NEW ORLEANS — Moderate aerobic fitness has a significant beneficial effect on various components of metabolic syndrome in nondiabetic overweight or obese African American women.
In 68 African American women with a mean age of 47 years and a mean body mass index of 33.6 kg/m
The overall prevalence of metabolic syndrome was 25%, with the 29 women with moderate aerobic fitness having the lowest prevalence (14%), compared with the 14 women with low aerobic fitness (29%) and the 25 women with very low aerobic fitness (32%), Trudy Gaillard, Ph.D, R.N., said at a meeting sponsored by the International Society on Hypertension in Blacks.
In addition, the percentage of women in the study with a waist circumference meeting Adult Treatment Panel III (ATP III) criteria for metabolic syndrome was 31% in the moderate fitness group, compared with 84% and 64% in the low and very low fitness groups, respectively, said Dr. Gaillard of the Ohio State University Medical Center, Columbus.
The percentages meeting the high-density lipoprotein cholesterol ATP III criteria for metabolic syndrome were 46% in the moderate fitness group, and 57% and 60% in the low and very low fitness groups, and the percentages meeting the systolic blood pressure ATP III criteria for metabolic syndrome were 7% in the moderate fitness group, and 36% and 21% in the low and very low fitness groups.
The prevalence of metabolic syndrome and the individual components of the syndrome varied by aerobic fitness level for all components of metabolic syndrome except serum glucose and triglycerides.
Assessments were made using fasting and 2-hour postprandial serum glucose, insulin, and C-peptide levels obtained during an oral glucose tolerance test. Insulin resistance was measured by the homeostasis assessment model, and aerobic fitness was empirically categorized based on VO2 max, with VO2 max less than 21 mL/kg per minute considered very low aerobic fitness; VO2 max between 21 and 24.4 mL/kg per minute, low aerobic fitness; and VO2 max greater than 24.4 mL/kg per minute, moderate aerobic fitness. Moderate aerobic fitness is roughly the equivalent of brisk walking for 30 minutes a day, Dr. Gaillard said.
Findings from other studies link reduced levels of physical fitness and increased levels of sedentary activity to increased risk of metabolic syndrome. Still other studies suggest a sedentary lifestyle doubles the risk of cardiovascular disease, and that an active lifestyle halves the risk of hypertension.
African American women have been shown in studies to have the highest levels of inactivity. They also expend less energy during exercise, regardless of weight, suggesting that more exercise is needed to achieve the same benefits seen at lower levels in other populations, Dr. Gaillard noted, adding that health care providers should encourage moderate physical activity in all African American women, regardless of their level of obesity, physical activity, or risk for comorbidities.