Sex differences in the impact of a 12-week high intensity interval training intervention on sympathetic Transduction

Abstract

Peak diastolic blood pressure (DBP) responses to resting bursts of muscle sympathetic nerve activity (MSNA; sympathetic transduction) are inversely associated with aerobic fitness in young males, but not females. I tested the hypothesis that 12- weeks of high-intensity interval training (HIIT) would improve aerobic fitness in young, healthy adults, but only attenuate sympathetic transduction in males. Aerobic fitness (V̇ O2peak, via indirect calorimetry), as well as peroneal MSNA (microneurography), and DBP (finger photoplethysmography) were recorded for ~10-min during supine rest. HIIT improved absolute V̇ O2peak in both sexes (both, P≤ 0.004), with greater increases observed in males (P=0.004). There was no change in sympathetic transduction following HIIT for either sex (both, P≥0.523). However, nadir DBP responses following cardiac cycles absent of MSNA bursts were enhanced (more negative) following HIIT in females (group P=0.019, females P=0.016, males P=0.345). These results indicate that HIIT mediated increases in aerobic fitness did not alter sympathetic transduction in a group of younger males and females.