An LCHF diet is used in treatment and prevention of diseases or improving exercise performance. However, some studies have shown that an LCHF diet diminishes bone in young rodents. Our study demonstrates that an LCHF diet impairs bone mass and some trabecular microstructure in old mice, which are similar to the previous studies using young rodents. Moreover, our study shows that an LCHF diet reduces the benefit of exercise on lumbar BMC in old mice.

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.

Low energy availability impairs bone parameters but may assist muscle adaptation from endurance training. Our study demonstrated that the combination of running and energy restriction (ER) impaired bone mineral density and bone microarchitecture in young female rats. However, running increased the cross-sectional area of type I and IIA fibers, and the levels of mitochondrial proteins in plantaris muscle under both ad libitum feeding and ER conditions in young female rats.