Exercise and risk factors associated with metabolic syndrome in older adults

Background: Older people with elevated blood pressure (BP) often have metabolic syndrome, a clustering of central obesity, insulin resistance, dyslipidemia, and hypertension. Exercise reduces many of these risk factors. This study examined whether the benefits of exercise on cardiovascular and metabolic disease risk factors are mediated by exercise-induced changes in fitness or body composition. Methods: Randomized controlled trial, comprising 6 months of exercise training, conducted between July 1999 and November 2003. Participants included men and women (n = 115) aged 55 to 75 years with untreated systolic blood pressure (SBP) of 130 to 159 or diastolic blood pressure of (DPB) 85 to 99 mm Hg. Fitness measures included BP, lipids. lipoproteins, insulin, and glucose; peak oxygen uptake and muscle strength; and body composition measured by anthropometry, dual-energy x-ray absorptiometry, and magnetic resonance imaging. Results: A total of 51 men and 53 women completed the trial. Exercise significantly increased aerobic and muscle fitness, lean mass, and high-density lipoprotein cholesterol and reduced total and abdominal fat. DBP was reduced more among exercisers. There were no associations among changes in fitness with risk factors. Reductions in total body and abdominal fat and increases in leanness. largely independent of weight loss, were associated with improved SBP, DBP, total cholesterol, very low-density lipoprotein cholesterol, triglycerides, lipoprotein(a), and insulin sensitivity. At baseline, 42.3% of participants had metabolic syndrome. At 6 months, nine exercisers (17.7%) and eight controls (15.1%) no longer had metabolic syndrome, whereas four controls (7.6%) and no exercisers developed it (p = 0.06). Conclusions: Although exercise improved fitness, the reductions in total and abdominal fatness and increase in leanness were more strongly associated with favorable changes in risk factors for cardiovascular disease and diabetes, including those that constitute metabolic syndrome. (C) 2005 American Journal of Preventive Medicine.