The only mineral that you need to replace during exercise lasting longer than three hours is sodium, found in common table salt. You do not need to take extra potassium, magnesium, or any other mineral during exercise.
The definitive studies on minerals and exercise were done during World War II. Dr. James Gamble of Harvard Medical School paid medical students to lie on a raft in his swimming pool, take various amounts of fluids and salt, and have blood drawn to measure salt and other mineral levels. He showed that you have to take a lot of salt when you exercise for several hours, particularly in hot weather.
Gabe Mirkin
Author
Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D. brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is one of a very few doctors board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology.
