Acute Effects of Exercise on the Nephron Index under Different Conditions in Middle-Aged Males: A Preliminary Study
Shotaro Kawakami1,2, Tetsuhiko Yasuno3, Saki Kawakami4
1Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan.
Background:
The nephron index provides a noninvasive and theoretical estimate of the functional nephrons based on the assumption that serum fibroblast growth factor 23 (FGF23) concentrations correlate with phosphate excretion per functional nephron. This study aimed to investigate the effects of exercise on the nephron index under different conditions.
Methods:
Nine middle-aged adults performed exercise under 3 experimental conditions: moderate-intensity continuous exercise (MICE), high-intensity intermittent exercise (HIIE), and moderate-intensity intermittent exercise (MIIE). Blood and urine samples were collected before exercise, immediately after exercise, and 60 min post-exercise. The nephron index was assessed using blood and urine phosphate and creatinine concentrations, serum FGF23 levels, and the estimated glomerular filtration rate.
Results:
A significant time effect was observed for the log-transformed nephron index (p = 0.012,
Conclusions:
These results suggest that a single bout of exercise may influence nephron responsiveness in middle-aged individuals. However, as this is a preliminary study, further investigations are warranted to confirm the physiological relevance of the nephron index under dynamic conditions.
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