When the body fights an infection, its need for fluid intake increases significantly. The immune response often includes a fever, which elevates core temperature and triggers increased fluid loss through sweating and a higher metabolic rate. Adequate hydration supports blood volume, which transports oxygen and immune cells, and helps regulate internal temperature. Illnesses involving vomiting or diarrhea further deplete water reserves, making fluid replenishment a fundamental part of recovery.
Essential Hydration and Electrolyte Balance
While plain water is the baseline for rehydration, certain illnesses require a more specific fluid composition to restore internal balance. Water alone does not replace the minerals lost through heavy sweating, vomiting, or diarrhea. The body loses electrolytes, such as sodium, chloride, and potassium, which are essential for nerve and muscle function.
Optimal rehydration solutions take advantage of the sodium-glucose cotransport system in the small intestine. This mechanism allows water to be absorbed efficiently into the bloodstream only when sodium and glucose are present in a specific ratio. The World Health Organization (WHO) recommends an Oral Rehydration Solution (ORS) with a near 1:1 molar concentration of sodium and glucose, typically 75 millimoles per liter (mmol/L) of each. This precise balance maximizes the absorption of water into the body.
Commercial sports drinks often contain too much sugar and too little sodium, making them less effective than medical-grade ORS for significant fluid loss. The excessive sugar concentration can create an osmotic effect in the gut, drawing water out of the body and potentially worsening diarrhea. For cases involving substantial fluid loss, using a properly balanced rehydration solution is better than relying on sugary commercial alternatives.
Warm Comfort Drinks for Symptom Relief
Beyond the physiological need for rehydration, warm drinks offer comfort and practical relief from cold and flu symptoms. The heat generates steam, which helps moisten irritated nasal and throat passages, temporarily loosening thick mucus and easing congestion. Choosing drinks that are easy to digest also helps conserve the body’s energy for fighting the infection.
Clear broths, such as chicken or vegetable, are excellent options because they provide water, some sodium, and easily digestible calories without irritating a sensitive stomach. Herbal teas, including chamomile and peppermint, are naturally decaffeinated and soothing to a scratchy throat. The warmth helps reduce inflammation in the pharynx, making swallowing less uncomfortable.
Adding honey to a warm drink or consuming it by the spoonful provides a demulcent effect. The viscous nature of honey coats the irritated lining of the throat, which helps suppress the cough reflex. Research suggests that honey’s effectiveness as a cough suppressant is comparable to some over-the-counter medications.
Drinks to Steer Clear Of When Sick
When recovering from illness, certain beverages can actively impede hydration. Alcohol is strongly discouraged because it acts as a diuretic, inhibiting the release of vasopressin, the hormone that helps the kidneys conserve water. This effect leads to increased urination and accelerated fluid loss, which compromises hydration efforts.
High-caffeine drinks, including coffee, sodas, and energy drinks, have a diuretic effect that works against rehydration. Excessive intake can increase urine output, making it harder to maintain a stable fluid balance. Furthermore, the stimulating effects of caffeine can interfere with rest and sleep, which are necessary for immune function.
Sugary beverages, particularly fruit juices and sodas, should be limited when experiencing digestive upset. The high concentration of sugar can pull water into the intestines through osmosis, potentially causing or aggravating diarrhea. This osmotic effect contributes to fluid loss and makes rehydration more difficult.