Hydration

Keep safe - Hydrate! 

Water/sweat rates

Triathlon is a sport with three legs of exercise completed outdoors in many climates, requiring athletes to think carefully about their hydration and nutrition.  Endurance athletics, even on short races, can deplete energy, fluid and electrolyte stores rapidly.  The athlete may feel perfectly fine without hydrating for a fairly long period.  The feeling of thirst may not be felt due to adrenalin and endorphins that keep the athlete performing for hours.  However, eventually, this lack of intake of water, electrolytes and/or nutrition will catch up to the athlete and once that happens, it is almost impossible to catch up without serious support, stopping the activity or in extreme cases, a hospital stay.  There are some rather serious effects of poor hydration and this blog discusses how much is required and what can happen when the athlete ignores that need and pushes themselves to go on until it's a serious situation.  

General Recommendation for athletes

Water requirements during exercise in the heat depend on fluid loss from sweating. Sweat rate is proportional to metabolic rate and can amount to 3 to 4 liters per hour or as much as 10 liters per day. Training and heat acclimatization can increase sweat rate by 10 to 20 percent or 200 to 300 ml per hour.

1 liter = ~34 OZ   one water bottle normally holds ~17 oz. 

100 ml = ~ 3 oz

1 kg = 2.2 lbs

Planning ahead and knowing how much water should be consumed on each leg is essential to a successful healthy finish.  Here are some recommendations from medical journals. 

Recommended hydration for swimmers

Ensure you drink five to seven milliliters of fluid per kilogram of body weight slowly at least four hours before exercise. For example, for a 40kg person, intake should be between 200-280 ml or for a 70kg person, intake should be between 350-490 ml.

(70 kg = 154 lbs  so that person should drink 12.6 oz or just about 1 water bottle) 

Recommended intake of water on the bike

The amount of water or electrolyte drink a cyclist needs is highly variable, which is why an individualized hydration plan is ideal. But when an individualized plan isn't available, the amount of hydration a cyclist needs tends to range between 1.2 to 2 Liters of fluids per hour of exercise.  (40 - 68 oz or 2-4 bottles of water per hour) 

Recommended intake of water on a run

About 15 minutes before a run, drink six to eight ounces of water.  (half a bottle of water) During a run longer than 1 hour, drink water at regular intervals. This varies according to your sweat rate. Those who sweat more profusely may need 16 ounces every 15 minutes. (1/2 - 1 bottle of water) 

On races longer than an hour, it is essential to add electrolytes to the water consumption.  Over consuming water without replenishment of electrolytes can result in hyponatremia.  This is when the sodium level in your blood is too low causing extra water into your cells and making them swell. This swelling can be dangerous especially in the brain, since the brain cannot expand past the skull.

Therefore it is extremely important for the athlete to consider their personal sweat rate and plan for how replenishment will occur during the race..and to follow this plan! 

How to determine sweat rate 

Formula for Calculating Sweat Rate Calculate each athlete's sweat rate (sweating rate = pre-exercise body weight - post-exercise body weight + fluid intake - urine volume/exercise time in hours) for a representative range of environmental conditions, practices, and competitions. The simplest way to get athletes to focus on their hydration needs is to teach them to compare preexercise and postexercise body weights. If the athletes lost weight, they need to drink more at the next practice. This gives the athletes immediate feedback about their drinking habits. A simple way to assess fluid means would be to weigh the athletes before and directly after activity, and then modify rehydration based on findings. If weight loss, hydrate more. If weight gain, hydrate less

Once you know your sweat rate, you can estimate the loss of electrolytes and determine a plan for replenishment.  This is especially important if you will be racing in high heat or high humidity as sweat rates increase in these conditions.  

Your coach should be able to help you with these calculations and preparing for the race conditions. 

Dehydration 

Of course prevention is the best course as it will keep the athlete functioning at peak performance levels and healthy at the finish.  However it is very important for an athlete to also know the signs (early and serious) of dehydration in case they experience these symptoms.  Knowing that dehydration is occurring can help the athlete know they need intervention.  This can also help the athlete help other athletes who may be experiencing dehydration symptoms that may not recognize the signs.  (USAT and Ironman rules allow athletes to assist one another legally) 

Signs of dehydration include:

• Headache, delirium, confusion.
• Tiredness (fatigue).
• Dizziness, weakness, light-headedness.
• Dry mouth and/or a dry cough.
• High heart rate but low blood pressure.
• Loss of appetite but maybe craving sugar.
• Flushed (red) skin. Swollen feet. Muscle cramps.
• Heat intolerance, or chills.
• Constipation.
• Dark-colored pee (urine). Your pee should be a pale clear color.

The best way to beat dehydration is to drink before you get thirsty. 

If you wait until after you're thirsty, you're already dehydrated.

Serious Problems that result from dehydration

All of the following have similar symptoms to dehydration above.  Recognizing dehydration early is extremely important because the brain function begins to slow during dehydration.  You may be unable to help yourself or recognize you are in trouble if you don't prevent or catch dehydration early.  Severe hydration shrinks the blood vessels in the brain. When there aren’t high enough fluid levels in your brain, that affects your memory and coordination.

Heat Rash, Heat Cramps and Heat Syncope  

These are the first steps in heat and dehydration problems.  If you experience any of these problems, you can likely slow down or stop temporarily in a race, re-hydrate and recover. 

Dizzyness, rash or cramping are early symptoms that should make you consider slowing your speed and getting a bit of extra hydration and electrolytes.  

Rhabdomylosis

Rhabdomyolysis (rhabdo) is a medical condition associated with heat stress and prolonged physical exertion. Rhabdo causes the rapid breakdown, rupture, and death of muscle. When muscle tissue dies, electrolytes and large proteins are released into the bloodstream. This can cause irregular heart rhythms, seizures, and damage to the kidneys.

Heat Exhaustion

Heat exhaustion is the body’s response to an excessive loss of water and salt, usually through excessive sweating. 

Heat Stroke 

Heat stroke is the most serious heat-related illness. It occurs when the body can no longer control its temperature: the body’s temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause permanent disability or death if the person does not receive emergency treatment

Protecting yourself beyond hydration

It is very important to study the weather conditions for a race.  You will be in the elements for a considerable length of time.  Knowing how to dress and what is on the course, and where can help you manage your situation and remain healthy through the race.  

Some rules: 

1. Always were a cap on the run.  

A hat can keep your brain protected and keep the head cool.  It's also easier to put cold sponges and ice on your head to cool down with a cap.  These are often on longer races at the aid stations.  

2. Know where the aid stations are

Sometimes there are aid stations every mile on the run, but sometimes they are more spread out.  Study the course, know how long you will be in the sun and where you can find help.   Biking aid stations are often 10-15 miles apart.  

3. Wear layers

Often races begin very early in the morning and can be chilly.  However, as the day progresses, the sun may come out or it could rain.  Sun will create more heat and you will need to shed clothes.  If it rains, you will need to add clothes.  (Hypothermia can be very dangerous) If it rains and then the sun comes out, the humidity and heat index can soar.  You need to be prepared for all these possible conditions and carry clothes for them, especially if you are travelling.  You may not need them but it's always better to have them if the weather changes suddenly.  

4. Have back up plans

In a pinch, plastic bags can be used to keep clothes and shoes dry in transition or be used as makeshift insulation layers on feet, hands and core.  Save your space blankets from marathons and half marathons.  These are great to carry to races, use before the swim on cold mornings or carry in your jacket or run belt in case of rain or chilly temps in late hours.