Your body is made up of 80% H2O (water). All life on earth depends on it. Water helps with cooling and the transportation of fuel throughout the body. Therefore it is vital to be hydrated at all times.
During any activity that is even slightly strenuous, heat is generated as a by-product of energy production to fuel the muscles. This heat must be dissipated in order to stop the body’s core temperature from rising dangerously high. The body can rid itself of heat by:
- Dilating the blood vessels of the skin, this in turn increases the flow of blood to the skin and releases the heat to the environment by radiation and convection.
- The body can secrete sweat onto the surface of the skin. This requires heat calories to evaporate the moisture, therefore causing a cooling effect. In hot weather the sweat evaporates and assists in cooling the body, therefore allowing physical activity to continue. All losses in sweat must be replaced. A person can lose as much as two liters of moisture an hour, therefore staying hydrated is important.
It is not necessary to use salt tablets to replace lost electrolytes from sweating. The modern diet is already very sodium rich, excessively so in some cases. Therefore there is no vital need for extra electrolytes. The more important thing to focus on is getting enough carbohydrates, fats and proteins to repair the body without putting on weight. If you really want to replace electrolytes then normally a glass of milk or a banana will do the trick.
Loss of electrolytes in sweat depends on such factors as gender, body size, heat adaptation, fitness level, and environmental conditions. Normal healthy diets replace these with ease. Commercial isotonic drinks do help in replacing electrolytes, replenish carbohydrate stores and replace lost fluids. However many people will replace more carbohydrates from consuming the drink than what they burned off in their exercise session. Therefore it is best to avoid these drinks when trying to lose weight. The only time you need a drink supplement after exercise is if you are an athlete in training. Otherwise plain water will do the trick just as well.
Electrolytes are solutions of acids, bases or salts. Chemically, electrolytes are substances that become ions (charged particles) in solution and acquire the capacity to conduct electricity. Electrolytes are present in the human body, and the balance of the electrolytes in our bodies is essential for normal function of our cells and our organs.
Common electrolytes that are measured by doctors with blood testing include sodium, potassium, chloride, and bicarbonate.
Sodium is the major positive ion in fluid outside of cells. Sodium combined with chlorine is what we know as salt. Excess sodium is excreted in the urine. Sodium regulates the total amount of water in the body. The transmission of sodium into and out of individual cells plays a role in critical body functions. Many processes in the body, especially in the brain, nervous system, and muscles, require electrical signals for communication. The movement of sodium is critical in generation of these electrical signals. Too much or too little sodium therefore can cause cells to malfunction, and extremes in the blood sodium levels (too much or too little) can be fatal.
Potassium is the major positive ion found inside of cells. The proper level of potassium is essential for normal cell function. Among the many functions of potassium in the body are regulation of the heartbeat and the function of the muscles. A seriously abnormal increase in potassium (hyperkalemia) or decrease in potassium (hypokalemia) can profoundly affect the nervous system and increases the chance of irregular heartbeats (arrhythmias), which, when extreme, can be fatal.
Chloride is the major negatively charged ion found in the fluid outside of cells and in the blood. An anion is the negatively charged part of certain substances such as table salt when dissolved in liquid. Sea water has almost the same concentration of chloride ion as human body fluids. Chloride also plays a role in helping the body maintain a normal balance of fluids.
The balance of chloride ion is closely regulated by the body. Significant increases or decreases in chloride can have deleterious or even fatal consequences.
The bicarbonate ion acts as a buffer to maintain the normal levels of acidity (pH) in blood and other fluids in the body. Bicarbonate levels are measured to monitor the acidity of the blood and body fluids. The acidity is affected by foods or medications that we ingest and the function of the kidneys and lungs.
When hydrating with a sports drink, it is important to note that the amount of sugar and other carbohydrates they contain can actually offset your exercise completely. When looking for sports drinks you must be careful of what product you buy and when you use it.
Unfortunately there is a whole commercial scam revolving around the ‘Science of Hydration’. The only reason hydration is such a topic is because the more you are tricked into drinking, the more products a sports drink company sells. In Professor Tim Noakes’ book “Challenging Beliefs” he has an entire section of the book dedicated purely to hydration. With 40 pages of information it isn’t a quick read but the information contained within is highly important.
There are many companies who create problems to which only their product is the solution. How is it for years before powerade/energade/Gatorade came out there weren’t thousands of people dropping dead from dehydration?
Well the problem is that dehydration is not a disease. The term refers to the fact that your total body water content is reduced. When the water content in your body drops the sodium concentrations in the blood rise. The brain detects this and creates a thirst sensation to ensure you then replace these fluids. Generally you have to be in fairly extreme conditions of heat/dryness or lost at sea to die from dehydration.
Many pseudo-scientist blame muscle cramps on the lack of electrolytes. Unfortunately there is still no conclusive study showing why we actually get them. So we won’t die of dehydration, our diets already provide enough electrolytes and low electrolyte levels have not been shown to cause cramps. So then why are we still buying these drinks? Are we all suddenly in high-level athletic training?
A nasty little syndrome is cropping up in sporting events in the past few years, Exercise-Associated Hyponatraemia (EAH). This refers to when the body retains too much water. Sodium is controlled very tightly in all living things. Any major imbalance can actually cause severe health complications. When your total body water is low, the sodium levels are then high. So your brain makes you drink until the thirst is satisfied. But in those who over drink, the blood sodium levels falls too low and the cells then become waterlogged.
Not everyone who over-drinks will develop EAH; however some people are simply genetically predisposed to it. When EAH develops basically the causes cells in the body swell. The brain cells are more resistant to shrinking than swelling. When the brain swells, it blocks off the veins that drain blood from the head, increasing the swelling. Eventually blood flow into important parts of the brain is restricted including the areas that control breathing and heart rate. Either the breathing stops or the brain swells so much that it bulges out the skull by the spinal cord. This is irreversible and death occurs quickly.
Drinks companies tried to blame EAH not on excessive drinking, rather catastrophic sodium losses in “salty sweaters”. This however makes no sense as it has been proven that we evolved specifically as hot climate long distance runners. If we died every time we lost too much salt in warm weather exercise then humans would not exist. Deadly dehydration only occurs in 2-3 days in hot conditions.
The problem is heat stroke and dehydration is often thought as the same thing. However dehydration is when the total body water is low and sodium levels are high. Heat stroke can happen before any of these levels have been significantly affected. Dehydration is not caused by heat stroke nor is heat stroke caused by dehydration. Regular intake of fluids will not stave off heat stroke any more than heat stroke causes severe dehydration. Almost all cases of heat stroke in exercise comes from exercising at a high intensity during hot weather. An incorrect diagnosis can actually lead to a person’s death in extreme situations.
An easy way to see if it is dehydration is to look at the colour of the urine and ask the person if they feel thirsty or have a dry mouth. Heat stroke will present with rapid pulse and breathing as well as dry and hot skin. However EAH has nothing to do with sweat levels or thirst levels. If someone is disoriented or confused but has been drinking water, it is NOT dehydration. It could be heat stroke but then the course of treatment is to lay the athlete down and rapidly begin cooling them off. If no improvement has been found within a few minutes (15-30) then it may be EAH or another medical condition. The tell-tale sign of EAH is vomiting, especially clear liquid. You should not be nauseous from heat stroke or dehydration. This will happen when the body is severely over-hydrated. Many cases can be treated quite easily with a 3% saline solution.
Through studies that Professor Tim Noakes did, it was clear that EAH is a whole new beast. This was not dehydration or heat stroke. People were collapsing in races because of water intoxication. Athletes were not doing better due to these new company-profit inspired drinking regimes; they were almost dying from it. Dangerous heat stroke and dehydration happen very infrequently in marathon runners, yet this is the golden goose for drinks companies. Recommendations from them say any weight loss due to dehydration is to be avoided at all costs. Yet Noakes once observed a surf-ski paddler who lost 4.2kg in body weight after a 50km stage. This paddler showed a mere single degree increase in body temperature despite having lost so much fluid. His health in no way was affected.
Running only really took off in the 70’s and companies like Nike and Gatorade (well the company that bought the drink formula) began gaining momentum. In 1978 Nike decided that ‘over-pronation’ (inward rotation of the ankle joint) was the cause of many running injuries. Also conveniently they also invented anti-pronation running shoes. Gatorade is by no means the first specific hydration drink. There was a non-commercial drink out there designed to prevent cramps in US miners. However Gatorade was thought up by Dr. Robert Cade, a renal physician from Florida.
The University of Florida football coach apparently spoke to a colleague of Cade’s about struggling with players who collapsed from heat exhaustion and dehydration. His problem was players who drank too much had stomach cramps and those who took salt had leg cramps. This led to Cade create a solution of water, salt and glucose. However this early prototype tasted terrible. The Florida Gators team were given the improved taste formula a while later and went on to beat a heavily favoured Louisiana State. Thus the legend was born.
There still is scant evidence as to whether or not Gatorade specifically enhances athletic performance. It most definitely does not stop heat stroke. Yet Gatorade is now the official drink of the NFL.
The body can lose up to 40-80 mmol/L of sodium in intensive exercise, yet most sports drinks contain 20mmol/L or less. No sports drink alone would truly replace these losses anyways. Many marathon runners and triathletes compete in far hotter conditions for longer periods of time than football players. Their blood sodium levels are far lower yet they still can continue exercise without health concerns. There have been studies on athletes in 49 °C heat who drank little or no fluids. Not one of them suffered from heat stroke or life-threatening dehydration. There was also no dangerous body temperature levels recorded. In a 2000/2001 South African Iron Man Triathlon study it was found that those who had lost the most weight during the event were also the fastest finishers.
These are all crystal clear indications that there is no such thing as the science of hydration. Sports drinks don’t have enough sodium to replace all losses after exercise. People have exercised in very hot conditions with very little water, lost quite a large amount of sodium and not one of them suffered. Weight loss from fluid loss is not life threatening. And finally, the drinks industry is yet to publish a decent study as to why a sports drink is any more useful in rehydration than plain old water for sporting events. Cases of deadly dehydration are mostly seen from illness and often in small children and babies in rural 3rd world areas. The treatment? A teaspoon of sugar and a teaspoon of salt mixed in a glass boiling water, allowed to cool then fed to the patient. No multi-million dollar sponsored drink, no fancy medication. Just what you already have in the kitchen will suffice.
Currently today even the US military has amended their drinking guidelines based on the latest research on EAH. Anyone who actually understands physiology will not recommend for you to drink until your eyeballs float. Your brain’s internal automatic processes are far better than any computing system in the world. It is accurate, fast and can continue operating even when a person has been knocked unconscious. Therefore the statement that “Waiting until thirst hits is dangerous as thirst isn’t always an accurate indicator of dehydration” is misleading. We would never have survived if we lost too much sodium in sweat, nor if we did not know when we were becoming dehydrated. Everything in our physiology is designed because we ran in hot weather for long distances, hunted animals and ate protein. This led to smarter and more efficient brains which lead to more hunting and more protein-rich intelligent brains.
Thirst is the check engine light in your car. There is a very good reason it goes on. Unless there is something drastically wrong with your warning system, that light is a good indicator for you to do something. Routine minor maintenance is one thing, but you don’t need to take your car for a major service every 2 weeks for no reason. Same idea with thirst. Sip if you need to. Drink lots if your body wants lots. But do not drink liters and liters of water just because someone wants to sell you a product.
There have been 12 reported deaths from EAH. These people died from the abuse of knowledge, not from lack of it. This was not a case of the black plague killing people because nobody knew how to treat it. This is the hospital super-bug generated from too many antibiotics given to patients who didn’t really need them.
With regards to the intake of fluids:
- Drink according to thirst. The whole “6-8” glasses a day is nonsense. Only drink if you are thirsty.
- A rough guide of fluids is 400-800ml per hour when exercising, however most athletes struggle to drink more than 600ml.
Here is some sports drink manufacturer myths dispelled:
- Weight loss in sports is natural. You will be fine. So long as you are only drinking according to thirst you will be ok. After the event is done just drink as much as your body asks for.
- Your body can sense water requirements far more accurately than your conscious mind. Trust your thirst sensations.
- Fluid requirements are different for all athletes due to the activity taking place, the weather conditions, and the fitness level and body composition of the athlete. You will have to see what works for you.
- Over drinking can and will kill you. There is no need to overdo it.
There are different types of sports drinks and liquid supplements for different needs. Some athletes do in fact need them. For the average person doing low-moderate level training up to 3 times a week there is no reason to drink anything other than water, or for after an event maybe some milk. A little snack of ordinary food or even a few sugary gummy sweets will do. Coca Cola can even work for sipping at during an event to get a little glucose burst.
For different goals your hydration needs would be different too. The difference comes in with the nutrients contained within the drinks. If you want to lose weight you still need to fuel the body. Because losing weight is about building muscle, you need to feed the growth. Starving yourself only leads to fat storage and your body eating into the muscles.
I’m wary to suggest milk to everyone because many of us are not really tolerant of lactose. Many adults suffer small allergic reactions that often go unnoticed such as stuffy noses, runny eyes, itchy skin, abnormal bowel movements etc. However if you have no reactions there is no reason to discontinue using dairy. Consuming dairy products before exercise will not have any negative effects on performance as consumption of lactose has nothing to do with the production of lactate in the muscles. If you have no reactions to milk then there is no reason to not include a reasonable amount in your diet.
These sports drink supplements are only if you really need them. Again, you must only drink according to thirst and do not consume more calories in a drink than your daily energy requirements have set.
Here are some final hydration guidelines:
- Drinks chilled between 5 to 10°C are absorbed faster in the stomach and small intestine.
- Sweet drinks must not have a carbohydrate content greater than 8% or it hinders the absorption of fluids into the body.
- Always make sure you are well hydrated before exercise, but not so well you need to stop for a bathroom break.
- Try always to consume water during any activity.
- Always rehydrate within two hours of completing exercise.
- Only drink according to thirst.
1) Electrolyte deficiencies cause cramping
The reasons behind muscle cramps are still not fully understood. However the current belief in the scientific community is that cramps are not related to nutrition. Very little magnesium, potassium and calcium are lost during exercise which makes deficiencies unlikely causes of cramps. No evidence exists that any nutrient /s can prevent cramping.
Muscle fatigue is a possible cause of cramps, because fatigue disrupts the mechanisms of muscle contraction, leading to cramps. Muscles can be conditioned to tolerate the factors that cause fatigue and subsequent cramps.
Dehydration and exercising in extreme temperatures are not direct causes of cramps, but these factors increase the risk because sodium and fluid losses are high. Sodium is involved in the neuronal control of muscle contraction, therefore low sodium and fluid levels can stimulate muscle receptors causing involuntary contraction and cramps. A proper diet, adequate rest and the correct training program can limit the amount of cramping you experience.
2) Caffeine can’t cause dehydration
Caffeine and alcohol are diuretic substances. It causes increased urine production by blocking the release of the hormone ADH (antidiuretic hormone), which does not allow the kidneys to absorb water. Caffeine is found in coffee beans, tea leaves, dark soft drinks and dark chocolate.
Any diuretic can lead to fluid loss therefore caffeine can lead to dehydration. Although many types of tea and coffee have such low levels of caffeine that drinking them actually aids in hydration. Any attempt at competing with caffeine should be tested out beforehand during training. Caffeine in small amounts should not lead to a drop in performance due to dehydration.
3) Drinking fluid with a meal slows digestion
It is not necessary to drink water in order to digest food, but it may be useful. Michael Picco, MD from the Mayo Clinic points out that drinking water while you eat can help break down food. Water during a meal is not essential to food digestion, however. It does help flush waste from the intestines and may help relieve constipation. Water will not slow digestion down.
- “With all thine offerings thy shalt offer salt” (wolffmark.wordpress.com)