Water
Your body is predominately comprised of water, especially at a young age, due to low body fat and bone mass. As we get older, are percentage volume of water reduces from 70+ % to around 45%. The younger you are and greater leaner muscle mass will increase your volume of water %.
All of our bodily functions and chemical reactions occur in aqueous solution, 65% of your bodies water is found inside your cells (intracellular fluid) ICF, with the remaining 35% being found outside the cells (extra cellular) ECF.
Dehydration occurs when fluid loss exceeds intake, the body will remove fluid from the cell (ICF), back into the (ECF) outer cell, resulting in reduced performance within the cell.
Water is the prime importance for the regulation of body temperature, over three-quarters of the energy produced during exercise is heat. The body will sweat to prevent overheating, as its vital for optimum performance that you can keep your bodies temperature within safe limits 37-38 degrees centigrade.
Your circulation system (blood) works in conjunction with your sweat production, by transporting a large volume of your blood close to your skin, to help cool down your internal temperature. By removing the blood from your muscles to aid cooling, you will be removing vital nutrients and oxygen which the muscles require from your blood supply, whilst causing your blood pressure to rise.
Dehydration will cause a rapid decline in performance, and greater risk of injury, so its essential to look for, and prevent the signs of dehydration.
- Dry mouth - difficulty in swallowing - feeling thirsty.
- Reduction in urine, normally every 2 - 4 hours.
- Orange or darker urine, should be pale yellow / clear.
- Reduction in performance, difficulty in maintaining exercise level.
- Slurred speech - blurred vision - headache.
- Sweating reduced / stopped.
Daily losses are relatively high, even under normal/moderate temperature and activity. The body needs to replace its entire mass of water every 11 - 13 days.
Water is lost largely through urination as well as by evaporation in breath and sweat. The kidneys normally very carefully regulate the balance of water retained in the body, but excessive losses can result from vomiting, diarrhea, vigorous exercise or high temperatures.
It should be noted that even small losses of water (2-3 % of body weight) can seriously impair performance.
As a rule of thumb 1 oz of water should be consumed per kilogram of body weight. For example a 70kg person should drink 3.5 pints of water or eight 8oz. glasses per day. A good indication of healthy water intake is the color of your urine, - except first thing in the morning, it should be colorless or a pale yellow.
Dehydration Prevention
- Take in fluid (water) throughout the day, try and carry a water bottle with you, feeling thirsty is a poor way to realize that your body needs fluids.
- One gram of glycogen stored within your lean muscle tissue contains approximately 3 grams of water, so keep your glycogen levels well maintained.
- Takes sips of fluid throughout your workout, make it a habit, aim for 250ml every 12 - 20 minutes depending upon your size, activity intensity and external temperature. The harder or hotter it is, the more fluid your body will require, if competing over 60+ minutes, aim to take some energy drink or energy bar / banana etc.
- Prior to exercise maintain optimum hydration levels by drinking 1 - 2 liters of water / sports drink 1 - 4 hours prior to exercise.
- Avoid substances that cause the body to become dehydrated - caffeine - alcohol - certain sports labeled drinks containing high levels of stimulants (Guarana) or high sugar content 10+%.
Sports Drinks
Becoming increasingly popular due to the marketing claims made by athletes from a multitude of sports. Sports drinks come in three main categories.
Hypo tonic-
- 2% concentration or 2 grams of glucose per 100ml of water.
- absorbed quickly into the blood stream.
- contains a small amount of energy.
- suitable for training in hot conditions or events lasting less than 90 minutes.
Isotonic -
- same balance as your blood.
- contains 4 - 7% equal blend of carbohydrates concentration or 4 - 7 grams per 100ml of water.
- ideal for training or events lasting more than 90 minutes.
- absorbed quickly into the blood stream, unless high in salts.
- effective blends will have a varied glucose source, giving energy release at a more controlled level; glucose = immediate energy release, sucrose = mild energy release, and maltodextrin = slow sustained release.
Hyper tonic -
- a higher concentration than blood.
- contains at least 10% of glucose 10 grams per 100ml of water.
- suitable for long endurance events.
- very slow absorption.
- can cause dehydration, stomach cramps or abdominal pain caused by slow release into blood stream.
- aim to try your / events chosen brand prior to your race.