Cardioprotective effects of resistance training add to those of total activity in Americans

Abstract

BackgroundResistance training is cardioprotective independent of total activity in experimental research and is prescribed to clinical populations, but is often largely neglected at population scale. Here we determine whether these benefits are relevant to general practice. MethodsA total of 6947 Americans over 20 years old (51% male) from NHANES 2003–2006 reported resistance training and objectively tracked 1-week total activity. Activity measures were modeled as five-level predictors of objectively measured binary heart-disease risks (hypertension, dyslipidemia, overweight, and diabetes) corrected for age, ethnicity, gender, and smoking. Significance was defined as Pfor trend less than .10 that the lowest activity category differed from the average of all others. If both activity measures predicted the same risk, mutually corrected models were run. ResultsAverage total activity was 20 minutes/day (SD 24). About 30% of subjects had resistance trained in the past month, reporting up to 7 sessions/day. Prevalences of hypertension, dyslipidemia, overweight, and diabetes were 32%, 46%, 68%, and 7.2%, respectively. All significant associations for resistance training (but not total activity) exhibited a threshold in dose–response curve, with comparable benefits from any dose above “none.” Resistance trainers had significantly lower odds of hypertension (ORs, 0.55–0.85), overweight (ORs, 0.55–0.74), and diabetes (ORs, 0.51–0.80), but not dyslipidemia (ORs, 0.55–0.74). For total activity there was no significant trend in risk of either hypertension or dyslipidemia, but there were for overweight (ORs for each quintile above the lowest 1.04, 0.89, 0.78, and 0.49) and diabetes (ORs, 0.83, 0.68, 0.50, and 0.23; all Pfor trend <.01). Associations of resistance training with diabetes and obesity attenuated only slightly after correction for total activity, and vice versa. ConclusionsCardioprotective associations of resistance training were comparable to those of total activity and clinically relevant at low doses. Largest benefits accrued to those who combined any dose of resistance training with high total activity.