Manipulations to the Alcohol and Sodium Content of Beer for Postexercise Rehydration

摘要

The addition of 25 mmol.L-1 sodium to low alcohol (2.3% ABV) beer has been shown to enhance post exercise fluid retention compared with full strength (4.8% ABV) beer with and without electrolyte modification. This investigation explored the effect of further manipulations to the alcohol and sodium content of beer on fluid restoration following exercise. Twelve male volunteers lost 2.03 +/- 0.19% body mass (mean +/- SD) using cycling-based exercise. Participants were then randomly allocated a different beer to consume on four separate occasions. Drinks included low alcohol beer with 25 mmol. L-1 of added sodium [LightBeer+25], low alcohol beer with 50 mmol.L-1 of added sodium [LightBeer+50], midstrength beer (3.5% ABV) [Mid] or midstrength beer with 25 mmol. L-1 of added sodium [Mid+25]. Total drink volumes in each trial were equivalent to 150% of body mass loss during exercise, consumed over a 1h period. Body mass, urine samples and regulatory hormones were obtained before and 4 hr after beverage consumption. Total urine output was significantly lower in the LightBeer+50 trial (1450 +/- 183 ml) compared with the LightBeer+25 (1796 +/- 284 ml), Mid+25 (1786 +/- 373 ml) and Mid (1986 +/- 304 ml) trials (all p<.05). This resulted in significantly higher net body mass following the LightBeer+50 trial (-0.97 +/- 0.17kg) compared with all other beverages (LightBeer+25 (-1.30 +/- 0.24 kg), Mid+25 (-1.38 +/- 0.33 kg) and Mid (-1.58 +/- 0.29 kg), all p<.05). No significant changes to aldosterone or vasopressin were associated with different drink treatments. The electrolyte concentration of low alcohol beer appears to have more significant impact on post exercise fluid retention than small changes in alcohol content.