There is no dispute that proper hydration is critical to our body functions. But what is proper hydration? Not enough water leads to dehydration – too much water leads to over-hydration or hyponatremia. Both conditions can be very dangerous. Eight 8-ounce glasses (2 liters) of fluid per day is a good guide, but will not work for everyone. We live in different climates, exercise at different rates, have different body weights and so on. There are many factors that impact our hydration. Thirst is a poor indicator of hydration as there is a time delay between getting dehydrated and experiencing thirst. So, how do you decide? If you are serious athlete – your coach and sport dietitian should guide you. But for many of us, a simple guide published on The Academy of Nutrition and Dietetics Foundation website will do.
Web site suggests practical ways to monitor hydration:
- Urine color. The color of the first morning’s urine after awakening is an indicator of hydration status. Think pale lemonade, not apple juice.
- “Daily body weight: Daily monitoring of body weight is useful for measuring fluid balance because total body water does not fluctuate significatly under normal conditions.
- Sweat loss. Change in body weight before and after exercise is useful to estimate sweat loss. Each pound of body weight lost after exersise amounts to 16 ounces of sweat, and to rehydrate, you need 16 to 24 ounces of fluid, according to Professor R.H. Anding. Director of Sports Nutrition at Baylor College of Medicine.
If you know you are experiencing high sodium losses during exercise (think salty skin, white sweat marks on clothes), you will need to replace sodium loss with a salty snack in addition to replacing fluid.
Read more at eatright.org