There isn’t one magical hour when drinking water suddenly “boosts” your metabolism, but when you drink can make staying properly hydrated easier. A good time to start is after waking, especially if you feel thirsty, since you’ve gone several hours without fluids. From there, drinking regularly throughout the day is more useful than trying to consume huge amounts at once. Your body constantly loses water through breathing, sweating, and urination, so replacing those losses gradually helps maintain normal body functions.

Another practical time is with or around meals. Water does not interfere with normal digestion, despite a common myth that it “dilutes” stomach acid. In fact, water is involved in digestion and can help soften stool. Choosing water instead of sugary drinks with meals can also reduce calorie intake, and drinking water with food may help some people feel fuller. Research has investigated water before meals for weight management, but the results don’t support treating it as a dramatic metabolism trick.

Exercise is another important window. Drinking before, during, and after physical activity helps replace the fluid lost through sweat, particularly in warm weather or during longer workouts. You may have heard that cold water dramatically speeds metabolism. Some studies have found a temporary increase in energy expenditure after drinking water, but the effect is modest and shouldn’t be viewed as a shortcut for fat loss. Your overall diet, activity, sleep, and long-term habits matter much more.

So the “best time” to drink water is really throughout the day whenever your body needs it: after waking if thirsty, with meals, between meals, and around exercise. Thirst and urine color can provide useful everyday clues about hydration. There’s also no benefit to forcing excessive amounts of water, and people with certain kidney, heart, or liver conditions may need individualized fluid advice. The real health advantage comes from staying consistently hydrated—not from following a secret drinking schedule.