The biggest thing to keep in mind when trying to figure out the optimal amount of water to consume on race day is that it all depends on the individual person. However, as a general rule of thumb, consuming ml to ml of water an hour should suffice.

It can be tricky to calculate how much water you should consume during a marathon. Put a little thought into who you are as a runner and what race day will be like.

For example, consider:. Your weight. How much you sweat. How long it will take you to finish the race. What the conditions will be during the race. A good rule to follow is to try to consume around ml to ml 2 hours before the start and another ml 15 minutes before the run.

Then, make sure you continue to drink at regular intervals throughout the marathon. Girling says that you can perform your own sweat test to determine how much sweat you lose during an hour of exercise and, therefore, how much water you should be drinking to replace that. Doing the sweat test allows you to dive deeper into the optimal amount of water to consume throughout the race.

But there are still other factors and conditions to consider, like your running pace, the temperature, and your weight. To do your own sweat test, follow these tips:. Weigh yourself before you run with no clothes on and make a note of it. Bring a controlled amount of water with you on your run, around ml will do.

Run at a comfortable pace, or your typical race pace, for 60 minutes. Make sure you consume all the water you bring with you during your run. When you finish, undress, dry yourself off, and weigh yourself again. Make a note of the weight and compare it with the weight before you ran.

Anything past this point without hydrating properly can lead to issues while you run — which you want to avoid, especially during a marathon. Once you have your post-run weight, you can convert the difference into millilitres and then add it to the ml that you consumed while you ran to find your total fluid loss.

For example, if your weight difference was 0. Keep in mind that this will vary depending on the conditions you run in, so it can be worth conducting the sweat test in a few different conditions leading up to the marathon to have the most accurate picture. According to Girling, studies have shown that over-hydrating in the run-up to a marathon has proved ineffective.

The best practice, he says, is to hydrate normally in the run-up to the day of the event. Putting in some effort to stay hydrated in the 48 hours leading up to race day is often just as important as staying hydrated throughout the race itself.

If you do this, you run the risk of becoming bloated and messing with your sodium imbalance. Though check this with your GP if you have any reason to be wary of high caffeine intakes. Make sure you drink the optimal amount around an hour before the race starts. This way, you can ensure you have time to go to the bathroom if you need to and you also have time to replenish the water you might have lost.

Why long-distance runners 'hit the wall' and how to smash through it 5 min read. Runners standing in front of two fans to cool down after a marathon © ©Virgin Money London Marathon.

This is also going to work in a similar way if the weather on the day of the race is going to be a bit colder. A runner with his arms around two volunteers helping him stand up © ©Virgin Money London Marathon. There are multiple signs of dehydration and overhydration, with hyponatremia — where your blood's sodium levels are too low — being a condition that can be caused both by having too much fluid or not enough.

Average electrolyte tabs are around 0. A person handing out Red Bull cups to runners during a race © [unknown]. As well as providing electrolytes, energy drinks provide carbohydrates, which help replenish glycogen stores which generally run out after two hours of exercise , meaning you can maintain blood glucose levels and avoid ' hitting the wall'.

Getting this from a glucose-fructose mix at a ratio will improve your ability to digest it and reduce the chances of gastrointestinal distress. Water is the go-to drink throughout the day and during workouts.

Eby suggests you consider a sports drink when you exercise at high intensity for longer than 45 minutes. They contain electrolytes essential minerals such as sodium, calcium, and potassium , which are vital to bodily function.

Trial these fluids while training to discover which work well for you. Alcohol: Alcohol is a diuretic, which makes your body remove fluids at a faster rate.

Caffeine: Caffeine also has diuretic effects, but not as much as alcohol. Generally, the fluid in a caffeinated beverage offsets any dehydrating effects.

Carbonated beverages: Carbonated drinks can cause gastrointestinal distress, and your body may not absorb carbonated fluids as well as flat liquids. Eby recommends certain populations keep an even closer eye on hydration and drink additional fluids.

As we age, our bodies contain less fluid overall, our sense of thirst diminishes, and kidney function tends to decline. Therefore, older athletes are more prone to both dehydration and heat-related illness.

Exercise is generally safe for pregnant people, but they should be especially careful about hydration. They need to maintain their own hydration and that of the baby. Finally, she says, athletes who participate in twice-a-day training, such as football programs, need to be extra mindful. It can be especially challenging to maintain hydration if you work out more than once a day.

Request an appointment, or learn more about Sports Medicine at Mass General Brigham and the teams we treat. Skip to cookie consent Skip to main content Skip to alerts Skip to pause carousel. About Us Newsroom Hydration Tips for Athletes. More alert details. Hydration Tips for Athletes Contributor Sarah Eby, MD, PhD.

Jun 5, share on facebook. How much water should I drink when I exercise? You also may experience: Dark yellow urine it should look like pale lemonade instead Fatigue Less coordination or concentration Lower intensity level than usual Lower performance than expected Muscle fatigue or cramps Tips for staying hydrated Dr.

Eby recommends several hydration tips for athletes: Follow a hydration plan every day. Depending on the intensity and duration of your workouts, it may be wise to supplement with electrolytes.

Sarah Eby, MD, PhD Sports Medicine Specialist Mass General Brigham. What should I drink during exercise? Eby also recommends that athletes limit certain beverages: Alcohol: Alcohol is a diuretic, which makes your body remove fluids at a faster rate. Heightened hydration for athletes in special populations Dr.

Girling says that you can perform your own sweat test to determine how much sweat you lose during an hour of exercise and, therefore, how much water you should be drinking to replace that. Doing the sweat test allows you to dive deeper into the optimal amount of water to consume throughout the race.

But there are still other factors and conditions to consider, like your running pace, the temperature, and your weight. To do your own sweat test, follow these tips:. Weigh yourself before you run with no clothes on and make a note of it.

Bring a controlled amount of water with you on your run, around ml will do. Run at a comfortable pace, or your typical race pace, for 60 minutes. Make sure you consume all the water you bring with you during your run. When you finish, undress, dry yourself off, and weigh yourself again.

Make a note of the weight and compare it with the weight before you ran. Anything past this point without hydrating properly can lead to issues while you run — which you want to avoid, especially during a marathon.

Once you have your post-run weight, you can convert the difference into millilitres and then add it to the ml that you consumed while you ran to find your total fluid loss. For example, if your weight difference was 0.

Keep in mind that this will vary depending on the conditions you run in, so it can be worth conducting the sweat test in a few different conditions leading up to the marathon to have the most accurate picture.

According to Girling, studies have shown that over-hydrating in the run-up to a marathon has proved ineffective. The best practice, he says, is to hydrate normally in the run-up to the day of the event.

Putting in some effort to stay hydrated in the 48 hours leading up to race day is often just as important as staying hydrated throughout the race itself. If you do this, you run the risk of becoming bloated and messing with your sodium imbalance.

Though check this with your GP if you have any reason to be wary of high caffeine intakes. Make sure you drink the optimal amount around an hour before the race starts. This way, you can ensure you have time to go to the bathroom if you need to and you also have time to replenish the water you might have lost.

Why long-distance runners 'hit the wall' and how to smash through it 5 min read. Runners standing in front of two fans to cool down after a marathon © ©Virgin Money London Marathon. This is also going to work in a similar way if the weather on the day of the race is going to be a bit colder.

A runner with his arms around two volunteers helping him stand up © ©Virgin Money London Marathon. There are multiple signs of dehydration and overhydration, with hyponatremia — where your blood's sodium levels are too low — being a condition that can be caused both by having too much fluid or not enough.

Average electrolyte tabs are around 0. A person handing out Red Bull cups to runners during a race © [unknown]. As well as providing electrolytes, energy drinks provide carbohydrates, which help replenish glycogen stores which generally run out after two hours of exercise , meaning you can maintain blood glucose levels and avoid ' hitting the wall'.

Getting this from a glucose-fructose mix at a ratio will improve your ability to digest it and reduce the chances of gastrointestinal distress. At the London Marathon, for example, there are water stations every two miles starting from mile 3.

They will supply ml bottles, so you can keep an eye on exactly how much water you are drinking. On reaching the finish line, your marathon effort is over, but your hydration strategy isn't just yet.

A person handing out water bottles to a runner during a marathon © ©Virgin Money London Marathon. When you reach the finish line, your marathon effort is over but your hydration strategy isn't — not yet, anyway. Running a marathon is no doubt going to strain your body and put it into overdrive.

There is constant pressure on different joints, you use up all of your energy stores, and your muscles slowly begin to break down. This is why continuing to hydrate once the race is over is important to help reduce the possibility of injury and muscle cramps, and aid in your overall recovery.

How to run a sub-three marathon 5 min read. Running for sport, running for fun, and running for research. Everybody is going to be a bit different when it comes to implementing the right hydration strategy.

Set alarms or notifications on your smart devices as reminders throughout the day. For a mental boost, set your Alexa or Google device to remind you along with verbal, positive encouragements. Focus on your body's signals.

Be mindful of whether your body is thirsty or hungry. Sometimes we overeat because we mistake thirst for hunger.

Drink a glass of water before each meal. It will help you stay hydrated, help your body digest food better and help you feel full faster. Add calorie-free flavoring. Try fruit or vegetable infusions in your water to make it more appealing. Prepare a jug in the refrigerator to infuse overnight to make filling your water bottle in the morning easier.

Pick up a water bottle that has a built-in infusion basket for flavor on the go. Check the color of your urine. Some people check the color of their urine throughout the day to ensure it is clear or light-colored.

Dark yellow urine may be a sign of dehydration for some. Swap high sugar drinks for sparkling water or seltzer. Not only will you cut back on unnecessary sugar, but you'll be adding to your water intake.

Set a daily goal. A simple daily goal can help you stay motivated and work towards maintaining a healthy habit. Make it a challenge.

Ask your friends to join you in a healthy competition to see who meets their daily goals regularly.

The best way to know how much fluid to drink during exercise is to calculate your sweat rate to know how much fluid you are losing during activity. After sweat rate is calculated you can calculate how much you need to drink. If it is not possible to exercise for a full hour, the following equation can be used to calculate sweat rate:.

After your sweat rate is calculated you will know your fluid needs during exercise. By minimizing fluid losses during exercise you will end exercise more hydrated, thus helping to maximize performance.

Rehydration should occur within 2 hours post exercise to assure optimal rehydration. Use this calculation to adequately replace fluid post exercise, following the guidelines stated previously.

Pre exercise wt kg — post exercise wt kg x 1. The American College of Sports Medicine ACSM and the National Athletic Trainers Association NATA recommend athletes attempt to drink fluids according to the amount lost by sweat.

Since sweat rate differs for each individual based on acclimatization level, fitness, gender, protective equipment, etc. The rule-of-thumb is for athletes to consume about ml of fluid every 15 minutes during exercise.

This is enough fluid to replace an individual with one liter per hour sweat rate, however an athlete who drank this amount during practice and had a higher sweat rate would still become dehydrated over time, which is why a universal recommendation is difficult.

The first step to ensure athletes do not become dehydrated is to have the proper supplies in place. The following are KSI-suggested items to have on hand to promote hydration during sports activities. Names of common brands and retailers are provided as examples, however this is not an exhaustive list by any means.

Prices are approximate and many providers offer discounted rates for large orders. UConn University of Connecticut school of University of Connecticut. Search University of Connecticut Search UConn. A to Z Index UConn A to Z Index Site A-Z.

UConn A-Z. To get the most accurate sweat rate, the following steps should be followed: Before the workout, ensure the athlete is hydrated light colored urine.

Being dehydrated will affect normal sweat rate. Take a nude body weight before the workout. Exercise for one hour type and intensity of exercise should be similar to the conditions in which knowledge of sweat rate is needed. During the one hour workout refrain from drinking fluids as this will affect sweat rate.

If water is consumed, weigh the water before and after the workout to determine the difference. Sports drinks and electrolytes are a popular choice for staying hydrated during and after exercise.

Sodium, potassium, and chloride are the electrolytes with the highest concentrations found in bodily fluids, however these losses are relatively small , and it is likely that they can be replaced through your usual dietary intake.

Having said this, athletes undertaking ultra-endurance events where they maintain a high sweat rate for a prolonged duration are likely to experience more significant sodium and electrolyte losses so should pay more attention to replacing them.

In this case sweat sodium testing can provide an important extra component to your hydration strategy , but for the majority of athletes targeted replacement and precise hydration strategies are not necessary. It is important to understand that the concentration of electrolytes in sweat is always lower than the concentration in the blood.

T his means that water is lost much faster than electrolytes and so replacing lost fluid in sweat should be the main priority when it comes to rehydration. Studies have shown that fluid retention is largely determined by the solute content of the beverage, these solutes include electrolytes such as sodium, carbohydrates, and protein.

Therefore, drinks that contain a combination of electrolytes, carbohydrates and protein are more effective in rehydrating you compared to water. The best examples of this include drinks such as milk, milkshakes, or protein shakes.

O ther good options would be fruit juice , s ports drinks, and electrolyte tablets. Rehydration with these types of beverages has shown to result in reduced urine formation, and greater blood volume restoration. The bottom line is that water definitely i s not the best optio n when it comes to rehydration, particularly after heavy sweating.

With all this information in mind, you can now personalise your own hydration strategy to help you reach your performance goals this summer. For those undertaking events in more extreme environments, here at Loughborough Sport we can replicat e the conditions of your event in our environmental chamber to help you understand how you sweat in race specific conditions.

This will allow you to refine your race hydration strategies through sweat rate testing and sweat sodium concentration testing. Set alarms or notifications on your smart devices as reminders throughout the day.

For a mental boost, set your Alexa or Google device to remind you along with verbal, positive encouragements. Focus on your body's signals. Be mindful of whether your body is thirsty or hungry.

Sometimes we overeat because we mistake thirst for hunger. Drink a glass of water before each meal. It will help you stay hydrated, help your body digest food better and help you feel full faster. Add calorie-free flavoring. Try fruit or vegetable infusions in your water to make it more appealing.

Prepare a jug in the refrigerator to infuse overnight to make filling your water bottle in the morning easier. Pick up a water bottle that has a built-in infusion basket for flavor on the go. Check the color of your urine.

Some people check the color of their urine throughout the day to ensure it is clear or light-colored.