Is Plain Water Best to Hydrate?
Is Plain Water Best to Hydrate?
You want to keep your body hydrated enough to make sure all systems are functioning properly. Especially when you're exercising.
What's happening?
Sweating works by pulling water from your blood plasma and out through the skin to evaporate (which cools you down). The more you sweat, the more your blood plasma volume drops. The body starts to pull water from other spaces to keep the sweating going. As the blood gets thicker the heart has to work harder - heart rate goes up and power goes down. Core temperature goes up and that ends up in fatigue and you tail off.
Can what you drink to hydrate be making it worse?
The small intestine is where 95% of all fluid absorption happens. It's very sensitive to water and salt and works hard to keep the two in balance so the blood plasma has just the right level of osmolality (electrolyte/water balance).
What you drink needs to be a lower osmolality than your blood. If it's weaker than the blood the intestine walls let the liquid through and you increase your plasma volume. If it's too concentrated it'll do the reverse and pull water from the body into the gut - the last thing you want. Most sports hydration drinks are more concentrated than your blood plasma so they will not hydrate you - there's too much carbohydrate in them.
Plain water then?
Well, no. Plain water doesn't have any drivers. To get properly hydrated the body likes fluid co-transporters (pilots that carry fluid across the intestinal walls). Sodium and glucose are your friends and work best together.
Plain water with a meal is fine. If you drink too much during the day you'll just pee it out rather than it getting absorbed. If you want a homemade recipe for your average resting and low intensity hydration (ie you're not going up Mount Kilimanjaro this afty), try:
285ml water
1/16 tsp sea salt (a very small pinch)
1 tsp maple syrup
Here's another recipe... Runners' World
Avoid sports drinks with maltodextrin or artificial sweeteners because they won't work the same and they'll likely give you gut ache. Original Gatorade is good.