Post-exercise rehydration in man: effects of volume consumed and drink sodium content
Shirreffs SM, Taylor AJ, Leiper JB, Maughan RJ
Published in Med Sci Sports Exerc, Vol. 28 (10), pp. 1260-71
Methodology
Repeated-measures trial in 12 men dehydrated by about 2% of body mass with intermittent cycling. On four occasions each drank 50%, 100%, 150% or 200% of the fluid lost; six received a 23 mmol/L sodium drink and six a 61 mmol/L sodium drink. Urine was collected for 7.5 hours.
Key Findings
With the lower-sodium drink, much of any volume above sweat loss was simply urinated away; with the 61 mmol/L drink, the 150% volume restored balance better. Median urine after drinking 100% of losses was 493 mL with the low-sodium drink and 260 mL with the higher-sodium drink.
Conclusions
To restore fluid balance after exercise you need to drink more than you lost, and that extra volume is only retained if the drink contains enough sodium.
Limitations
Small groups of six per drink, men only, lab dehydration of about 2%; sodium comparison was between groups rather than within subjects.
Supplements Studied
both sodium concentration and fluid volume consumed interact to affect the rehydration process
Outcomes Measured
both sodium concentration and fluid volume consumed interact to affect the rehydration process
Study Details
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