Genomic and non-genomic effects of aldosterone on the individual variation of the sweat Na+ concentration during exercise in trained athletes.

To clarify whether the resting background effects (genomic) or exercise-related action (non-genomic) of aldosterone (ALD) is primarily affected to an individual variation in the sweat Na+ concentration ([Na+]sweat), we analyzed the cross-sectional relationship between [Na+]sweat and the plasma ALD concentration during rest and exercise in a hot environment. Eleven college-aged male subjects with a mean maximal oxygen uptake of 48 (range 42-59) ml kg-1 min-1 performed three sessions of 20-min cycle exercise at two levels of intensity (40 or 60% VO2max) in a room maintained at 31 degrees C. The chest sweat rate (SRch) and its containing Na+ were higher and individual differences in SRch and [Na+]sweat were greater at 60% exercise than at 40% exercise.