Regular Physical Activity and Risk Factors for Coronary Heart Disease
Institute of Sports Medicine
Department of Medicine and Vorarlberg Institute for Vascular Investigation and Treatment, Landeskrankenhaus, Feldkirch, Austria
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 (
O2max). As expected, a
statistically significant higher
O2max 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.
References
1.
Hsieh SD, Yoshinaga H, Muto T, Sakurai Y. Regular
physical activity and coronary risk factors in Japanese men.
Circulation. 1998;97:661–665.
2.
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.
3. Ginsberg HN. Lipoprotein metabolism and its relationship to atherosclerosis. Med Clin North Am. 1994;78:1–20.[Medline] [Order article via Infotrieve]
Response
Medical Center of Health Science, Toranomon Hospital, Tokyo, Japan
Department of Public Health Juntendo University, Tokyo, Japan
Department of Public Health National Defense Medical College, Saitama, Japan
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.1 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.2 3
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.4 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.
References
1.
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.
2.
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.
3. 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.[Abstract]
4. 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.[Abstract]
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