This condition is caused by the loss of both water and salt, with deficits of other ions as well such as potassium, and also with the frequent disruption of the acid-base equilibrium of the body. There are three major groups of dehydration: 1) Loss of water 2) Loss of salt 3) Isotonic losses of salt and water In loss of water, failure to drink is the most common cause. Also, ingesting abnormally large amounts of protein can cause excessive excretion of water by the kidneys and lead to a water deficit. In this case urine output is high, and this aggravates the water loss. Diabetes insipidus may also be responsible for large deficits of water, and these patients must be extra cautious concerning dehydration when exercising. The most common cause of water loss dehydration is SWEATING, and this is of concern to the mountainbiker, especially in hot and humid weather. Your thirst will tell you if this condition is developing. In loss of salt, the body does not get enough sodium, chloride, potassium, magnesium and other electrolytes to replace what is lost or excreted. There can also be a water deficit, but the risks here are associated with the loss of electrolytes, the acid-base balance, and the associated muscle weakness or cramping. Water loss dehydration, if not remedied, can progress to the loss of these necessary salts. In loss of both water and salt, the dehydration can be classified as severe and life threatening if not reversed in time. Don't ever let it get to this point! A few simple steps can eliminate this concern. Replenish both water and electrolytes frequently in hot weather or where dehydration is a problem (i.e. vomiting or diarrhea). If temperature or humidity is high, you will lose a lot of water and salts by sweating and respiration. This can be increased by strenous exercise and overheating. Fever, hyperthyroidism, and increased respiration will also aggravate water loss from your body. Here are some simple steps to follow to prevent dehydration: Drink plenty of fluids before riding on hot and humid days at least an hour before you ride. These should contain valuable electrolytes as well as water. Drinks with sodium, potassium, chloride, and magnesium are good. Also insure an adequate intake of plain water. You must force these fluids even if you are not thirsty. Several liters of fluid can be consumed at this stage. This may be especially important if you consumed alcoholic beverages the night before. Avoid drinks with caffeine or alcohol. Replenish your supply while on the trail every 20 minutes or so. Try to avoid direct sunlight or overheating yourself when you feel dizzy or exhausted. Cooling off in a stream or lake can stop the water and electrolyte loss from sweating. Also, it is important to take frquent rest stops. Make sure you carry a more than adequate supply of water before you start your summer rides. Keep in mind that your body will dehydrate faster at higher altitudes, mainly because of increased loss of moisture thru a higher respiration rate. Plan accordingly... Use an hydration system like a Camelback in addition to water bottles. Place it in the refrigerator the night before you ride, and add some ice cubes right before you leave to ride if it is hot outside. Stock up on electrolytes by drinking fluids high in these, such as cytomax pre-formance, powerade or gatorade, etc... several hours before you ride. Carry a water filtration device on rides when you can't carry enough water to drink if you know water sources are available. Plan a hot summer ride to include a swim, or replenishment from a known safe water source while on the trail. Some mountains have naural springs which can have better quality water than you normally drink. Use these to full advantage. Hydrate fully on return from your ride. This is usually instinctive, but we thought we would remind you of it's importance. Especially true if you are doing a repeat ride the next day. Now is your chance to guzzle to the max. Remember the PRE-hydrate & RE-hydrate rules... drink a lot of fluids starting about 1-2 hours before your ride & drink copiously after you're back |
