Recent studies have reported positive cardiometabolic responses when prolonged sitting is broken up with brief, bursts of vigorous activity termed “exercise snacks”. However, the mechanism underlying the potential health benefits of exercise snacks remain unstudied. Exercise-induced muscle contractions can promote the release of myokines that contribute to muscle remodeling and systemic cardiometabolic adaptations through inter-organ signaling. This study aimed to profile the effects of stair-climbing exercise snacks on secretion of six established myokines in young normal-weight males and adults living with overweight or obesity. In two separate randomized crossover studies, 11 young normal-weight men (NW; study 1) and 8 adults with overweight/obesity (OW; study 2) completed two experimental conditions: (i) sedentary (SED; 9-h sitting) and (ii) exercise snacks (SS; 15–30 s stair-climbing once per hour). The same high-glycemic index meals were consumed at 0, 3, and 6 h at each condition. The primary outcome was the changes in circulating myokines levels before and after the 9-h. Changes in circulating apelin levels from baseline to 9-h were higher in the SS condition compared to SED in both NW (SS: 102.2 ± 223.7 pg/mL, SED: -59.9 ± 131.6 pg/mL; P < 0.05) and OW (SS: 46.4 ± 85.3 pg/mL, SED: -120.3 ± 194.2 pg/mL; P < 0.05) groups, with no apparent difference between groups. Plasma concentration of other myokines remained unchanged across 9-h in SED and SS in both groups. Hourly stair-climbing exercise snacks did not induce clear alterations in most measured myokines, whereas apelin levels were elevated across the day compared with prolonged sitting in both groups.
Fujie et al. (Fri,) studied this question.