Is milk a good rehydration option?

A new study suggests that milk-based products rehydrate with greater efficiency than beverages custom-designed for the task

Milk-based beverages can be more effective than traditional sports drinks at replacing fluid lost during exercise, according to a study by Griffith University, one of Australia’s leading sports universities.

The study compared the rehydration potential of different milk-based drinks to a carbohydrate-electrolyte beverage. It claims that Pauls brand full cream milk, So Good brand soy milk, Nestle milk-based liquid meal supplement and Sustagen Sport, were more effective rehydration options than Powerade.

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The research, which is published in the Applied Physiology, Nutrition and Metabolism, observed 15 “recreationally active” men, who had to ride stationary bikes in heavy clothing to encourage sweat loss.

Each participant cycled at 70 to 80 per cent of their age-predicted maximum heart rate, until 1.8 per cent of their initial body mass was lost. They then had to consume one of the four beverages, in volumes equivalent to 150 per cent of their body mass loss, over the course of an hour. Blood and urine samples were then taken and body mass and gastrointestinal tolerance was measured over a four-hour resting period.

While the milk-based products had no impact on thirst, research did discover that the net body mass was “significantly less” in participants that drank Powerade.

The researchers believe this “superior fluid recovery” experienced by those who drank Sustagen Sport was attributed to the product’s “additional energy, protein and sodium”, which are components that have previously demonstrated a capacity to positively influence post-exercise fluid retention.

However, those that consumed milk and Sustagen Sport reported bloating and fullness more than the traditional sport drink.

The study concluded that this investigation further demonstrates the capacity of commercially available milk-based beverages to enhance the replacement of lost fluid following exercise, in comparison with carbohydrate-electrolyte drinks.

It’s worth noting that new research has indicated that dehydration doesn’t have as much of an impact on performance as previously thought. However, it’s very important we replace the fluid we have lost, to keep the body’s core temperature at its optimum, and avoid overheating.

More research is needed to see just how much of an impact certain milk products have on rehydration and whether the body is utilising such fluids or instead, just storing them. But milk is still a very effective drink to have after cycling, as it’s high in protein and will help initiate the recovery process.