Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial

A supervised intense aerobic exercise program improves the health of individuals with metabolic syndrome (MetS). However, it is unclear whether the timing of training within the 24 h day would influence those health benefits. The present study aimed to determine the influence of morning vs. afternoon exercise on body composition, cardiometabolic health and components of MetS. One hundred thirty‐nine individuals with MetS were block randomized into morning (AMEX; n = 42) or afternoon (PMEX; n = 59) exercise training groups, or a non‐training control group (Control; n = 38). Exercise training was comprised of 48 supervised high‐intensity interval sessions distributed over 16 weeks. Body composition, cardiorespiratory fitness (assessed by V̇O2max${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}$), maximal fat oxidation (FOmax), blood pressure and blood metabolites were assessed before and after the intervention. Compared with the non‐training Control, both exercise groups improved similarly body composition (–0.7% fat loss; P = 0.002), waist circumference (–2.1 cm; P