Sodium plays a key role, not only in maintaining fluid balance, but also in the absorption of nutrients in the gut, maintaining cognitive function, nerve impulse transmission, muscle contraction and in maintaining blood plasma levels.
The amount of sodium you lose through your sweat is highly variable between individuals, from as little as 200mg of sodium/liter to as much as 2000+mg of sodium/liter, mainly determined by your genes.
Many athletes underperform or struggle when training and competing in the heat or in longer endurance events, because they don’t know how much sodium they need to replace.
Pictured: Jeff Browning getting tested by Remo.