Want To Rehydrate Faster After Exercise? This May Help
There's nothing quite like that first big gulp of cold water after a tough workout.
When you've been sweating through a training session, replacing lost fluids is a no-brainer. But hydration isn't just about how much water you drink. It's also about how much your body actually holds onto.
New research1 explored whether protein-containing beverages could give the body an extra hand with fluid recovery after exercise, offering a fresh perspective on what makes a good post-workout drink.
About the review
The goal of the review was to understand whether protein-containing beverages could help the body recover fluids lost through sweat.
It analyzed 16 studies involving 205 participants that compared protein drinks, including milk, whey, and casein beverages, with alternatives such as water and carbohydrate-based sports drinks.
In most of the studies, participants exercised enough to become dehydrated, then drank one of the test beverages. The studies then measured how much fluid participants' bodies retained and how much they lost through urine.
This matters because effective rehydration is especially important after heavy sweating, particularly when there's limited recovery time before the next training session.
Protein drinks helped the body retain more fluid
Across the studies, participants who drank protein-containing beverages retained more fluid than those who consumed the comparison drinks. They also produced less urine, suggesting their bodies held onto more of the fluid they consumed.
Protein beverages were also associated with better overall fluid balance (the difference between fluid intake and fluid loss) and a modest increase in blood volume.
There are a few possible explanations. Protein may slow how quickly fluid leaves the stomach, allowing it to move through the digestive system more gradually.
It may also help the gut absorb sodium, an electrolyte that plays an important role in regulating fluid balance and helping the body retain water.
Together, these effects could make protein-containing beverages useful for replenishing fluids after exercise.
What this means for muscle recovery, too
There's another potential perk here.
Protein is already well known for supporting muscle repair and recovery after exercise, so getting it alongside fluids could help address two post-workout needs in one drink.
However, there are some important limitations.
Only 17.1% of the 205 participants were female, so it's not yet clear whether women experience the same hydration benefits.
Practical considerations matter, too. Milk-based drinks may be less appealing than traditional sports drinks for some people. They can also require refrigeration, making them less convenient to carry around.
How to work protein into your hydration routine
If you're already thinking about what to eat or drink after a workout, adding protein to the mix may have an extra benefit. Here are a few ways to put that into practice:
- Reach for a protein shake: If you already drink one after training, a milk-based or whey protein shake may offer the added benefit of helping your body retain fluids.
- Keep drinking water: Don't swap out your water bottle for a protein shake. Continue drinking fluids after exercise to replace what you've lost through sweat.
- Consider your schedule: Rehydrating efficiently matters most after a sweaty session, especially when you don't have much time to recover before your next workout.
Protein drinks aren't essential for rehydration, but they may be a convenient way to combine two recovery priorities.
The takeaway
Your protein shake could be earning its place in your gym bag for another reason.
Beyond supporting muscle repair, it may help your body hang onto more of the fluids you drink after exercise. Keep it alongside your usual fluids, not in place of them.
