDL cholesterol (regression coefficient [±SE], 0.021±0.006 mmol/L [0.82±0.22 mg/dL] increase per kilometer per hour; P<.001); and ratio of total-HDL cholesterol (regression coefficient[±SE], −0.04±0.02 reduction per kilometer per hour; P=.04).

COMMENT

The relationship of running performance with maximum oxygen uptake and blood lactate threshold has been demonstrated in both sexes9,28 and in trained11 and untrained individuals.28 Ten-kilometer race performance times are correlated strongly with maximum oxygen uptake9,2931 and blood lactate threshold.9,10,29,30,32 Marathon performance time is also related to maximum oxygen uptake.22,33,34 During a marathon, faster runners work at an intensity requiring 75% of their maximum oxygen uptake, whereas the intensity of slower runners is at only 60%.34 Other less significant factors affecting performance include oxygen consumption at submaximal speeds (ie, running economy), muscle fiber composition, and anaerobic capacity.9,31,33,3537

Figure 1 and Figure 2 show that those who ran for longer distances had greater age-related declines in running velocity than those who ran shorter distances in both sexes. The decline in running speed with age is probably caused by decreases in maximum oxygen uptake9 concomitant to decreases in maximum heart rate and stroke volume.9,10,38,39 Highly trained younger and older runners use approximately the same percentage of their maximum oxygen uptake during 10-km races.10 The running velocity at which blood lactate begins to accumulate declines with age but purportedly remains at approximately the same percentage of maximum oxygen uptake as in comparably trained younger runners.10 A portion of the decline in maximum oxygen uptake with age may be due to loss of muscle mass.40

Table 2, Table 3 and Table 4 show that when adjusted for weekly distance and age, the velocity of male and female runners correlates significantly with lower BMI and circumferences of the waist, hips, and chest. Others have noted that faster 10-km velocities are associated with lower BMI,20 sum of skinfold thicknesses,22 and leaner body composition.41 Champion athletes have lower body weights and less fat than even well-trained athletes of similar age.42 Marti and Howald43 report that running pace predicted changes in truncal fat for a 15-year period in former elite male athletes. In our study, race performance (velocity) was, however, unrelated to weight loss since onset of running, suggesting that lower BMI is a cause rather than the consequence of faster race times. This interpretation is consistent with reports that body weight does not change when training intensity is increased, provided that weekly mileage remains the same,29 and total energy expended during running is primarily related to distance rather than speed.44

Faster runners had lower blood pressure even when adjusted for BMI (Table 3 and Table 4). Data pooled from 22 controlled training studies show an inverse association between changes in diastolic blood pressure and changes in exercise capacity.45 Blair et al46 report a threshold for the hypotensive effects of fitness, the effect being limited to higher fitness levels. Our cross-sectional data do not prove that increasing exercise intensity will reduce blood pressure. For example, inherited variations in maximum oxygen uptake could contribute in part to the ability to run quickly.47

In contrast to blood pressure, plasma HDL cholesterol concentrations were more strongly related to weekly running distance than to 10-km race performance, regardless of adjustment for BMI (Table 3 and Table 4). Population data show that levels of HDL cholesterol are consistently associated with self-reported strenuous exercise habits but not treadmill exercise test performance.48 The physiological processes that enhance treadmill test performance and maximum oxygen uptake appear to be largely independent of the processes that elevate levels of HDL cholesterol in runners for 2 reasons. First, training studies report only weak associations between changes in concentrations of HDL cholesterol and treadmill performance4959 and second, the increases in levels of HDL cholesterol and treadmill performance during training are not concurrent processes, ie, increases in maximum oxygen uptake and treadmill duration occur sooner and at lower exercise levels than those required to increase concentrations of HDL cholesterol.3

We found that runners who had run marathons had higher HDL cholesterol concentrations than those who had not. The ability to finish a marathon requires prolonged running that may have its own physiological effects, including increased use of blood-borne substrates for muscle metabolism relative to that of intramuscular substrates,60 increased use of lipids for muscle metabolism compared with carbohydrates,60 and acute increases in muscle lipoprotein lipase61,62 and the fractional removal rate of plasma triglycerides.63 Increases in muscle lipoprotein lipase may be stimulated by the depletion of intramuscular stores following prolonged running.64 High lipoprotein lipase activity may accelerate very low-density lipoprotein and chylomicron catabolism,65 which may cause HDL levels to increase because of the more rapid transfer of free cholesterol and phospholipids to HDL.65 It may also limit the availability of triglyceride-rich lipoprotein particles for cholesterol-ester triglyceride exchange with HDL, causing HDL cholesteryl ester to accumulate in plasma.66

CAVEATS AND LIMITATIONS

Although these cross-sectional associations do not prove that running faster and greater distances causes these improvements in CHD risk factors, other well-designed, randomized, controlled intervention studies prove causality between running and changes in CHD risk factors.6770 Self-selection may also contribute partially to the association between running level and HDL cholesterol. That men with higher levels of HDL cholesterol will tend to run more when undertaking an exercise program has been demonstrated in 2 studies.71,72 higher HDL cholesterol levels at baseline may be a marker for men genetically endowed with muscle fiber types that make running easier, thereby facilitating weight loss.73

Compared with runners identified from a random geographically defined sample, our sample tended to be leaner (−0.8 kg/m2) and have higher concentrations of HDL cholesterol (0.10 mmol/L [3.86 mg/dL] higher, data not shown), presumably because they tended to be more avid runners and somewhat healthier. An unbiased estimate of the dose-response relationship between CHD risk factors and running distance does not require that the runners be selected at random with respect to running mileage. However, volunteers are expected to differ from nonvolunteers and therefore caution is warranted in extrapolating our estimates to all runners. Only 56000 of the approximately 290000 subjects who were mailed questionnaires responded, and of these 9898 are used in the analysis.

CONCLUSIONS

Our data suggest that the benefits of physical activity depend on both intensity and amount. Reductions in CHD risk associated with being more physically fit and more active may be mediated through different risk factors. Whereas blood pressure was more strongly related to race performance than running amount, the opposite was true for HDL cholesterol. The variables that correlate strongly with race performance in our cross-sectional surveys (eg, diastolic blood pressure [Table 3 and Table 4]) tend to be those that change in association with maximum oxygen uptake in longitudinal trials.45 Conversely, the variable that correlated most weakly with performance cross-sectionally (HDL cholesterol [Table 3 and Table 4]) tends to be unrelated to changes in maximum oxygen uptake when studied longitudinally.4959 Both lower blood pressure and higher levels of HDL cholesterol are expected to contribute independently to lower CHD risks.74 Follow-up studies of this cohort will test whether intensity and duration of exercise both contribute independently to reduced risk of CHD, and whether the additional benefits of running faster outweigh the risks of injury.

Accepted for publication June 19, 1997.

Supported in part by grants HL-45652 and HL-55640 from the National Heart, Lung and Blood Institute, Bethesda, Md. This study was conducted at the Lawrence Berkeley Laboratory, Berkeley, Calif (Department of Energy DE-AC03-76SF00098 to the University of California).

Reprints: Paul T. Williams, PhD, Life Sciences Division, Lawrence Berkeley Laboratory, Bldg 934, Berkeley, CA 94720 (e-mail: PTWilliams@LBL.gov).

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Williams  PT Interactive effects of exercise, alcohol, and vegetarian diet on coronary artery disease risk factors in 9242 runners: The National Runners' Health Study. Am J Clin Nutr. 1997;661197- 1206
Folsom  ARCasperson  CJTaylor  HJ  et al.  Leisure time physical activity and its relationship to coronary risk factors in a population based sample. Am J Epidemiol. 1984;121570- 580
Yasim  S Measuring habitual leisure-time physical activity by recall record questionnaire. Karvonen  MJBarry  AJeds.Physical Activity and the Heart. Springfield, Ill Charles C Thomas Publisher1967;372- 373
Ainsworth  BEJacobs  DR  JrLeon  AS Validity and reliability of self-reported physical activity status: the Lipid Research Clinics questionnaire. Med Sci Sports Exerc. 1993;2592- 98
Mood  AMGraybill  FABoes  DC Introduction to the Theory of Statistics. 3rd ed. New York, NY McGraw-Hill Book Co1974;178- 181
Yoshida  TChida  MIchioka  MSuda  Y Blood lactate parameters related to aerobic capacity and endurance performance. Eur J Appl Physiol. 1987;567- 11
Acevedo  EOGoldfarb  AH Increased training intensity effects on plasma lactate, ventilatory threshold, and endurance. Med Sci Sports Exerc. 1989;21563- 568
Tanaka  KWatanabe  HKonishi  Y  et al.  Longitudinal associations between anaerobic threshold and distance running performance. Eur J Appl Physiol. 1986;55248- 252
Glenmark  BHedberg  GJansson  E Running capacity from adolescence to adulthood: relationship to physical characteristics. Int J Sports Med. 1993;14118- 123
Maffulli  NCapasso  GLancia  A Anaerobic threshold and performance in middle and long distance running. J Sports Med Phys Fitness. 1991;31332- 338
Scrimgeour  AGNoakes  TDAdams  BMyburgh  K The influence of weekly training distance on fractional utilization of maximum aerobic capacity in marathon and ultramarathon runners. Eur J Appl Physiol. 1986;55202- 209
Maughan  RJLeiper  JB Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners. Eur J Appl Physiol. 1983;5280- 87
Baumann  HJaggi  MSoland  FHowald  HSchaub  MC Exercise training induces transitions of myosin isoform subunits within histochemically typed human muscle fibres. Pflugers Arch. 1987;409349- 360
Glenmark  B Skeletal muscle fibre types, physical performance, physical activity and attitude to physical activity in women and men: a follow-up from age 16 to 27. Acta Physiol Scand Suppl. 1994;6231- 47
Ivy  JLWithers  RTVan Handel  PJElger  DHCostill  DL Muscle respiratory capacity and fiber type as determinants of the lactate threshold. J Appl Physiol. 1980;48523- 527
Hagberg  JMAllen  WKSeals  DRHurley  BFEhsani  AAHolloszy  JO A hemodynamic comparison of young and older endurance athletes during exercise. J Appl Physiol. 1986;582041- 2046
Fuchi  TIwaoka  KHiguchi  MKobayashi  S Cardiovascular changes associated with decreased aerobic capacity and aging in long-distance runners. Eur J Appl Physiol. 1989;58884- 889
Fleg  JLLakatta  EG Role of muscle loss in the age-associated reduction in VO2max. J Appl Physiol. 1988;651147- 1151
Tanaka  KMimura  KKim  HS  et al.  Prerequisites in distance running performance of female runners. Ann Physiol Anthropol. 1989;879- 87
Pollock  MLGettman  LRJackson  A  et al.  Body composition of elite class distance runners. N Y Acad Sci. 1977;301361- 370
Marti  BHowald  H Long-term effects of physical training on aerobic capacity: controlled study of former elite athletes. J Appl Physiol. 1990;691451- 1459
Margaria  RCerretelli  PAghemo  PSassi  G Energy cost of running. J Appl Physiol. 1963;18367- 370
Fagard  RHTipton  CM Physical activity, fitness and hypertension. Bouchard  CShephard  RJStephens  Teds.Physical Activity, Fitness and Health. Champaign, Ill Human Kinetics Publishers1994;633- 655
Blair  SNGoodyear  NNGibbons  LWCooper  KH Physical fitness and incidence of hypertension in healthy normotensive men and women. JAMA. 1984;252487- 490
Bouchard  CLesage  RLortie  G Aerobic performance in brothers, dizygotic and monozygotic twins. Med Sci Sports Exerc. 1980;12357- 360
Haskell  WLTaylor  HLWood  PDSchrott  HHeiss  G Strenuous physical activity, treadmill exercise test performance and plasma high-density lipoprotein cholesterol: The Lipid Research Clinics Program Prevalence Study. Circulation. 1980;62 ((4 pt 2)) IV53- IV61
Sutherland  WHWoodhouse  SP Physical activity and plasma lipoprotein lipid concentrations in men. Atherosclerosis. 1980;37285- 292
LaRosa  JCCleary  PMuesing  RAGorman  PHellerstein  HKNaughton  J Effect of long-term moderate physical exercise on plasma lipoproteins: The National Exercise and Heart Disease Project. Arch Intern Med. 1982;1422269- 2274
Peltonen  PMarniemi  JHietanen  EVuori  IEhnholm  C Changes in serum lipids, lipoproteins, and heparin releasable lipolytic enzymes during moderate physical training in man: a longitudinal study. Metabolism. 1981;30518- 526
Brownell  KDBachorik  PSAyerle  RS Changes in plasma lipid and lipoprotein levels in men and women after a program of moderate exercise. Circulation. 1982;65477- 484
Farrell  PABarboriak  J The time course of alterations in plasma lipid and lipoprotein concentrations during eight weeks of endurance training. Atherosclerosis. 1980;37231- 238
Ballantyne  DClark  RSBallantyne  FC The effect of physical training on plasma lipids and lipoproteins. Clin Cardiol. 1981;41- 4
Huttunen  JKLansimies  EVoutilainen  E  et al.  Effect of moderate physical exercise on serum lipoproteins: a controlled clinical trial with special reference to serum high-density lipoproteins. Circulation. 1979;601220- 1229
Ballantyne  FCClark  RSSimpson  HSBallantyne  D The effect of moderate physical exercise on the plasma lipoprotein subfractions of male survivors of myocardial infarction. Circulation. 1982;65913- 918
Despres  JPBouchard  CSavard  RTremblay  AAllard  C Lack of relationship between changes in adiposity and plasma lipids following endurance training. Atherosclerosis. 1985;54135- 143
Farrell  PAMaksud  MGPollock  ML  et al.  A comparison of plasma cholesterol, triglycerides, and high density lipoprotein-cholesterol in speed skaters, weightlifters and non-athletes. Eur J Appl Physiol. 1982;4877- 82
Raz  IRosenblit  HKark  JP Effect of moderate exercise on serum lipids in young men with low high density lipoprotein-cholesterol. Arteriosclerosis. 1988;8245- 251
Essen  BHagenfeldt  LKaijser  L Utilization of blood-borne and intramuscular substrates during continuous and intermittent exercise in man. J Physiol. 1977;265489- 506
Lithell  HOrlander  JSchele  RSjodin  BKarlsson  J Changes in lipoprotein-lipase activity and lipid stores in human skeletal muscle with prolonged heavy exercise. Acta Physiol Scand. 1979;107257- 261
Lithell  HSchele  RVessby  BJacobs  I Lipoproteins, lipoprotein lipase, and glycogen after prolonged physical activity. J Appl Physiol. 1984;57698- 702
Annuzzi  GJansson  EKaijser  LHolmquist  LCarlson  LA Increased removal rate of exogenous triglycerides after prolonged exercise in man: time course and effect of exercise duration. Metabolism. 1987;36438- 443
Jacobs  ILithell  HKarlsson  J Dietary effects on glycogen and lipoprotein lipase activity in skeletal muscle in man. Acta Physiol Scand. 1982;11585- 90
Nikkilä  EA HDL in relation to the metabolism of triglyceride-rich lipoproteins. Miller  NEMiller  GJeds.Clinical and Metabolic Aspects of High-Density Lipoproteins. Amsterdam, the Netherlands Elsevier Science Publishers1984;217- 245
Tall  AR Plasma lipid transfer proteins. J Lipid Res. 1986;27361- 367
Wood  PDWilliams  PTHaskell  WL Physical activity and high density lipoproteins. Miller  NEMiller  GJeds.Clinical and Metabolic Aspects of High-Density Lipoproteins. Amsterdam, the Netherlands Elsevier Science Publishers1984;133- 165
Krummel  DEtherton  TDPeterson  SKris-Etherton  PM Effects of exercise on plasma lipids and lipoproteins of women. Proc Soc Exp Biol Med. 1993;204123- 137
Wood  PDStefanick  MLDreon  D  et al.  Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise. N Engl J Med. 1988;3191173- 1179
Wood  PDStefanick  MLWilliams  PTHaskell  WL The effects on plasma lipoproteins of a prudent weight-reducing diet, with or without exercise, in overweight men and women. N Engl J Med. 1991;325461- 466
Williams  PTWood  PDHaskell  WLVranizan  KM The effects of running mileage and duration on plasma lipoprotein levels. JAMA. 1982;24726174- 26179
Williams  PTKrauss  RMStefanick  MLVranizan  KMWood  PDS Effects of weight loss by exercise or by dieting on plasma high density lipoprotein levels in men with low, intermediate and normal-to-high HDL at baseline. Metabolism. 1994;43917- 924
Williams  PT Muscle fiber composition and lipoproteins. Atherosclerosis. 1993;98251- 252
Anderson  KMWilson  PWFOdell  PMKannel  WB An updated coronary risk profile: a statement for health professionals. Circulation. 1991;75357- 364

Figures

Place holder to copy figure label and caption
Figure 1.

Average race speed during best 10-km and marathon races for the preceding 5 years in men. Race times were reported for 10-km races by 5915 men and for marathons by 4014 men.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 2.

Average race speed during best 10-km and marathon races during a 5-year period in women. Race times were reported for 10-km races by 1449 women and for marathons by 613 women.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 3.

Relative risk of hypertension in men by age-specific quintiles of weekly running distance and 10-km race velocity. Hypertension was defined as systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher, or use of medication for blood pressure control (untreated hypertension may be overestimated because it is based on readings from a single clinic visit). One asterisk indicates P=.17; 2 asterisks, P=.65; 3 asterisks, P=.003; 4 asterisks, P=.03; and 5 asterisks, P<.001.

Graphic Jump Location

Tables

Table Graphic Jump LocationTable 1. Characteristics of Male and Female Runners Who Provided Their Best 10-km Performance Times*
Table Graphic Jump LocationTable 2. Regression Slopes (±SE) of Body Mass Index vs Running Velocity (kg/m2 per km/h) in Male and Female Runners Stratified by Age and Weekly Running Distance
Table Graphic Jump LocationTable 3. Multiple Regression Analysis of Risk Factors vs Independent Contributions of Running Velocity and Weekly Running Distance in Male Runners*
Table Graphic Jump LocationTable 4. Multiple Regression Analysis of Risk Factors vs Independent Contributions of Running Velocity and Weekly Running Distance in Female Runners*

References

Williams  PT Relationship of distance run per week to coronary heart disease risk factors in 8,283 male runners: The National Runners' Health Study. Arch Intern Med. 1997;157191- 198
Williams  PT High density lipoprotein cholesterol and other risk factors for coronary heart disease in female runners. N Engl J Med. 1996;3341298- 1303
Williams  PTWood  PDHaskell  WLVranizan  K The effects of running mileage and duration on plasma lipoprotein levels. JAMA. 1982;2472674- 2679
Wood  PDStefanick  MLDreon  DM  et al.  Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise. N Engl J Med. 1988;3191173- 1179
Wood  PDStefanick  MLWilliams  PTHaskell  WL The effects on plasma lipoproteins of a prudent weight-reducing diet, with or without exercise, in overweight men and women. N Engl J Med. 1991;325461- 466
Pate  RRPratt  MBlair  SN  et al.  Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA. 1995;273402- 407
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Joyner  MJ Physiological limiting factors and distance running: influence of gender and age on record performances. Exerc Sport Sci Rev. 1993;21103- 133
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Allen  WKSeals  DRHurley  BFErhsani  AAHagberg  JM Lactate threshold and distance running performance in young and older endurance athletes. J Appl Physiol. 1985;581281- 1284
Farrell  PAWilmore  JHCoyle  EFBilling  JECostill  DL Plasma lactate accumulation and distance running performance. Med Sci Sports. 1979;11338- 344
Cooper  KH A means of assessing maximum oxygen uptake-correlation between field and treadmill testing. JAMA. 1968;203201- 204
Rotkis  TCCote  RCoyle  EWilmore  JH Relationship between high density lipoprotein cholesterol and weekly running mileage. J Cardiac Rehabil. 1982;2109- 112
Sady  SPThompson  PDCullinane  EMKantor  MADomagala  EHerber  PN Prolonged exercise augments plasma triglyceride clearance. JAMA. 1986;2562552- 2555
Nakamura  NUzawa  HMaeda  HInomoto  T Physical fitness: its contribution to serum high density lipoprotein. Atherosclerosis. 1983;48173- 183
Kavanagh  TShephard  RJLindley  LJPieper  M Influence of exercise and life-style variables upon high density lipoprotein cholesterol after myocardial infarction. Arteriosclerosis. 1983;3249- 259
Young  DRSteinhardt  MA The importance of physical fitness versus physical activity for coronary artery disease risk factors: a cross-sectional analysis. Res Q Exerc Sport. 1993;64377- 384
Smith  MLMitchell  JH Cardiorespiratory adaptations to exercise training. Durstene  JLKing  ACPainter  PLRoitman  JLZwiren  LDeds.ACSM'S Resource Manual for Guidelines for Exercise Testing and Prescription. 2nd ed. Philadelphia, Pa Lea & Febiger1993;75- 81
Lash  JMSherman  WM Skeletal muscle function and adaptations to training. Durstene  JLKing  ACPainter  PLRoitman  JLZwiren  LDeds.ACSM'S Resource Manual for Guidelines for Exercise Testing and Prescription. 2nd ed. Philadelphia, Pa Lea & Febiger1993;93- 105
Hagan  RDSmith  MGGettman  LR Marathon performance in relation to maximal aerobic power and training indices. Med Sci Sports Exerc. 1981;13185- 189
Hagan  RDUpton  SJDuncan  JJGettman  LR Marathon performance in relation to maximal aerobic power and training indices in female distance runners. Br J Sports Med. 1987;213- 7
Bale  PBradbury  DColley  E Anthropometric and training variables related to 10-km running performance. Br J Sports Med. 1986;20170- 173
Williams  PT Interactive effects of exercise, alcohol, and vegetarian diet on coronary artery disease risk factors in 9242 runners: The National Runners' Health Study. Am J Clin Nutr. 1997;661197- 1206
Folsom  ARCasperson  CJTaylor  HJ  et al.  Leisure time physical activity and its relationship to coronary risk factors in a population based sample. Am J Epidemiol. 1984;121570- 580
Yasim  S Measuring habitual leisure-time physical activity by recall record questionnaire. Karvonen  MJBarry  AJeds.Physical Activity and the Heart. Springfield, Ill Charles C Thomas Publisher1967;372- 373
Ainsworth  BEJacobs  DR  JrLeon  AS Validity and reliability of self-reported physical activity status: the Lipid Research Clinics questionnaire. Med Sci Sports Exerc. 1993;2592- 98
Mood  AMGraybill  FABoes  DC Introduction to the Theory of Statistics. 3rd ed. New York, NY McGraw-Hill Book Co1974;178- 181
Yoshida  TChida  MIchioka  MSuda  Y Blood lactate parameters related to aerobic capacity and endurance performance. Eur J Appl Physiol. 1987;567- 11
Acevedo  EOGoldfarb  AH Increased training intensity effects on plasma lactate, ventilatory threshold, and endurance. Med Sci Sports Exerc. 1989;21563- 568
Tanaka  KWatanabe  HKonishi  Y  et al.  Longitudinal associations between anaerobic threshold and distance running performance. Eur J Appl Physiol. 1986;55248- 252
Glenmark  BHedberg  GJansson  E Running capacity from adolescence to adulthood: relationship to physical characteristics. Int J Sports Med. 1993;14118- 123
Maffulli  NCapasso  GLancia  A Anaerobic threshold and performance in middle and long distance running. J Sports Med Phys Fitness. 1991;31332- 338
Scrimgeour  AGNoakes  TDAdams  BMyburgh  K The influence of weekly training distance on fractional utilization of maximum aerobic capacity in marathon and ultramarathon runners. Eur J Appl Physiol. 1986;55202- 209
Maughan  RJLeiper  JB Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners. Eur J Appl Physiol. 1983;5280- 87
Baumann  HJaggi  MSoland  FHowald  HSchaub  MC Exercise training induces transitions of myosin isoform subunits within histochemically typed human muscle fibres. Pflugers Arch. 1987;409349- 360
Glenmark  B Skeletal muscle fibre types, physical performance, physical activity and attitude to physical activity in women and men: a follow-up from age 16 to 27. Acta Physiol Scand Suppl. 1994;6231- 47
Ivy  JLWithers  RTVan Handel  PJElger  DHCostill  DL Muscle respiratory capacity and fiber type as determinants of the lactate threshold. J Appl Physiol. 1980;48523- 527
Hagberg  JMAllen  WKSeals  DRHurley  BFEhsani  AAHolloszy  JO A hemodynamic comparison of young and older endurance athletes during exercise. J Appl Physiol. 1986;582041- 2046
Fuchi  TIwaoka  KHiguchi  MKobayashi  S Cardiovascular changes associated with decreased aerobic capacity and aging in long-distance runners. Eur J Appl Physiol. 1989;58884- 889
Fleg  JLLakatta  EG Role of muscle loss in the age-associated reduction in VO2max. J Appl Physiol. 1988;651147- 1151
Tanaka  KMimura  KKim  HS  et al.  Prerequisites in distance running performance of female runners. Ann Physiol Anthropol. 1989;879- 87
Pollock  MLGettman  LRJackson  A  et al.  Body composition of elite class distance runners. N Y Acad Sci. 1977;301361- 370
Marti  BHowald  H Long-term effects of physical training on aerobic capacity: controlled study of former elite athletes. J Appl Physiol. 1990;691451- 1459
Margaria  RCerretelli  PAghemo  PSassi  G Energy cost of running. J Appl Physiol. 1963;18367- 370
Fagard  RHTipton  CM Physical activity, fitness and hypertension. Bouchard  CShephard  RJStephens  Teds.Physical Activity, Fitness and Health. Champaign, Ill Human Kinetics Publishers1994;633- 655
Blair  SNGoodyear  NNGibbons  LWCooper  KH Physical fitness and incidence of hypertension in healthy normotensive men and women. JAMA. 1984;252487- 490
Bouchard  CLesage  RLortie  G Aerobic performance in brothers, dizygotic and monozygotic twins. Med Sci Sports Exerc. 1980;12357- 360
Haskell  WLTaylor  HLWood  PDSchrott  HHeiss  G Strenuous physical activity, treadmill exercise test performance and plasma high-density lipoprotein cholesterol: The Lipid Research Clinics Program Prevalence Study. Circulation. 1980;62 ((4 pt 2)) IV53- IV61
Sutherland  WHWoodhouse  SP Physical activity and plasma lipoprotein lipid concentrations in men. Atherosclerosis. 1980;37285- 292
LaRosa  JCCleary  PMuesing  RAGorman  PHellerstein  HKNaughton  J Effect of long-term moderate physical exercise on plasma lipoproteins: The National Exercise and Heart Disease Project. Arch Intern Med. 1982;1422269- 2274
Peltonen  PMarniemi  JHietanen  EVuori  IEhnholm  C Changes in serum lipids, lipoproteins, and heparin releasable lipolytic enzymes during moderate physical training in man: a longitudinal study. Metabolism. 1981;30518- 526
Brownell  KDBachorik  PSAyerle  RS Changes in plasma lipid and lipoprotein levels in men and women after a program of moderate exercise. Circulation. 1982;65477- 484
Farrell  PABarboriak  J The time course of alterations in plasma lipid and lipoprotein concentrations during eight weeks of endurance training. Atherosclerosis. 1980;37231- 238
Ballantyne  DClark  RSBallantyne  FC The effect of physical training on plasma lipids and lipoproteins. Clin Cardiol. 1981;41- 4
Huttunen  JKLansimies  EVoutilainen  E  et al.  Effect of moderate physical exercise on serum lipoproteins: a controlled clinical trial with special reference to serum high-density lipoproteins. Circulation. 1979;601220- 1229
Ballantyne  FCClark  RSSimpson  HSBallantyne  D The effect of moderate physical exercise on the plasma lipoprotein subfractions of male survivors of myocardial infarction. Circulation. 1982;65913- 918
Despres  JPBouchard  CSavard  RTremblay  AAllard  C Lack of relationship between changes in adiposity and plasma lipids following endurance training. Atherosclerosis. 1985;54135- 143
Farrell  PAMaksud  MGPollock  ML  et al.  A comparison of plasma cholesterol, triglycerides, and high density lipoprotein-cholesterol in speed skaters, weightlifters and non-athletes. Eur J Appl Physiol. 1982;4877- 82
Raz  IRosenblit  HKark  JP Effect of moderate exercise on serum lipids in young men with low high density lipoprotein-cholesterol. Arteriosclerosis. 1988;8245- 251
Essen  BHagenfeldt  LKaijser  L Utilization of blood-borne and intramuscular substrates during continuous and intermittent exercise in man. J Physiol. 1977;265489- 506
Lithell  HOrlander  JSchele  RSjodin  BKarlsson  J Changes in lipoprotein-lipase activity and lipid stores in human skeletal muscle with prolonged heavy exercise. Acta Physiol Scand. 1979;107257- 261
Lithell  HSchele  RVessby  BJacobs  I Lipoproteins, lipoprotein lipase, and glycogen after prolonged physical activity. J Appl Physiol. 1984;57698- 702
Annuzzi  GJansson  EKaijser  LHolmquist  LCarlson  LA Increased removal rate of exogenous triglycerides after prolonged exercise in man: time course and effect of exercise duration. Metabolism. 1987;36438- 443
Jacobs  ILithell  HKarlsson  J Dietary effects on glycogen and lipoprotein lipase activity in skeletal muscle in man. Acta Physiol Scand. 1982;11585- 90
Nikkilä  EA HDL in relation to the metabolism of triglyceride-rich lipoproteins. Miller  NEMiller  GJeds.Clinical and Metabolic Aspects of High-Density Lipoproteins. Amsterdam, the Netherlands Elsevier Science Publishers1984;217- 245
Tall  AR Plasma lipid transfer proteins. J Lipid Res. 1986;27361- 367
Wood  PDWilliams  PTHaskell  WL Physical activity and high density lipoproteins. Miller  NEMiller  GJeds.Clinical and Metabolic Aspects of High-Density Lipoproteins. Amsterdam, the Netherlands Elsevier Science Publishers1984;133- 165
Krummel  DEtherton  TDPeterson  SKris-Etherton  PM Effects of exercise on plasma lipids and lipoproteins of women. Proc Soc Exp Biol Med. 1993;204123- 137
Wood  PDStefanick  MLDreon  D  et al.  Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise. N Engl J Med. 1988;3191173- 1179
Wood  PDStefanick  MLWilliams  PTHaskell  WL The effects on plasma lipoproteins of a prudent weight-reducing diet, with or without exercise, in overweight men and women. N Engl J Med. 1991;325461- 466
Williams  PTWood  PDHaskell  WLVranizan  KM The effects of running mileage and duration on plasma lipoprotein levels. JAMA. 1982;24726174- 26179
Williams  PTKrauss  RMStefanick  MLVranizan  KMWood  PDS Effects of weight loss by exercise or by dieting on plasma high density lipoprotein levels in men with low, intermediate and normal-to-high HDL at baseline. Metabolism. 1994;43917- 924
Williams  PT Muscle fiber composition and lipoproteins. Atherosclerosis. 1993;98251- 252
Anderson  KMWilson  PWFOdell  PMKannel  WB An updated coronary risk profile: a statement for health professionals. Circulation. 1991;75357- 364

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