Aerobic fitness impacts sympathoadrenal axis responses to concurrent challenges

The combination of mental and physical challenges can elicit exacerbated cardiorespiratory (CR) and catecholamine responses above that of a single challenge alone.

This study examined the effects of a combination of acute mental challenges and physical stress on cardiorespiratory and catecholamine responses.

Eight below-average fitness (LF VO_2max = 36.58 ± 3.36 ml^-1 kg^-1 min^-1) and eight above-average fitness (HF VO_2max = 51.18 ± 2.09 ml^-1 kg^-1 min^-1) participants completed an exercise-alone condition (EAC) session consisting of moderate-intensity cycling at 60% VO_2max for 37 min, and a dual-challenge condition (DCC) that included concurrent participation in mental challenges while cycling.

The DCC resulted in increases in perceived workload, CR, epinephrine, and norepinephrine responses overall. HF participants had greater absolute CR and catecholamine responses compared to LF participants and quicker HR recovery after the dual challenge.

These findings demonstrate that cardiorespiratory fitness does impact the effect of concurrent stressors on CR and catecholamine responses.