Randomized controlled trial investigating the experimental effects of reduced habitual physical activity on...

Previous work suggests that reduced habitual physical activity is unfavorably associated with cardiometabolic health. Fewer lifestyle-based, experimental studies on this topic have been conducted. Thus, the purpose of this study was to experimentally reduce habitual physical activity over a one-week period to evaluate its potential effects on cardiometabolic profile.

Young physically active adults (M_age = 21 yrs) were randomized into a Reduced Activity Group (N = 19) or a Control Group (N = 20). The Reduced Activity group engaged in baseline week of normal activity, then reduced their activity for one week (from approximately 9000 steps/day to approximately 6000 steps/day), followed by resumption of habitual activity for a week. The Control Group maintained their normal active lifestyle for two-weeks. At all time points, the following cardiometabolic parameters were assessed: systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), atherogenic index of plasma (AIP), TC/HDL-C, LDL-C/HDL-C, TG/HDL-C, non-HDL-C, and glucose.

The Reduced Activity Group, compared to the Control Group, had an unfavorable change in TG/HDL-C (F_Interaction = 4.995, P = 0.03, η²_p = 0.14). No other biomarkers were altered CONCLUSION: A one-week period of reduced activity among a young adult, active population, increased TG/HDL-C levels, with no changes observed in any of the other evaluated cardiometabolic parameters. Thus, a temporary lapse in habitual physical activity does not considerably change cardiometabolic outcomes in young, healthy physically active adults.