Sodium intake and post-exercise rehydration in man
Maughan RJ, Leiper JB
Published in Eur J Appl Physiol Occup Physiol, Vol. 71 (4), pp. 311-9
Methodology
Randomised crossover in six healthy men dehydrated by 1.9% of body mass with cycling in the heat (32 °C). After exercise each drank 1.5 times the fluid lost as one of four drinks identical except for sodium: 2, 26, 52 or 100 mmol/L. Urine and blood were followed for 5.5 hours.
Key Findings
Urine output fell as drink sodium rose. By the end, subjects were still about 689 mL short on the 2 mmol/L drink and 359 mL short on 26 mmol/L, but roughly back in balance on 52 mmol/L (-2 mL) and 100 mmol/L (+98 mL).
Conclusions
The share of a rehydration drink that the body keeps is directly related to its sodium concentration.
Limitations
Only six men; laboratory setting; the higher sodium levels (52-100 mmol/L) are above most sports drinks and some find them unpalatable.
Supplements Studied
the fraction of the ingested fluid that was retained was directly related to the sodium concentration
Outcomes Measured
the fraction of the ingested fluid that was retained was directly related to the sodium concentration
the fraction of the ingested fluid that was retained was directly related to the sodium concentration
Study Details
Access Study
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