The effect of high-salt diet intake on muscular exercise ability in young Japanese women.

This study was designed to test whether high-salt diet intake has some acute impaired effect to the muscular exercise ability due to the calcium deficit in muscle cell via the accelerated sodium-calcium exchanger. Six healthy young Japanese women (aged: 22.3 +/- 1.9 yr) performed two types of muscle strength tests and ramp mode cycle ergometer exercise until exhaustion after normal- (NaCl is approximately 5.6 g) and high-salt (21.0 g) controlled diet intake on two separate days in random order. The urinary sodium excretion sampled during 12 hours on the high-salt diet day was significantly higher compared to that of normal-salt diet day (3301 +/- 992 vs 1595 +/- 540 mg; P < 0.05), while there was no substantial difference between the urinary calcium excretion in high- and normal-salt diet days (58.6 +/- 19.7 vs 55.0 +/- 17.2 mg; ns). There were no significant differences in back strength, repeated maximal hand grip exercise ability, and VO2max and duration time during ramp exercise between high- and normal-salt diet conditions. It was concluded that high-salt diet intake even exceeding 20 g per day had substantially no acute effect on muscular exercise ability in young Japanese women.