Hydration
Sodium (Electrolytes)
Sodium is an electrolyte that supports fluid replacement, though scoop-sized pre-workout doses are not proven.
How it counts: Counts toward Salty only
Scored in the Salty electrolyte sub-score, not in Dose or the grade.
- Clinical dose
- 300–700 mg
- Safety ceiling
- —
- Evidence
- weak
- Category
- Hydration
Evidence summary
Research confidence: low
ACSM recommends about 0.5-0.7 g of sodium per litre of fluid during exercise lasting over an hour (1996 position stand), so 300 mg is roughly a sports drink's sodium in a scoop's worth of water. It is not a proven pre-workout dose: sodium loading improved endurance in the heat at 1.3-4.4 g taken with 0.7-1.5 L of fluid 1.5-2 h before exercise, and no trial tests 150-700 mg before a lifting session.
Research sources
- American College of Sports Medicine position stand: Exercise and fluid replacement (Convertino et al., Med Sci Sports Exerc 1996)(opens in new window)
- American College of Sports Medicine position stand: Exercise and fluid replacement (Sawka et al., Med Sci Sports Exerc 2007)(opens in new window)
Current ACSM stand: prehydrate several hours before exercise and individualize fluid and electrolyte plans; the abstract gives no per-litre sodium figure
- Ingestion of sodium plus water improves cardiovascular function and performance during dehydrating cycling in the heat (Hamouti et al., Scand J Med Sci Sports 2014)(opens in new window)
10 trained cyclists, 33 C: ~1.3 g or ~2.6 g sodium with ~700 mL water 90 min before exercise preserved plasma volume and improved time trial 7.4%; the lower dose was as good as the higher
- The effect of pre-exercise oral hyperhydration on endurance exercise performance, heart rate, and thermoregulation: a meta-analytical review (McCubbin & Irwin, Appl Physiol Nutr Metab 2024)(opens in new window)
Sodium or glycerol hyperhydration (litre-scale fluid): time to exhaustion g=0.31, time trial g=0.25