HRV Alterations During Delayed-Onset Muscle Soreness Inducing Exercise – with Piezo2 Interpretation

Heart rate variability is often modulated by pain therefore our aim was to assess whether delayed-onset muscle soreness inducing exercise bout is affected by HRV alterations despite the evolvement of pain post exercise. We hypothesized the acquired Piezo2 channelopathy as the primary damage of DOMS according to a recent neurocentric theory. Piezo2 is indeed involved in pain mechanisms, modulates heart rate and it is the principal mechanosensory proprioceptive ion channel. Accordingly, the current study found that HR-dependence of time- and frequency-domain parameters could be described by an exponential-like function, while entropy showed a V-shaped function, with a minimum “turning point” separated by descending and ascending intervals. The DOMS protocol upshifted the time- and frequency-domain HRV parameters in the entire HR range, contrary to sample entropy values that were systematically down-shifted, indic-ative of an upregulated sympathetic tone. The group-averaged HR dependent sample entropy function showed a nonlinear character under exercise, with values lower for higher DOMS than for the group with lower DOMS below the turning point HR, and vice versa above it. The HR-functions of the corresponding time-and frequency-domain HRV parameters showed an opposite tendency, i.e., turning from positive to negative around the turning point HR. Oxidative stress is found to be one of the most significant influ-encing factors of HRV, however not by nonlinear parameters. Since oxidative stress is implicated in the neurocentric DOMS theory due to Piezo2 channelopathy therefore we are the first to report that after all nonlinear alterations may impact HRV in a HR de-pendent manner in DOMS.