What’s the story on salt?

If you are an athlete, it is very easy to get confused about sodium intake.  Doctors always tell us to limit our sodium intake, especially as we get older, due to the impact it has on increasing blood pressure. However, coaches tell athletes they need to take sodium supplements during activities to optimize performance levels.

So who is correct?  

The short answer is they are both correct.

Let’s first look at what sodium does.  Sodium is required to transport fluid through the body.  As an individual becomes active, the body temperature begins to rise. In an attempt to cool the system, the body will transport water through the skin.  If an individual does not have enough sodium to transport water through the system, the individual’s body temperature will rise, and performance will decline.  That is why coaches tell athletes to take sodium supplements.

So how much should athletes take in?  

For every pound of water weight lost during activity through sweat, athletes will lose in a range of 300 to 1,100 mg, or, on average, around 500 mg of sodium.  I find that most athletes will lose 1 to 2 ½ pounds of water weight for every hour of exercise. That would mean that most individuals will need to take in 500 to 1,250 mg of sodium for every hour of exercise.  However there are many factors that need to be determined before deciding on how much sodium should be replaced for each athlete.

Heat and humidity level play a large role in sodium loss.  The more humid and hotter it is, the harder it will be for the body to keep cool during activity; the body will continue to sweat in an attempt to maintain body temperature.  With increasing intensity, the harder the body has to work, and the more the body will sweat. Efforts at lower intensity will result in lower sweat levels, and less sodium will be needed.   An individual’s fitness level and family genetics will also play a role with sweat rate. Athletes should track fluid loss during activity or do a sweat-rate test to get a better understanding of their supplement requirements.  

What can be especially confusing is some athletes feel like they can always have a high intake of sodium for any meal, but that is not the case.  The only time an individual should supplement sodium intake is during activity. Once the activity is over, there is no need for higher sodium levels.  Individuals should try to keep daily sodium levels around 1,500 mg counting everything they eat for the day.

So, if you have an hour workout where you need an additional 500 mg of sodium, then your total daily sodium intake should be 2,000 mg for that day.  

Understanding how much you sweat and how much sodium you need from day to day will improve performance levels.  However, limiting sodium levels on days you are inactive is the best way to remain healthy.