Physical activity, obesity and blood lipids

Abstract

PURPOSE: To present the evidence concerning the in¯uence of physical activity on the dyslipidaemia of obesity and overweight. METHODS: Review of a personal library of literature on the interactions of physical activity, lipoprotein metabolism and body fatness. SUMMARY OF FINDINGS: Obesity, in particular abdominal obesity, is associated with dyslipidaemia Ð speci®cally elevated plasma concentrations of triacylglycerol (TAG) in the fasted state, an exaggerated postprandial rise in plasma TAG, low concentrations of high density lipoprotein cholesterol (HDL) and possibly a preponderance of small dense low density lipoproteins. Regular physical activity contributes to the avoidance of overweight and hence to the development of dyslipidaemia. Although low levels of body fatness contribute to the high levels of HDL cholesterol and the low levels of TAG in trained people there are other important determinants of these characteristics. In particular, exercise (and probably training, that is regular, frequent exercise over months and years) enhances the metabolic capacity for TAG, possibly through mechanisms involving increased activity of lipoprotein lipase. This, in turn, has effects on other lipoprotein species such that the transport of TAG and cholesterol in the circulation is improved. There is evidence for a dose ± response relationship, with for example, higher levels of HDL cholesterol in men and women who expend more energy in exercise. For the majority of healthy, sedentary adults frequent, moderate intensity exercise equivalent to a total gross energy expenditure of about 8.5 MJ per week is probably a suf®cient to in¯uence lipoprotein lipids.

Serum lipids, serum insulin, plasma fibrinogen and aerobic capacity in obese and non-obese Singaporean boys

“…In adults both physical activity and aerobic ®tness are associated with healthy lipid pro®les and these relationships may be mediated, in part, through body fatness. 20 Whether these ®ndings are applicable to children is uncertain. There is evidence that obese children are less active than non-obese children and that they have a lower aerobic capacity.…”

Efeito da dieta e do ciclismo indoor sobre a composição corporal e nível sérico lipídico

“…However, it is suggested that the exacerbated increase in the lipolysis rate results in high concentrations of nonesterified fatty acids, contributing to increased hepatic synthesis of VLDL. Besides, it inhibits glucose uptake stimulated by insulin, in a dose-dependent way, resulting in insulin resistance 28 .…”

Dieta hiperlipídica e capacidade secretória de insulina em ratos

“…A ingestão aumentada de lipídeos pode levar ao aparecimento de obesidade, diabetes tipo 2 e doenças cardiovasculares 6 . Em face do exposto, neste estudo verificamos as alterações provocadas por uma dieta hiperlipídica palatável, administrada a ratos por período prolongado.…”