Christina Robilliard is a registered nutritional therapist in practice in Central London. said:
Hydration - Water, the forgotten nutrient
The human body is composed of 25% solid matter, and 75% water.
Your bones are are a quarter water. The muscles that drive your performance are three quarters water. If you dehydrate a muscle by only 3% you cause about a 10% loss of contractile strength, and 8% loss of speed. The truth is dehydration amongst athletes goes unrecognised and unacknowledged, even though the effects of dehydration during physical exercise have been well documented. A new paradigm has been presented regarding the function and role of water in human biochemistry. It is now generally believed that it is the water in our bodies that regulates all functions of the body, including the activity of all the solutes that are dissolved in it. This is contrary to the previously held belief that the solute composition is the governing factor of all biological functions of the body, i.e. the water is just the packing material. Life on earth could not exist without its unique physical, chemical and electrical qualities. Why then if water covers 70% of the planet and makes up 70% of our bodies, is chronic dehydration pandemic? Perhaps it is due to its abundance that we take it so much for granted. The most elaborate dietary regimes and costly nutritional supplementation can only work if a person is well hydrated.
When you become dehydrated a cascade of chemical events take place. Your body naturally begins to increase production of histamine. Histamine is present in all body tissues and produced by the mast cells found in connective tissue. Not only is histamine a mediator in inflammation, but it acts as a neurotransmitter, directing and operating the subordinate systems that promote water distribution to various tissues and organs. These subordinate systems involve the action of the hormones vasopressin and renin-angiotensin, as well as prostaglandins and kinins. When levels become excessively active the mucus membranes of the lungs, for example, can become irritated and in time the muscles and tissues that make up the breathing mechanism can go into spasm, resulting in severe breathing problems and at worse asthma . This in addition to long term damage to the immune system is bad news indeed for the athlete.
When the core temperature rises while training the blood that would otherwise be available for the muscles is used for cooling via respiration and perspiration. The body will do this automatically as temperature moves out of the preferred narrow range. It is this loss of water that ultimately impairs physical performance and interferes with normal cognitive function. Intense exercise can increase heat production in muscles 20 fold. Don’t be fooled by lack of thirst and not feeling thirsty. These sensors are inhibited by strenuous exercise.
Fluid replacement is a much misunderstood and frequently misguided aspect of nutrition and performance. Here are some guidelines:
Prehydrate – by drinking extra water for the 2 days preceding the event and continue up to 20 minutes before the start. Your stomach requires that much time to empty. Carbo loading will increase your water loading yield. In order to store each gram of glycogen, the body has to store 2.7gms of water. It is possible to consider yourself optimally hydrated when you urinate frequently and your urine is clear.
During performance take all the plain water you can get. This is particularly important for events of 30 minutes and over. Ideally water intake should match sweat loss and a prehydrated athlete has more water to spare, meaning better times and improved recovery. Cold water leaves the stomach far more quickly than room temperature water. Sip, don’t gulp and stay away from the carbonated drinks that slow absorption. The single most important factor that affects the rate of water emptying is its glucose content. The more glucose present, the slower the gastric emptying time. This includes commercial sports drinks containing high levels of simple sugar – don’t be fooled by the false feeling of increased energy. For events of 1.5 to 2 hours or longer some additional glucose and electrolyte support may be beneficial. Fructose is the preferred choice as it doesn’t stimulate insulin release like glucose does, and also replaces liver glycogen better.
Rehydrate – with plain, cold water, sipped, not gulped. Avoid everything in the goody bag until you are at least four glasses ahead, to avoid cramps and possible nausea. Continue to drink extra for the following 12 - 36 hours. To establish when hydration has been adequately recovered, you should weigh yourself prior to training or competing and again afterwards, ensuring you have drunk the equivalent amount of water lost. As a rough guide 1 pint of water equals 1 pound of lost weight. If you calculate water loss as a percentage of body weight, losing more than 1% of bodyweight can have serious consequences. The major electrolytes lost during exercise in sweat can be found in fresh fruit and vegetables, (including salt). Ensure you diet contains plenty of these.
The message is use water for what it is, the main component of your body and keep it as pure as possible, either bottled or filtered. Drink small regular amounts frequently. Drink your water fridge temperature. Do not rely on the thirst mechanism. Rehydrate using the one pint to one pound principle. Consider electrolyte replacement when exercise exceeds 1.5 hours. Carbohydrates store water – carbo load 6 days prior to competition. Keep dietary intake of fresh fruit and vegetables high. Where indicated appropriate testing of mineral levels can be carried out by a registered nutritional therapist.
In praise of protein
Protein is found more abundantly in the body than any other substance except water; fifty percent of the dry weight of your body is protein. The haemoglobin that carries the oxygen in your blood is protein. The structure of your genes and your brain cells is totally protein. All bodily functions from the blink of any eye to the creation of new muscle are controlled by enzymes and all enzymes are proteins. Protein is crucial for good health. The deficiency of this substance can cause poor stamina, hormonal problems, poor immune system function, lowered resistance to disease and slower recovery from training. It is vital you get it right.
Essential amounts of protein will vary with individuals and your body needs will vary as your body goes through its natural cycle of building and cleansing, training and recovery. Your metabolic / body type and your constitution will also determine your protein requirements and whether your needs can be met via a vegetarian diet or whether more concentrated sources of protein are preferred.
As protein is digested it is broken down into amino acids. There are 22 different acids, all of which must be present in the body. However, 10 of these are essential for life and must be supplied by the diet. These amino acids are used in the structure of body tissues, hormones, enzymes and antibodies (hence chicken soup being a good cold remedy!). Protein sources that contain all the essential amino acids in abundance are fish, chicken, animal meats and eggs and are referred to as ‘dense’ proteins. Small amounts of one or more amino acids can be found in beans, rice,grains,cereals and soybeans. Consequently, these are not considered "high quality" sources of proteins (some even go so far as to consider them in the wrong ratios for human nutrition) and must be eaten in combination and in abundance. Rice for example, although it feeds more than half the world, will not maintain lean tissue, one reason why rice eaters are almost all small-boned, small-muscled people. If you do combine grains and legumes your body can get sufficient of each amino acid to maintain health. However, when fighting illness or training hard dense protein is usually the better choice. The demands of an athlete exceed the normal criteria for ‘health’. During exercise, the body uses protein at a much faster rate. If you increase the intensity and duration of exercise protein needs increase even further. Tour de France cyclists require two and a half times the RDA (Recommended Daily Allowances) to stay in protein balance (allowances which have little relevance to athletes to begin with).
What is little understood by athletes is the role of protein in the regulation of blood sugar, via the hormonal system. This is called ‘glycaemic regulation’ and involves eating small and frequent meals combining a balance of carbohydrate and protein at each meal or snack at approximately 2:1 (grams or calories). This way of eating is particularly useful for hormonal support by reducing the stimulation of cortisol. Cortisol is the hormone elevated by exercise, especially excessive training and contraindicated at continually high levels in the body.
Listen to your body. Is your body is telling you your protein needs to come from higher sources? If you are taking in enough protein, are you breaking it down (assimilating it)? One of the requirements of protein is to manufacture digestive enzymes needed for protein digestion. In clinical practice I find many athletes lacking in these enzymes. If your body is telling you your protein needs to come from higher sources and you have problems digesting it, you may require some digestive aid in the form of enzymes for a while.
Once you have chosen which protein you are going to eat, the quantity as well as the quality is important. Too small an intake will cause problems already mentioned and too much (especially if not digested properly) can stress the system. It is possible to overload the system with protein and this can lead to problems of excessive toxicity, whereby the body is unable to adequately remove dangerous wastes. Trial and error will help you decide your individual needs. The key is to match your protein intake to your training programme. Superior protein supplements for those that require them are now available. My preferred form is concentrated nutrients derived from prime quality lean white fish, harvested from deep unpolluted ocean waters i.e. nature’s way or ‘food form’.
I believe that understanding how training and diet affect hormonal systems is the real key to achieving athletic performance. Athletes that compensate a low protein intake by taking in too much carbohydrate (especially refined carbohydrate) can expect constant hunger, difficulty losing body fat, decreased oxygen transport to muscle cells and decreased endurance. A profile I come across frequently in my practice. The truth is a high carbohydrate, low protein diet has adverse hormonal effects.
Think of food as a modulator of hormones and exercise and food go hand in hand. If the 2:1 protein to carbohydrate ratio is maintained for 5-7 days the body has the time period to make the appropriate hormonal adjustment. When your body is in balance you will experience exceptional health and peak performance. Food is not just a modulator of hunger – it is your medicine and your ticket to good health. The simple truth is that if the proteins you eat are poor quality then all the structures of your body will be poor quality. You need optimum levels of protein to build optimum structure and body proteins are not there forever, they die and need to be replaced.
I'm hoping it will become a thread for people to throw together some useful ideas. I am by no means an expert, and I would always advise people to research a sport before taking it up. The advantage of running is that it is simple, and absolutely anyone can do it.
