For a typical home workout of 20 to 60 minutes, you don't need a complicated plan: drink a glass or two of water in the couple of hours before, take sips during the session whenever you're thirsty, and rehydrate with water afterwards. Sports drinks only start to matter for longer, sweatier sessions, roughly beyond an hour or in hot conditions.

Below is a practical timeline with amounts, the signs that you're getting it wrong in either direction, and how to work out your own sweat rate if you want more precision.

Why hydration matters for your workout

When you exercise, your muscles produce heat and you sweat to get rid of it. Every litre of sweat you don't replace reduces the volume of fluid in your blood, so your heart has to work harder and your body gets worse at cooling itself.

Sports-medicine guidelines, such as those from the American College of Sports Medicine, generally aim to keep fluid losses during exercise below about 2 percent of body weight. That's around 1.4 kg for a 70 kg person. Beyond that, most people notice that workouts feel harder, concentration drops and heat becomes a bigger problem. You can reach that point faster than you'd think on a hot day, which is why a little planning helps.

The good news: most home workouts are short enough that starting the session well hydrated does most of the work.

Before exercise: start topped up

Your goal is to begin the session already hydrated, not to tank up right before it.

  • Through the day: drink regularly so you're not starting from a deficit. If you're unsure what that looks like, see how much water you should drink a day.
  • About 2 to 4 hours before: have roughly 5 to 7 ml per kg of body weight, which is about 350 to 500 ml for most people. This gives your body time to absorb what it needs and pass the excess before you start.
  • Right before: a few sips if you're thirsty. A large glass just before burpees or mountain climbers tends to slosh around uncomfortably.
  • Check: if your urine is pale yellow, you're in good shape. If it's dark, drink a glass and give it a little time.

Training first thing in the morning? You've gone 7 or 8 hours without fluid, so a glass of water on waking, 20 to 30 minutes before you start, is a sensible habit.

During exercise: sip, don't chug

How much you need during a session depends on how long it is, how hard it is and how hot the room is.

  • Under 30 minutes (for example a 15-minute home workout): most people need nothing or just a few sips. Keep water nearby and drink if you're thirsty.
  • 30 to 60 minutes: take small sips during rest breaks, perhaps 100 to 250 ml every 15 to 20 minutes if you're sweating noticeably. Thirst is a good enough guide for most people.
  • Over 60 minutes, or hot and humid conditions: fluid losses add up. Keep sipping regularly, and consider a drink with electrolytes and some carbohydrate, especially if you're a heavy or salty sweater (white streaks on dark clothes are a clue).

After exercise: replace what you lost

Most of the time a glass or two of water after a home workout, and normal drinking and eating afterwards, gets you back to baseline. A meal also replaces the salt you lost in sweat.

If you sweated heavily or trained for a long time, use the scale for a more precise answer:

  1. Weigh yourself right before the workout, with minimal clothing.
  2. Weigh yourself again right after, after towelling off.
  3. Every kilogram lost is roughly a litre of fluid. Drink about 1.25 to 1.5 litres for each kilogram lost over the next few hours, because you keep losing some fluid through urine as you rehydrate.

Spread that over a few hours instead of drinking it all at once. Pairing it with a meal or snack that contains some salt and protein helps you retain the fluid and supports recovery. Our guide to rest days has more on recovering between sessions.

Water or sports drink?

For almost all home workouts, plain water is all you need. Sports drinks are designed for situations where you lose a lot of sweat and use up carbohydrate stores.

  • Water is enough: strength workouts, HIIT, circuits and cardio sessions under about an hour, in normal room temperatures.
  • Consider an electrolyte or sports drink: sessions longer than 60 to 90 minutes, hot or humid conditions, very heavy sweating, or several sessions in one day.
  • Watch the calories: a bottle of sports drink can carry a meaningful amount of sugar. If your goal is weight loss and your workout is 30 minutes, it may undo a chunk of the calories you burned.
  • Low-sugar electrolyte tablets are a middle ground if you sweat heavily but don't need the extra energy.

Find your own sweat rate (optional)

Sweat rates vary hugely between people, from roughly half a litre to two litres or more per hour. If you train long or in the heat, a quick test is useful:

  1. Weigh yourself before a typical one-hour session.
  2. Note how much you drink during it.
  3. Weigh yourself after.
  4. Sweat loss = weight lost + fluid drunk. For example, 0.6 kg lost plus 0.4 litres drunk means you sweated about 1 litre in that hour.

Repeat this in different conditions (summer vs winter, easy vs hard) and you'll know roughly how much to drink without guessing.

Warning signs to take seriously

Stop exercising, move somewhere cool and drink if you notice:

  • dizziness or light-headedness,
  • a headache that builds during the session,
  • muscle cramps together with heavy sweating,
  • nausea, unusual fatigue or confusion,
  • stopping sweating in the heat, or hot, dry, red skin.

The last two can signal heat illness, which is a medical emergency. Get help immediately if symptoms don't improve quickly after resting and cooling down. People with heart or kidney conditions, older adults and anyone on medication that affects fluid balance (such as diuretics) should ask their doctor how much to drink around exercise.

A simple checklist

  • A glass of water 2 to 4 hours before training, and another on waking if you train in the morning.
  • Water within reach; sip during rest breaks when you're thirsty.
  • One or two glasses afterwards, plus a normal meal.
  • Electrolytes only for long, hot or very sweaty sessions.
  • Pale yellow urine as your daily check.

FAQ

Is it bad to drink water during a workout?

No. Sipping water during a workout is fine and often helpful. The idea that it causes cramps or slows you down isn't supported for normal amounts. Just avoid gulping large volumes right before intense movements, which can feel uncomfortable.

How much water should I drink during a 1-hour workout?

Many people do well with about 400 to 800 ml spread across the hour, but it depends on how much you sweat. Drink to thirst and use the sweat-rate test above if you want a personal figure.

Should I drink water before a morning workout on an empty stomach?

Yes. A glass of water 20 to 30 minutes before a fasted morning workout is a good idea, since you haven't had fluid overnight.

Is coconut water better than water for exercise?

It contains some potassium and natural sugar, but for typical workouts it isn't meaningfully better than water. It's an option if you like it; it's not a requirement.