Large glass of water after waking not necessary, says doctor

Drinking a big glass of water immediately after waking is unnecessary, according to Dr Vinod Xavier, consultant in internal medicine at Aster Medcity, Kochi. While a modest glass is harmless and addresses overnight dehydration, forcing down a large volume has no proven benefit, he said in an interview.

Cold or warm water makes no difference to absorption, the body regulates temperature internally. Room-temperature water is simply more comfortable. Poor daytime hydration disrupts sleep through dry mouth and headaches, but drinking too much right before bed causes frequent urination and also harms sleep quality.

Water before meals can mildly suppress appetite but is not a metabolic fat-burner. Plastic bottles left in hot cars pose a low risk from occasional exposure, and copper vessels are safe if clean and food-grade. For kidney stone prevention, a glass before bed reduces overnight urine concentration, but total daily fluid intake matters most.