The Summer Hydration and Electrolyte Guide: What Your Body Actually Needs When It's Hot

The summer hydration plan that prevents the headaches, low energy, and brain fog most people blame on the heat actually requires sodium, not just water. The average adult sweats 1–2g of sodium per hour of moderate heat exposure, and replacing only water dilutes blood sodium and can produce hyponatremia symptoms that mimic dehydration. A 2018 review by Saat in the Journal of the International Society of Sports Nutrition confirmed electrolyte replacement (especially sodium) outperformed water alone in maintaining performance and cognitive function during heat exposure. The summer hydration plan: 0.5–1 oz of water per pound bodyweight daily, plus 1–2g sodium and 500–1000mg potassium across the day if you're sweating regularly.

• Roughly 0.5–1 oz per pound of bodyweight, more if you're outside, exercising, or in heat. A 150-pound person needs 75–150 oz daily in summer. The bigger variable is electrolytes — drinking 100 oz of plain water without sodium replacement actually dilutes blood sodium and can leave you feeling worse than if you drank less.
• LMNT (1g sodium, 200mg potassium, 60mg magnesium per stick) is the cleanest commercial option. Redmond Re-Lyte and Liquid IV are solid alternatives. DIY: 1/4 tsp sea salt + 1/4 tsp cream of tartar + lemon in 16 oz water. Skip Gatorade — too much sugar, not enough sodium for the calories.
• Yes — hyponatremia (low blood sodium) can occur from drinking large volumes of plain water without electrolyte replacement, especially during prolonged heat or exercise. Symptoms: nausea, headache, confusion, muscle cramps. A 2015 study by Hew-Butler in Clinical Journal of Sport Medicine documented exercise-associated hyponatremia in marathoners over-hydrating with plain water. Most people see results when they apply this consistently for at least four to eight weeks
• Headaches that don't resolve with water, muscle cramps, fatigue, brain fog, dizziness when standing, and salt cravings. If you feel worse despite drinking water, you almost certainly need sodium and potassium, not more water. Add electrolytes and symptoms usually resolve within 30 minutes. Most people see results when they apply this consistently for at least four to eight weeks before judging the effect.
• Decent for potassium (600mg per cup), weak on sodium (about 250mg per cup), and high in sugar (15g). Better than plain water but worse than a real electrolyte mix. For light exercise or moderate heat, fine. For high sweat losses or endurance, you need supplemental sodium beyond what coconut water provides.