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How much water do I need to run 20 miles?

Author

Emily Sparks

Published Jan 12, 2026

The general rule of thumb for fluid consumption during runs is: Take in 4 to 6 ounces of fluid every 20 minutes. Runners running faster than 8-minute miles should drink 6 to 8 ounces every 20 minutes.

How much water do I need for a 10 mile run?

I recommend carrying a water bottle with you and drinking a daily minimum of three litres (just over five pints) of water. Monitor the colour of your urine - if it is almost clear you are well hydrated. Avoid fizzy drinks, caffeinated beverages and alcohol due to their dehydrating effects.

Do I need to bring water on a 10 mile run?

How much you need to drink on the run depends on how much you sweat. "Most people sweat at a rate of 24 to 32 ounces an hour while exercising—and should aim to replace at least 75 percent of that on the run," says Antonucci. That means drinking 18 to 24 ounces an hour while running.

How much water do distance runners need?

Aim for 16 ounces (2 cups) of water at about two hours before you run. Pair this with a snack or meal. About 15 minutes before a run, drink six to eight ounces of water. During a run longer than 1 hour, drink water at regular intervals.

What do I need to run 20 miles?

Eat a high carbohydrate snack of approximately 300 calories. You may need more or less depending on your metabolism and you should have checked this out on your long training runs. Drink at least one water bottle (750 ml). Have a warm drink to stimulate the bowel, but beware of caffeine.

22 related questions found

Is it hard to run 20 miles?

Mentally speaking, it can be daunting to run 20-plus miles and the marathon distance. The secret is to break the distance into smaller, more digestible pieces. You can do this with time, distance or landmarks on the path. Once you do, your mind only has to think about the next mini-goal.

How long does a 20 mile run take?

“For example, at my long-run pace, a 20-miler will take about 2.5 hours. For someone else, that could take 4 hours. Those are two completely different levels of stress on the body!” Running coach John Honerkamp recommends capping long runs at 3.5 hours.

Should I carry water while running?

If you're doing a short run, say one that lasts 45 minutes or less, you may be able to forgo drinking water while you're out there. But it's never a bad idea to carry water, especially if it's really hot outside and you'll be sweating a lot. Many runners carry and drink water regardless of how long they'll be running.

Should you drink water during a 5K?

When participating in a 5K, whether it's running or walking, it's important to drink water. Sports drinks may also be helpful on difficult runs and on hot days. Hydration is important before, during, and after any vigorous activity.

How do you hydrate for a long run?

Water, diluted juice and sports drinks are all good fluid replacers. If you've been running for less than an hour, plain water is a good choice, but, if you have been running hard for longer than an hour, drinks containing sugar or maltodextrin (a slow-release carbohydrate) and sodium may speed your recovery.

Can you run a marathon without water?

The human body begins to lose performance with a 2% or less loss in water (per body weight). So a 150# runner can only afford to lose about 48 oz of water. Running a 3 hour marathon with no water consumption on a cold day will use about 120 oz of water or 5% which will really slow you down.

When should you start bringing water on a run?

If your run is 30 minutes or less, drinking a glass or two of water before and after the workout should be fine. For runs longer than half an hour, bring a bottle and sip throughout your run. There are running-specific handheld bottles that fit comfortably like a glove—you likely won't even notice it's there!

What to drink after running to lose weight?

Chocolate milk

Chocolate milk happens to be a perfect post-run drink. It's loaded with high-quality protein and fast-digesting carbs for muscle recovery and energy refueling. Similarly to many commercial exercise-recovery drinks, low-fat chocolate milk has a 4:1 carb-to-protein ratio ( 13 ).

How much sweat do you lose while running?

For every pint, or 16 oz., that you sweat, you will lose one pound of body weight. You will generally lose around 17 oz. during an hour run, or 8.5 oz. during a 30-minute run, says author Owen Barder in "Running for Fitness." This equals slightly over 1/2 pound.

How do you carry water while running?

Hydration packs

For a more hands-free approach, try running with a hydration pack. These can range from light vests to small backpacks that can carry a reservoir of water or hydration bladder and have a hose you can sip from while running.

How do you breathe when running?

The best way to breathe while running is to inhale and exhale using both your nose and mouth combined. Breathing through both the mouth and the nose will keep your breathing steady and engage your diaphragm for maximum oxygen intake. It also allows you to expel carbon dioxide quickly.

How much water should you run in an hour?

In general, it's recommended that athletes aim to drink 0.4-0.8 liters per hour (L/h) or 8-16 ounces per hour (oz/h).

How long should I run a day?

While these benefits can be achieved by a minimal amount of daily running, a group of Dutch researchers recommends running 2.5 hours per week, or 30 minutes, five days a week to enjoy maximum longevity benefits.

Where do runners put their phone?

These are the best phone holder for running options:

  1. In a zipped pocket of your shorts or running tights.
  2. Strapped to your arm.
  3. In your sports bra or chest pouch of a race vest.
  4. In a secure handheld device.
  5. Or in a waist belt.

Is it healthy to run 20 miles a day?

The science shows that a 20-mile long run might, in fact, be right for you, but only if your weekly mileage is around 65 miles per week and if your long run workout pace is faster than 9:00 minutes per mile. Everyone else should consider the long run the Hansons way, by factoring in weekly mileage and pace.

What happens to your body after running 20 miles?

At about 20 miles, levels of glucose in the bloodstream start to drop and the stores of carbohydrate energy in the body are almost depleted. Runners will become more aware of the distress signals that the various parts of the body are sending to the brain.

Can you walk 20 miles in a day?

A Healthy Person can walk around 20 miles in a day. In a single day, you can walk 20 miles without any problems. This is about the same distance as a marathon race, and it's a perfectly healthy thing for someone to do.

Can I run a marathon if I can run 20 miles?

If you can run 20 miles, you can run 26.2! The 20 mile long run has become a staple in most marathon training plans, regardless of overall weekly mileage or training paces. It's the hallmark of marathon training, the run which many runners consider their peak workout.

Can you run 20 miles without training?

"If you're a runner and your body is conditioned to running 5k or 10k in distance, as long as you set your goals properly and you run at a very slow pace, you could probably get around," he says. "If you walk briskly at 15 minutes per mile, that's six-and-a-half hours to do 26.2 miles - most people could sustain it."

Does running make you skinny?

Running is an excellent form of exercise for weight loss. It burns a lot of calories, may help you continue to burn calories long after a workout, may help suppress appetite and targets harmful belly fat.