Solution: Athletes, especially endurance runners, need to pay attention to what and how much they're drinking before, during and after exercise. Even if the weather is cold, you still need to make sure you stay hydrated.
Here are some simple rules for drinking and exercising:
An hour before you start to exercise, try to drink 16 to 24 ounces of water or other non-caffeinated fluid. Stop drinking at that point, so you can prevent having to stop to go to the bathroom during your bout of exercise - especially if you're a runner and going on a longer run. To make sure you're hydrated before you begin to exercise, you can drink another 4 to 8 ounces right before you start.
You should take in 6 to 8 ounces of fluid every 20 minutes during your workout. During longer workouts (90 minutes or more), some of your fluid intake should include a sports drink (like Gatorade) to replace lost sodium and other minerals (electrolytes).
Don't forget to rehydrate with water or a sports drink after your workout. You should drink 20 to 24 fl oz. of water for every pound lost. If your urine is dark yellow after your workout, you need to keep rehydrating. It should be a pale yellow color.