Q. If you exercise daily (and sweat), can you have more than the daily recommended limit of sodium?
A. The simple answer is “Yes,” but it really depends on how much you exercise and sweat, and how much sodium already is in your diet. Sodium in our diet comes largely from salt (sodium chloride). You need to have enough sodium in your diet each day to keep up with the sodium you lose in your urine and sweat. It is recommended that most adults ages 50 or younger have no more than 2,300 milligrams (mg) per day of sodium. For people 51 or older, for African Americans of any age, and for people with diabetes, high blood pressure, or kidney disease, the recommended level is 1,500 mg per day.
Unfortunately, the average U.S. adult takes in about 3,400 mg of sodium per day—much more than recommended. So if you are the average adult, you need to lose some sodium each day. One of the many healthy effects of exercising is that you lose sodium in the sweat.
If you are a manual laborer working an 8-hour to 12-hour shift, you lose a lot of sodium—5,000 to 6,000 mg per day. So you can safely have more than the recommended amount of sodium in your diet. On the other hand, if you work out at the gym for 30 minutes a day and are otherwise sedentary, there is a reasonable chance that you still may be taking in too much salt in your diet. While the exercise is good for you in many ways, it isn’t a reason to increase the salt in your diet.
—Anthony L. Komaroff, M.D.
Editor in Chief
Harvard Health Letter