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.