For decades doctors have prescribed a low-sodium diet for their patients because taking in too much salt temporarily elevates blood pressure. While that’s typically not a problem for healthy, athletic women like you — after all, intense exercise often has the same effect — it could be devastating for unhealthy or older people who suffer from cardiovascular problems, potentially triggering a stroke or heart attack. No wonder people have been led to believe that they should eliminate as much salt from their diets as possible.
But it turns out that the truth is much more complicated, particularly for athletes like you who may have greater needs for the electrolytes that are found in table salt, but excreted, particularly through sweat during long exercise bouts. “The average healthy woman should consume between 1,500 and 4,500 milligrams of salt per day,” says Kevin Steele, Ph.D., and vice president of education and programs for Mad Dogg Athletics. “My recommendation is to stay on the lower end of this range unless you are preparing for an endurance event and your training is consistently averaging more than 2.5 hours a day of aerobic exercise.”
For strenuous endurance exercise, you want your body to maintain more fluids. “Timing is everything,” says Kim Jackson, RN, Ph.D. “When you’re expecting to experience fluid losses from intense exercise, then you should take in an electrolyte-balanced drink that contains sodium about four hours prior to the event.” In addition, you should also get in potassium, the balancing electrolyte. Most sports products contain both of these cellular fluid regulators, but check labels to make sure.
You lose large amounts of fluids through your sweat, and electrolytes flow out with them. “The average woman loses between .4 and 1.2 liters of sweat per hour of exercise,” Jackson says. However, the sodium content in sweat varies considerably from person to person, and can range anywhere from 115 to 5,000 milligrams for every liter of sweat.
One of the biggest risks of getting in too little sodium, especially when you’re performing an endurance event or sweating excessively, is that you’ll replace fluids without also replenishing the electrolytes you’re losing. “Our bodies are constituted of 75 percent water, and 90 percent of our cells are made of water,” Steele says. The natural instinct is to take in water because you’re thirsty. “But this can lead to hyponatremia.”
This is the condition where you have too few electrolytes in your system, and taking in more water further dilutes them, leading to short circuits in the way your brain and body function. At this point, Steele says, you need to make sure you get in an elevated concentration of electrolytes in addition to fluid. Sports beverages are a better choice than water. In extreme cases, healthy athletes who experience this short-term trauma often need electrolytes administered intravenously.
The key for athletic women who want to maintain homeostasis is to take in the same amount of sodium every day. Keep in mind that taking in a very low amount of sodium (below 1,500 milligrams per day) leaves you more vulnerable to blood-pressure spikes should you inadvertently consume more than you do regularly.
If you want to present your physique in the best possible light, though, you should consume at least a moderate amount of sodium (about 2,300 to 2,500 milligrams) every day. This will allow you to cut sodium more dramatically, encouraging your body to dump more water. The net result of this strategy will be a “drier” look that shows off your lean tissue and reduced body fat more spectacularly.
This effect is temporary, and you’ll return to fluid-balance baseline as you add sodium back into your diet or your body naturally adjusts to this lower level. But this is a handy trick you can use when you want to appear leaner and more shredded for a day or two. See “Water Shed Moment” for the details on how you can maximize this temporary effect.