Now that the temperatures are heating up, it is time to really think about hydration. Are you drinking enough when you’re working out? Are you drinking too much? Yes, you can drink too much and cause hyponatremia – where your sodium gets too diluted. On the other end of the scale is dehydration where you haven’t drank enough. Even a slight amount of dehydration, which can be as little as 1% of your body weight and impact your body’s ability to perform the tasks you are asking of it. The amount of the impact on performance can depend on how dehydrated you become. It’s a balance between drinking enough and not too much.

How do you know if you’re drinking enough during your workouts? Measure your sweat rate. Your sweat rate tells you how fluid you lose through sweat (and maybe urine) during your workout. To measure it, all you have to do is grab a scale and weigh yourself before and after your workout – preferably nude both times. Compare your weight before and after.

If you lost weight, divide the amount lost by the amount of time you were exercising either in minutes or hours. This is the amount of fluid you lose either in minutes or hours. First things first, if you’ve lost weight you need to drink 20 – 24 ounces of fluid for each pound lost. But a pound is 16 ounces – why drink 20 – 24 ounces? This is because your body won’t absorb all the fluid you drink, some of it will be urinated out, so the extra ounces covers that loss. What should you drink? It depends on what you are eating. To get re-hydrated you need a combination of water and electrolytes (sodium, posassium, chloride). If you are eating foods that contain these minerals, water is fine. If not, consume a drink that contains electrolytes. By the way – alcohol is not a good re-hydration choice. If you’ve lost more than two pounds, you need to adjust how much you drink next time you are out. Two pounds is an OK amount to lose. More than two pounds is cause for concern. It was either really hot or you didn’t drink enough or a combination of the two.

Another consideration is if you are a “salt sweater.” Do you get a salty ring around where you sweat on your shirt or hat? When you take the tape off your handlebars, does salt drop to the floor? If so, you also need to be concerned about consuming enough electrolytes. You might consider adding an electrolyte supplement either in a drink that is higher in electrolytes or capsules. How much to add? Unfortunately, there’s not a hard-and-fast rule. Do you experience cramps during your workout? If not, I would recommend adding a small amount and see if you notice a difference. If you notice you feel better, add a little more and see if you notice a difference. The manufacturer will provide instructions about consumption minimums and maximums. If you don’t notice a difference in how you feel you might add a little more. If you don’t notice a difference or your not a salt sweater don’t spend your money.

What about if you gained weight? You should consume less fluid less time you are out. Drinking too much fluid of any kind can cause the osmotic balance in your body to shift which can cause seizures, coma and, in some cases, death.

It’s a good idea to weigh yourself before and after workouts frequently, particularly when the weather changes. You also want to stay hydrated on a daily basis. The standard recommendation of 8, 8 ounce glasses a day is just a rule of thumb. The best way to tell if you are properly hydrated is to check the color of your urine. It should be the color of pale lemonade. Darker and you’re under hydrated (or you’ve taken vitamins). Lighter and you’re probably over hydrated.

As always, I’d love any comments or thoughts.

Penny

Reference used for this article: Sports Nutrition: A Practice Manual for Professionals 4th Edition, Marie Dunford Editor. Available through the American Dietetic Association (www.eatright.org).