Rehydration

Rehydration is the process of restoring lost fluids and electrolytes to the body after a period of dehydration. Effective rehydration is not simply about drinking water. It involves replacing both the water and the electrolytes that were lost, at a rate the body can absorb efficiently. The World Health Organization developed Oral Rehydration Solution (ORS) as a low-cost, life-saving treatment for dehydration caused by diarrheal diseases, which remains one of the leading causes of child mortality globally. ORS contains a precise ratio of glucose, sodium, potassium, and other salts that maximizes intestinal water absorption through sodium-glucose co-transport. For everyday rehydration after exercise, illness, or simply a day of not drinking enough, the general approach involves consuming fluids gradually over several hours rather than all at once. Drinking 150% of the fluid volume lost during exercise is recommended for complete rehydration, because some of the ingested fluid will be lost through continued urine production. Adding a small amount of sodium to your recovery drink, or eating salty snacks with water, improves fluid retention. Foods with high water content like watermelon, cucumbers, and oranges also contribute meaningfully to rehydration. Use our calculator to figure out how much water you should aim for daily and set a consistent hydration routine to minimize the need for aggressive rehydration in the first place.