Effects of exercise on lipoprotein(a)

Lipoprotein(a) [Lp(a)] is a unique lipoprotein complex in the blood. At hig h levels (>30 mg/dl), Lp(a) is considered an independent risk factor for ca rdiovascular diseases. Serum Lp(a) levels are largely genetically determine d, remain relatively constant within a given individual, and do not appear to be altered by factors known to influence other lipoproteins (e.g. lipid- lowering drugs, dietary modification and change in body mass). Since regula r exercise is associated with favourable changes in lipoproteins in the blo od, recent attention has focused on whether serum Lp(a) levels are also inf luenced by physical activity. Population and cross-sectional studies consis tently show a lack of association between serum Lp(a) levels and regular mo derate physical activity. Moreover, exercise intervention studies extending from 12 weeks to 4 years indicate that serum Lp(a) levels do not change in response to moderate exercise training, despite improvements in fitness le vel and other lipoprotein levels in the blood. However, recent studies sugg est the possibility that serum Lp(a) levels may increase in response to int ense load-bearing exercise training, such as distance running or weight lif ting, over several months to years. Cross-sectional studies have reported a bnormally high serum Lp(a) levels in experienced distance runners and body builders who train for 2 to 3 hours each day. However, the possible confoun ding influence of racial or ethnic factors in these studies cannot be disco unted. Recent intervention studies also suggest that 9 to 12 months of intense exe rcise training may elevate serum Lp(a) levels. However, these changes are g enerally modest (10 to 15%) and, in most individuals, serum Lp(a) levels re main within the recommended range. It is unclear whether increased serum Lp (a) levels after intense exercise training are of clinical relevance, and w hether certain Lp(a) isoforms are more sensitive to the effects of exercise training. Since elevation of both low density lipoprotein cholesterol (LDL -C) and Lp(a) levels in the blood exerts a synergistic effect on cardiovasc ular disease risk, attention should focus on changing lifestyle factors to decrease LDL-C (e.g. dietary intervention) and increase high density lipopr otein cholesterol (e.g. exercise) levels in the blood.