When it comes to exercise, you lose water through sweat, which is a mixture of water
and salt. When you swig water
while running, you replace the water
in your body but not the salt. While it's fine for shorter runs, you may want to switch to a sports drink for longer runs. Sports drinks contain both sodium and potassium to help you avoid dehydration and sodium deficiencies, which can make you feel dizzy, tired and nauseous.