How to stay hydrated

Water is the drink of life – it makes up 70 percent of our bodies and aids in practically every one of our bodily functions, from transporting nutrients to keeping our brains focused. When we exercise, water cools our bodies down by carrying heat to the surface of our skin and releasing it through sweat. But if you’re dehydrated, your natural cooling system is disrupted, sapping your energy and putting you at risk for injury. Here’s how to keep your body quenched.

Always start your workout hydrated—that includes getting fluids throughout the day. Then replenish lost fluids during and after your workout, says David Brooks, a sports-medicine physician in Summerland, B.C. and fluid/electrolyte expert for the Canadian Academy of Sports Medicine.

Before: Drink about two cups of fluid at least two hours before exercising. This’ll allow time for your body to absorb the fluid and for your urine output to return to normal before you start to work out.
During: Drink half to three-fourths of a cup (about three to six good gulps) of fluid every 10 to 15 minutes while you’re walking, especially if your workout is strenuous and the weather is hot. Watch for the warning signs of hydration: If you have muscle cramps, a headache or feel dizzy, weak or queasy, sit down and drink more.
After: Replace all the fluid you lose during exercise to speed your recovery and return to a hydrated state. How do you know if you’ve had enough to drink? The urine test is a good gauge. “If you’re going fairly frequently and it looks like mild lemonade, then you’re well hydrated,” says Pam Lynch, Halifax-based dietitian and sports nutritionist.

If you’re walking for less than an hour, stick to water – your body doesn’t need the extra carbs and sodium found in sports drinks. But if you’re doing strenuous activity lasting over 60 minutes, sports drinks can boost your endurance. Look for brands that provide 4 to 8 percent carbs – any more will interfere with how your body absorbs fluids – and 0.5 to 0.7 g/L of sodium. And avoid the sugar-free drinks: “If you’re looking for carbs, sugar-free would be the wrong choice,” says Lynch.

Whether you’re drinking water or a sports drink, make sure it’s chilled but not ice-cold. Cool beverages empty from the stomach more quickly, making them better at hydrating your body. Ice-cold drinks, however, can be harder for your body to absorb.