The nutritional composition of milk, i.e. the amount of energy, fluid, protein, carbohydrate and electrolytes such as sodium and potassium, suggests that milk can be useful as a drink after exercise.
Comparisons with sports drinks with a similar osmolarity show that milk is beneficial for restoring fluid balance after exercise (1-5), possibly because of its favourable composition of electrolytes. The water and electrolytes in milk contribute to the recovery of fluid balance, while the proteins, naturally present in milk, help to repair and regenerate muscles after exercise and the carbohydrate reserves are partially replenished by lactose. (3-4,6) Additionally, the protein can stimulate muscle protein synthesis and the development of muscle mass after strength training, for both men and women in the short as well as in the longer term. (7-9)
Hydration after exercise
The aim of fluid intake is to replenish the fluid lost during exercise so it is important that the majority of fluid consumed is retained in the body rather than lost via urine. In order to provide more guidance this, Maughan et al., (2016) recently developed a beverage hydration index (BHI), which is a measure of the extent to which the body can absorb and retain the fluid from a drink. During the development of this index the effect on fluid balance of 13 different drinks, from water to milk and an oral rehydration solution (ORS) to beer, were compared. Subjects drank equal quantities of the different drinks, after which the urine volume was measured. ORS and skimmed and full-fat milk produced significantly less urine than other drinks such as water, tea, coke and a sports drink did (see figure). A lower urine production is an indication that the body can ‘use’ more fluid for recovering the fluid balance. (5)
FIGURE The Beverage Hydration Index (BHI) of 13 drinks compared to water
This figure shows the BHI of the various drinks. Here water is the standard and has a BHI of 1, a BHI of more than 1 means a higher hydration value compared to water, a BHI below 1 means a lower hydration value than water.
- Maughan R.J., Watson P., Shirreffs M. (2015). Implications of active lifesyles and enviromental factors for water needs and consequences of failure to meet those needs. Nutrition Reviews. 2015;73(S2):130-40. doi: 10.1093/nutrit/nuv051.
- Roy B.D (2008). Milk, the new sports drink? A review. Journal of the International Society of Sports Nutrition. 2008;5:15.
- Shirreffs S.M., Watson P., Maughan R.J. (2007). Milk as an effective post-exercise rehydration drink. British Journal of Nutrition. 2007;98:173-180.
- Watson P., Love T.D., Maughan R.J, Shirreffs S.M. (2008). A comparison of the effects of milk and a carbohydrateelectrolyte drink on the restoration of fluid balance and exercise capacity in a hot, humid environment. European Physical Journal Applied Physics. 2008;104:633-642.
- Maughan, R.J, Watson, P., Cordery, P.A.A., Walsh, N.P., Oliver, S.J., Dolci, A., Rodriguez-Sanchez, N.R. and Galloway, S.D.R. (2016). A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index. American Journal of Clinical Nutrition, 2016;103:717–23.
- Lee J.K.W., Maughan R.J., Shirreffs S.M., Watson P. (2008). Effects of milk ingestion on prolonged exercise capacity in young, healthy men. Nutrition. 2008;24(4):340-7. doi: 10.1016/j. nut.2008.01.001.
- Elliot T.A., Cree G.M., Sanfor P.A., Wolfe R.R., Tipton K.D. (2006). Milk ingestion stimulates net muscle protein synthesis following resistance exercise. Medicine & Science in Sports & Exercise. (2006);38:667-674.
- Hartman J.W., Tang J.E., Wilkinson S.B., Tarnopolsky M.A., Lawrence R.L., Fullerton A.V., Phillips S.M. (2007). Consumption of fat-free fluid milk following resistance exercise promotes greater lean mass accretion than soy or carbohydrate consumption in young novice male weightlifters. The American Journal of Clinical Nutrition. 2007;86:373-381.
- Wilkinson S.B., Tarnopolsky M.A., Macdonald J.R., Armstrong D., Phillips S.M. (2007). Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. American Journal of Clinical Nutrition. 2007;85:1031-1040.