Preworkout dietary nitrate magnifies training-induced benefits to physical function in late postmenopausal women: a randomized pilot study.

To inform end points for future work, we explored the utility of preworkout (i.e., an acute dose before training) beetroot juice (BRJ) combined with exercise (BRJ + EX) to augment indices of physical function in postmenopausal women compared with exercise only (EX). A two-arm pilot study was used to compare 24 postmenopausal women following an 8-wk, circuit-based exercise intervention. Participants were randomized to BRJ + EX ( = 12) or EX ( = 12). BRJ + EX participants consumed 140 mL of BRJ 120-180 min (only) before training for 7 wk, then discontinued during the final week to mitigate carryover effects. Physical function indices were 6-min walk test (6MWT), estimated V̇o, heart rate recovery (HRR), and maximal knee extensor power (P). A treadmill task was used to measure V̇o on-kinetics wherein mean response time (MRT) coincided with the duration to reach 63% of steady-state V̇o. Results showed greater changes (Δ) among BRJ + EX participants for 6MWT distance (40 ± 23 m vs. 8 ± 25 m; = 0.003, = 1.35), ΔV̇o (1.5 ± 0.9 mL·kg·min vs. 0.3 ± 1.0 mL·kg·min; = 0.008, = 1.20), and ΔHRR (-10 ± 6 beats/min vs. -1 ± 9 beats/min; = 0.017, = 1.05). Large and medium effect sizes favoring BRJ + EX were detected for ΔP ( = 0.07, = 0.83) and ΔMRT ( = 0.257, = 0.50), respectively. In postmenopausal women, BRJ + EX appears to magnify some adaptive benefits to physical function including aerobic capacity and recovery beyond that of training without BRJ. Investigation into contributing mechanisms is needed. Though exercise training represents the principal strategy to combat age-related decline, the attendant effects of menopause weaken aspects of exercise adaptation compared with premenopausal women and age-matched men. Here we provide important initial evidence that preworkout (i.e., an acute dose before training) beetroot juice coupled with an 8-wk, circuit-based exercise training intervention may uniquely benefit late postmenopausal women by enhancing indices of physical function including aerobic capacity and recovery.