14 Apr Salt Capsules May Not Improve Exercise Performance For Endurance Athletes
Medical Research: What is the background for this study? What are the main findings?
Dr. Weiss: Public health recommendations are to keep sodium consumption below 2300 mg/day to avoid adverse health effects. However, most people in the US consume over 4000 mg/day. Furthermore, endurance athletes are often advised to add sodium to their diets to replace the sodium that is lost in sweat and are often lead to believe that the additional sodium is important for exercise performance. Clearly these recommendations are at odds with each other.
In a double-blind placebo-controlled trial, we evaluated the effect of salt capsule consumption (containing a 1800 mg sodium) on exercise performance and on thermoregulation during 2 – 2.5 hours of running or cycling. Exercise performance was not different between the salt and placebo conditions (i.e. it didn’t provide benefit or harm for performance) nor did any of the markers of thermoregulation differ, suggesting that the salt didn’t help (or hurt) the body’s ability to cool itself.
Medical Research: What should clinicians and patients take away from your report?
Dr. Weiss: There is no apparent exercise performance benefit for athletes to use salt supplements. Modest salt in the diet, within the recommended upper limit of 2300 mg/day (which would be a reduction for most people), is sufficient for most athletes and avoids the numerous adverse effects of high salt intake on health outcomes, including hypertension, coronary artery disease, stroke, heart failure, stomach cancer, osteoporosis, and even exercise induced asthma/brochospasms.
One risk that arises from very low sodium consumption during long-duration exercise (typically >4 or 5 hr), is hyponatremia, which is a life-threatening condition. However, ironically, this typically arises in people with low fitness and low sweat rates, and is most commonly caused by extreme over-consumption of water during a marathon or other long-duration event, to a sufficient extent to cause weight gain. The solution for avoiding this is to curb the water intake to allow modest water and weight loss during the event (not to exceed weight loss of >2% of body weight, otherwise heat illness becomes a risk).
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Weiss: Similar trials could be conducted to also evaluate the effects of this salt supplementation protocol on blood pressure to determine if it increases exercise blood pressure (this would be undesirable and potentially dangerous).
MedicalResearch.com Interview with: Edward “Ted” Weiss, Ph.D. (2015). Salt Capsules May Not Improve Exercise Performance For Endurance Athletes