Regular Physical Activity and Risk Factors for Coronary Heart Disease
To the Editor:
We read with interest the article by Hsieh et al1 reporting a dose-dependent benefit from small amounts of physical activity on some coronary risk factors in Japan. According to the Seven Countries Study,2 Japanese people exhibit a very low incidence of coronary heart disease (CHD). Thus Hsieh et al found, in a low-risk population, an effect of regular physical activity on hypertension, abnormal glucose tolerance, hypertriglyceridemia, and low HDL cholesterol levels, but they did not see any effect on total plasma cholesterol. Unfortunately, LDL cholesterol, the most important risk factor for CHD,3 was not investigated in their study.
To elucidate the effects of exercise on lipoprotein metabolism, we performed a prospective study of aerobic exercise in individuals with high risk for CHD, including elevated LDL cholesterol levels. Herein, we report preliminary data on plasma lipoprotein lipids and apolipoproteins. A group of 147 sedentary subjects (age, 50±16 years; 98 male, 49 female; body mass index [BMI], 26±3 kg/m2) was compared with a group of 147 subjects (age, 50±23 years; 110 male, 37 female; BMI, 25±3 kg/m2) who regularly performed aerobic exercise (3 or more training sessions per week). This exercise group encompassed 147 individuals and thus was of similar magnitude as the respective group of Hsieh et al and was well matched with our sedentary group. No diet or lipid-lowering therapy was instituted in any individual in either group. Plasma lipoprotein lipids and apolipoproteins were determined by routine methods. We assessed aerobic fitness during an incremental bicycle ergometer test by recording maximal oxygen uptake (V̇o2max). As expected, a statistically significant higher V̇o2max was found in the subjects who performed regular aerobic exercise than in sedentary people (3.64±0.68 versus 2.13±0.46 L/min; P<0.01).
In accordance with Hsieh et al, we found a significant benefit from regular physical activity on triglycerides (196±155 versus 148±84 mg/dL in sedentary and physically active individuals, respectively; P<0.001) and on HDL cholesterol (52±15 versus 55±14 mg/dL; P<0.05). Also, compared with no physical activity, regularly performed aerobic exercise was significantly associated with lower LDL cholesterol (154±42 versus 129±41 mg/dL; P<0.001), lower apolipoprotein B (133±33 versus 109±30 mg/dL; P<0.001), and higher apolipoprotein A levels (158±37 versus 177±29 mg/dL; P<0.001). Lipoprotein(a) was not affected significantly.
Our findings indicate that regularly performed aerobic exercise improves a broad array of lipid risk factors. In accordance with Hsieh et al, we also found lower triglyceride and higher HDL cholesterol levels. In addition, and probably more importantly, we herein report a marked difference in LDL cholesterol and apolipoprotein B levels between sedentary people and individuals who perform aerobic exercise ≈3 times per week. These data expand the findings of Hsieh et al and emphasize that well-defined and regularly performed aerobic exercise also reduces LDL cholesterol and apolipoprotein B, the key risk factors of CHD.
- Copyright © 1998 by American Heart Association
Hsieh SD, Yoshinaga H, Muto T, Sakurai Y. Regular physical activity and coronary risk factors in Japanese men. Circulation. 1998;97:661–665.
Verschuren WM, Jacobs DR, Bloemberg BP, Kromhout D, Menotti A, Aravanis C, Blackburn H, Buzina R, Dontas AS, Fidanza F. Serum total cholesterol and long-term coronary heart disease mortality in different cultures: twenty- five-year follow-up of the Seven Countries Study. JAMA. 1995;274:131–136.
According to the Helsinki Heart Study report, elevating HDL cholesterol levels may be at least as effective as lowering LDL cholesterol levels in the prevention of coronary heart disease.R1 It has also been reported that HDL cholesterol levels increase significantly after exercise but that total cholesterol and LDL cholesterol levels do not change significantly.R2 R3
LDL cholesterol is not on our routine examination list. However, we calculated LDL cholesterol values according to the formula of Friedewald when triglyceride levels were <400 mg/dL.R4 LDL cholesterol levels were 133.4±32.2, 129.7±31.7, 131.4±30.3, and 128.6±28.0 mg/dL (mean±SD) for the sedentary groups and the groups who exercised 1, 2, and ≥3 days per week, respectively; there was a significant difference among groups (P=0.0377 by 1-way ANOVA). However, we did not find any difference between the groups by the Tukey-Kramer honestly significant difference test. We think the study of Benzer and colleagues differed from ours in the following ways: (1) their studies comprised both men and women; (2) the body mass index of the sedentary group was a little higher than in the exercise group in their studies (mean, 26 versus 25 kg/m2); and (3) the degree of physical activity might have been higher in their studies.
In any case, the effect of the degree of physical activity on total cholesterol and LDL cholesterol levels requires further exploration.
Manninen V, Elo MO, Frick MH, Haapa K, Heinonen OP, Heinsalmi P, Helo P, Huttunen, JK, Kaitaniemi P, Koskinen P, Mäenpää H, Mälkönen M, Mänttäri M, Norola S, Pasternack A, Pikkarainen J, Romo M, Sjöblom T, Nikkilä EA. Lipid alterations and decline in the incidence of coronary heart disease in the Helsinki Heart Study. JAMA. 1988;260:641–651.
Thompson PD, Cullinane EM, Sady SP, Flynn MM, Bernier DN, Kantor MA, Saritelli AL, Herbert PN. Modest changes in high-density lipoprotein concentration and metabolism with prolonged exercise training. Circulation. 1988;78:25–34.
Wood PD, Stefanick ML, Dreon DM, Frey-Hewitt B, Garay SC, Williams PT, Superko HR, Fortmann SP, Albers JJ, Vranizan KM, Ellsworth NM, Terry RB, Haskell WL. Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise. N Engl J Med. 1988;319:1173–1179.
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18:499–502.