Changes in urinary catecholamine, heart rate, blood pressure and double product during ascent of one-day Mt. Fuji hiking in Japanese young males

Abstract

We investigated changes in the basic parameter of physiological stress such as catecholamine and heart rate, blood pressure during the ascent of one-day Mt. Fuji hiking via the Fujinomiya Trail. Six Japanese healthy young adult males (age: 21 ± 1 years) volunteered to hike Mt. Fuji (altitude: 3,776 m) located in Shizuoka Prefecture in August 2014. The weather was fine. Heart rate (HR), arterial oxygen saturation (SpO₂), blood pressure (SBP/DBP), double product (DP), urinary adrenaline (AD) · urinary noradrenaline (NA) and creatinine (Cr) were measured at a point near sea level (Pre: altitude 9 m) and during the ascent. HR, AD/Cr, NA/Cr and DP at the summit were significantly higher and SpO₂ was significantly lower than those of Pre and 5^th Station (altitude: 2,400 m). AD/Cr and NA/Cr at the 5^th Station were significantly higher than those of Pre (values at starting point near sea level). There was no significant change in SBP and DBP. As a significant positive correlation between changes in the indices of catecholamine (AD/Cr, NA/Cr) and HR, DP was observed during the ascent of one-day Mt. Fuji hiking (p<0.05). It has become obvious that the increase in urinary catecholamine and the index of cardiac overload during the ascent of Mt. Fuji should be derived from an enhancing of adrenergic sympathetic nervous activity by barometric depression, temperature decrease, and increase in exercise intensity. In addition, enhanced adrenergic sympathetic nervous activity was caused by hypobaric hypoxia even at the 5^th Station.