Diet for Marathon Runners – Fluids

Why do you need fluids?

Did you know that about 60% of your body is water?

Fluids are essential to regulate your body’s temperature, transport nutrients and oxygen around your body and act as a medium for reactions to occur.

By drinking adequate volumes of fluids you can meet water needs and:

  • Reduce the risk of heat illness.
  • Improve your performance by preventing or reducing dehydration.
  • Provide a convenient way of consuming carbohydrates.

Dehydration impairs the ability of your heart to work harder and your body to regulate temperature, leading to reduced performance. Dehydration also affects mental function and coordination important for peak performance.
Did you know that sweating is one of the ways your body keeps cool? As an athlete your body adapts and sweats more, improving your temperature regulation. It is good to sweat!

Your body is not good at telling you when you need to drink during exercise. By the time you feel thirsty you are already dehydrated. You need to have a plan to maintain your fluid intake.

Using a fluid plan during your training will influence how well you can train and will give you the opportunity to practice your fluid plan for competition. You cannot train your body to get used to dehydration! You can train yourself to drink fluids regularly before, during and after exercise to prevent dehydration.

Fluid loss of only 2% of body weight can reduce your performance by up to 20%.

It is essential to ensure that you maintain your fluid balance by drinking at least eight 250ml glasses of fluids each day. Water makes up about 60% of your body and is part of all the cells in your body.

More fluids are required in hot weather and during exercise.

Excess water is not stored and thus you must replace water on a regular basis to prevent fluid imbalance.

How much fluid do you need?

Baseline fluid needs: as least 2 litres each day. This is about six to eight cups (a cup usually contains 250 ml of fluid).

Before training: drink as much fluid as is comfortable (30-500 ml). In the 10-15 minutes before you train, your urine should be pale.

During training: you need to drink the same amount as your body is losing. Fluid loss tends to be very individual. Your fluid intake should be spread out over the hour, for example, 250 ml every 15 minutes.
Work out your exact fluid needs by weighing yourself before you exercise and then again after you exercise. A 1 kg loss in weight means you have lost about 1 litre in sweat. Record the amount of fluid you drank while exercising and add to the amount of fluid lost. This is the total volume of fluid you need for similar training sessions. Weigh yourself in light clothing with sweat dried off to make the results more accurate. Use the same set of scales on a firm surface.
Follow the example below then work out your fluid need during training:
Example: You had a 90 minute training run.

    • Your weight before training was: 85 kg
    • After training your weight was: 84.25 kg
    • So you lost: 0.75 kg during training (750 ml fluid)
    • You had half a drink bottle of water during training: 450 ml
    • Total sweat loss = 1200 ml (1.2 kg)
    • % body weight lost = 1.2 kg/85 kg x 100 = 1.4%

So for similar training sessions you need to drink 1200 ml of fluid. You should try and spread this over the session, for example, 200-250 ml every 15 minutes.

What about your fluid needs after training?

After you exercise you need to drink the equivalent of 1.5 times the amount of body weight you have lost to restore fluid balance. This allows for the fluid that you continue to lose due to urination. You can use your weight before and after exercise to work your recovery fluids out.
Follow the example and then work out your fluid needs after training:
Example: You decide to have two training runs in one day.

    • Your weight before your first session was: 65 kg
    • Your weight after your first session was: 63.9 kg
    • Total fluid loss = 1100 ml sweat during training (1.1 kg)
    • % body weight lost = 1.1 kg/65 kg x 100 = 1.7%

To fully replace fluid losses before your next training session you need to drink 1650 ml (1100 ml (fluid lost) x 1.5 = 1650 ml)

Hints to help you replace your fluid losses after training:

    • Have drink bottles ready with the volume of fluid you need to replace losses and start drinking these as soon as you finish your session.
    • Have a variety of drinks, for example, one drink bottle with cold water and another with a sports drink.
    • Ask one of your training partners, friend or family to remind you to drink.

Which fluids are the best?

There are many fluids available to athletes. Consider what you need the fluid to do, as well as the taste, price, stomach comfort and availability, then choose the most appropriate drink.
To learn about a sports drink that increases your endurance by helping preserve your glycogen stores and burn your body fat for energy click here

Sports drinks

For high intensity exercise, competition or when training for longer than one hour, a sports drink provides carbohydrate as well as keeping you hydrated. Sports drinks are specifically designed to replace fluid, carbohydrate and sodium loss, efficiently during exercise.

A sports drink with 4-8% (40-80 g/l or 4-8 g/100ml) carbohydrate and 500-700 mg/l (20-30 mmol) sodium is generally recommended. Most sports drinks contain recommended carbohydrate levels, but not all meet or are close to meeting the recommended sodium content. So when choosing a sports drink, pick one that is close to the recommended sodium levels and meets your specific needs. For long distance events like marathons (and especially ultramarathons) and in extra heat it is best to choose a sports drink with the recommended sodium levels to guard against hyponatremia (an imbalance of body water and sodium).

Drinks with higher levels of carbohydrate can increase the risk of dehydration as they reduce fluid absorption.
Try different sports drinks, as there are many brands with different flavors and compositions.
To read more detailed information on sports drinks click here

Did you know that sodium has several important roles in sports drinks?

    • Enhances glucose and water absorption from the gut.
    • Maintains fluid balance.
    • Enhances fluid retention (ie: you don’t urinate as much).
    • Makes you want to drink more, which is good!

What is Sodium?
Sodium is a mineral, an essential nutrient found in most of the foods we eat. The largest source of dietary sodium comes from sodium chloride or table salt. It helps to maintain blood volume, regulate the balance of water in the cells, and keeps nerves functioning. The kidneys control sodium balance by increasing or decreasing sodium in the urine. One teaspoon of salt contains about 2,300 milligrams of sodium, more than four times the amount the body requires per day.
Most Americans consume far more sodium than their bodies need. Many foods contain sodium naturally, and it is commonly added to foods during preparation or processing or as a flavoring agent. Sodium is also found in drinking water, prescription drugs and over-the-counter medications.
In the United States, about one in four adults have elevated blood pressure. Sodium intake is only one of the factors known to affect high blood pressure, and not everyone is equally susceptible. The sensitivity to sodium seems to be very individualized. Usually, the older one is the more sensitive they are to salt.


Water is cheap, readily available and easily accessible. It is a good option when training for less than 90 minutes or competing for less than an hour. When training or competing for longer periods of for short intensity activity, water is not the best option as it contains no carbohydrate and very little sodium. The taste of water does not encourage people to drink and the lack of sodium promotes urination before total rehydration occurs.
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Fruit juices and cordials

Fruit juices and cordials contain 8-12% carbohydrate, which is more suited to recovery. If you use these fluids before or during exercise you should dilute them, other wise they could contribute to dehydration. The main sugar in fruit juice is called fructose. Fructose does not promote rapid fluid absorption. Fructose has to be metabolized in the liver, so it is slow to replace carbohydrate stores in muscle. Fruit juices and cordials also do not contain sodium in levels that are appropriate for hydration before, during or after exercise.

Milk and liquid meal replacements

Milk and liquid meal replacements provide carbohydrate, protein, vitamins and minerals and a small amount of fat. They have a role before and after exercise. Liquid meal replacements are usually well tolerated. They are useful for athletes who are traveling, have to start early or have only a small amount of time before their event. Athletes who get a nervous stomach before training or competition can try a liquid meal replacement two to three hours before activity. Liquid meal replacements can also be useful when an athlete is following a low energy diet, making weight or trying to gain weight.

Soft drinks

Soft drinks contain 10-12% carbohydrate. They contain almost no sodium and are carbonated. Carbonation can cause gut problems like nausea, bloating and diarrhea for some athletes. Athletes may feel full before they have had enough to drink. Some soft drinks also contain caffeine, which causes urination, increasing the risk of dehydration. Soft drinks are not optimal for promoting hydration, so if you do use these fluids before, during or after exercise, you should let them go flat and dilute them to half strength with water. Remember that diet soft drinks contain no carbohydrate, so they are not appropriate for replacing carbohydrate stores.

Caffeine-containing drinks (tea, coffee, energy drinks and some soft drinks)

Caffeine is a stimulant. It is commonly found in tea, coffee, soft drinks, cocoa, foods and some medications. The effects of caffeine vary for different people depending on their tolerance and usual intake. Caffeine promotes the use of free fatty acids as fuel, sparing muscle glycogen. It affects the central nervous system, increasing alertness, reducing perception of fatigue and reaction time. At high levels of intake, caffeine disrupts coordination and produces nervousness, insomnia and tremors. Caffeine has a diuretic affect (increases urination), which can contribute to dehydration. A large intake (10 or more cans of caffeine-containing soft drink or six to eight cups of coffee) could cause blood levels of caffeine above the International Olympic Committee’s prohibited limit.

Tea and coffee do not contain any carbohydrate unless sugar is added. Tea and coffee are not good rehydration fluids as they contain caffeine unless labeled as caffeine-free. Some soft drinks like colas and Mountain Dew contain caffeine.

Energy drinks

Energy drinks (eg: Red Bull) contain 12-15% carbohydrate, and caffeine, making them a poor choice as a rehydration fluid. Energy drinks have huge amounts of caffeine — which can be a diuretic and can even have a laxative effect,” says Leslie Bonci, MPH, RD, director of Sports Nutrition at the University of Pittsburgh Medical Center. This can worsen the dehydration often experienced with heavy exercise.

Scientific sports drinks

Scientific research in Japan a few years ago looked at the reasons behind the incredible endurance of giant hornets. It was found that a secretion of the hornet larvae, which the adult hornet fed on, was the source of this energy. The scientists broke this secretion down into a combination of amino acids, which they replicated into sports drinks (eg: Vaam, Hornet Juice, Diet Amino). The effect of these scientific sports drinks is to promote the use of fat as an energy source, preserving glycogen stores.
You can read more about Hornet Juice by clicking here, and as a visitor receive a 15% discount with free shipping.

Five Reasons You Should Drink More Water

I know you’ve heard this many times – “Drink more water!”. Yet, 99% of the people don’t heed this advice. Maybe if water was more expensive, people would pay more attention to consume enough of it on a daily basis. We are living in a dehydrated world of carbonated beverages, caffeine and alcohol. Recent research shows how important water is for your health, figure and well-being.

Reason 1: Water can cure many modern diseases According to the research, a long list of modern diseases can be practically eliminated by just drinking more water. The list includes and is not limited to: asthma, hypertension, back and joint pain, arthritis, constipation, allergies, ulcers and the list goes on and on.
Converts say: “I know it sounds crazy. I have heard many weird health theories in my life, but what interests me is the “results of following this or that advice”. The “drink more water cure” has worked for so many of my friends and me that I wholeheartedly recommend it to everyone. I cured myself of a nagging skin allergy. I have much more energy, strength, endurance and sleep much better now. I have had 100% success curing chronic constipation with my female clients. I don’t know a single person that didn’t benefit in some way by drinking more water.”

Reason 2: Water can decrease your appetite This is common sense. When you drink water, your stomach gets full and your appetite decreases. You end up eating fewer calories. If you drink water before each meal, you’ll prevent yourself from eating thousands of calories in the long run. This means you are going to be leaner.

Reason 3: Drinking water BURNS EXTRA calories When you drink water, your body burns extra calories. Drinking 18 ounces of water increases your metabolic rate by about 30% for about 40 minutes. This phenomenon is called Water Induced Thermogenesis. The total amount of extra calories burned by drinking 18 ounces of water is about 25 calories. Drinking 72 ounces of water amounts to 100 extra calories. That is a lot of calories in the long run.

Reason 4: Water may help you burn more fat and build more muscle It has been shown that dehydration decreases protein synthesis. Protein synthesis is what builds muscle. It is an energy costly process. When you suppress protein synthesis, fewer calories end up building proteins and more calories end up in your fat stores. It’s elementary: calories have two possible fates – they either get burned, or they get stored. When more of the calories you eat get burned, less will get stored.
Dehydration has been shown to decrease maximal strength. When you are stronger, you can lift more weight and that means you’ll build more muscle.

Reason 5: Your skin will look much better Nothing will improve the appearance of your skin better than consuming enough water. It’s a pity women spend so much money on skin products, while neglecting the cheapest and most effective one – water.

How much water should you drink?
The expert’s advice is simple: drink one ounce of water for every two pounds of bodyweight plus one and one half additional ounces of water for every ounce of beverage you consume containing caffeine, carbonation or alcohol. Do this every day.
As you increase your water intake you should also increase your salt intake. Don’t buy the “Sodium causes hypertension nonsense”. Restricting Sodium does not help the vast majority of people with hypertension. Clearly, Sodium is not the CAUSE of hypertension. Your body needs Sodium to hold its water stores. Even if you consume more than you need to, your body will get rid of the extra amount that you overconsumed.
Drink your water. Stay well hydrated. Stay healthy.