Purpose: This study aimed to examine ethnic differences in objectively measured physical activity (PA) and the relationship between PA and metabolic risk factors.
Methods: The analysis included 2566 participants of the Dallas Heart Study (53% non-Hispanic black, 32% non-Hispanic white, and 15% Hispanic) who wore an accelerometer for an average of 7 d. PA was assessed as mean activity counts and time spent in moderate and vigorous activity. Outcomes included body mass index (BMI), waist circumference, systolic and diastolic blood pressure, heart rate, fasting glucose, homeostatic model assessment of insulin resistance, and plasma lipid and lipoprotein levels.
Results: A higher proportion of Hispanics than either whites or blacks obtained the recommended ≥ 150 min·wk−1 of moderate PA (24%, 14%, and 10%, respectively, P < 0.0001). White males were more likely to engage in vigorous activity than other sex-ethnic groups (P < 0.05). Time in moderate-to-vigorous activity was inversely related to BMI, waist circumference, homeostatic model assessment of insulin resistance, heart rate, and positively associated with high-density lipoprotein cholesterol levels (P < 0.0001) in the combined cohort, and the relationship was similar in all ethnic groups (P interaction > 0.05). A significant inverse association between PA and triglycerides was observed in whites (P = 7.2 × 10−4). Vigorous activity was associated with greater differences in risk factors than moderate activity (for example, β = −0.30 vs β = −0.02 for BMI). Bouts lasting ≥10 min were associated with metabolic risk factors independent of <10-min bouts in the overall sample, with similar trends observed within subgroups.
Conclusions: Hispanics had higher levels of moderate activity than whites or blacks, whereas white men had higher levels of vigorous PA than other sex-ethnic groups. The relationship between PA and several metabolic risk factors was similar across ethnicities. Vigorous PA was associated with greater benefits than moderate PA.