The Effect of High-salt Diet Intake on Muscular Exercise Ability in Young Japanese Women

Abstract

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.