How much water is enough?
For a normal day, the rule of thumb is about 30-40 mL of water per kg of body weight. So, for a 50 kg—or about 130 pounds—person, you should be drinking somewhere in the region of 1.5L to 2L of water per day.
But your water needs vary quite a bit based on your activity level, the temperature and humidity, and even the foods you eat.
In fact, most of us don’t drink enough water during the day, so it’s a good idea to drink slightly more than you think you might need. But not too much more.
You might be asking, “wait a minute, it’s possible to have too much water?”
If you’re exercising and sweating a lot, it sure is. Simply put, the body has an optimal balance of water and electrolytes. If this balance shifts because you’re losing electrolytes (in your sweat) and gaining lots of water, you could create a condition called hyponatremia. This can be a dangerous situation and could mimic symptoms of dehydration (at which point forcing yourself to drink more water can do more harm!)
Surprisingly, there have been people that died from drinking too much water. A woman in California drank so much water in a radio contest, the coroner concluded she died from water toxicity.
If you are sweating a lot, it’s important to replenish those electrolytes with things like snacks high in sodium, or a sports drink.
Be careful with sports drinks though. They are really designed for heavy exertion and are high in sugars. Water should also be consumed, not just your sports drink.
So, what and how much should I be drinking during exercise?
Unfortunately, like most nutrition-related questions, the answer is “it depends.”
Individual needs vary quite a bit on the type of exercise, how much you sweat, your goals of exercising, as well as your preferences.
For moderate activity of under 2 hours or higher intensity workouts of an hour or less, you should aim to drink 2 to 4 cups of water during your activity. Then 2 to 4 cups after your workout.
For moderate activity of longer than 2 hours or high-intensity workouts of longer than 1 hour, you should drink 1 or 2 cups before the activity. During, you’ll need about 600 mL for every hour of activity and you’ll want to consider adding some electrolytes (sodium and potassium). This can be from a salty snack, or from a sports drink. You’ll also want another 600 mL afterwards.
One final tip to take-away, if you’re thinking you aren’t drinking enough water: Get a refillable bottle and fill it up once or twice per day and just keep it beside you. If it’s within reach, you’re more likely to actually drink it!
Come and visit us at Guelph Performance and grab one of our refillable bottles for a small convenience fee. Keeping hydrated is serious business!
