HEAT & CYCLING
Although heat prostration or exhaustion is not life threatening, it often contributes disproportionately to injuries of cyclists, especially to road bikers, than those engaged in other activities. Symptoms of dizziness, fatigue, and cramps can cause a rider to loose concentration, hit obstacles, or make bad decisions, resulting in dangerous or uncontrolled falls, frequently in automobile or pedes-trian traffic.
Most cyclists don't recognize the subtleties in performance brought on by high temperatures and humidity until too late to compensate, making injury only moments away. They fail to take simple preven-tions
For a cyclist suffering from heat exhaustion, his/her discomfort, dizziness and loss of concentration will likely lead to injury. In the early stages, heat exhaustion produces headache, dizziness, and fatigue and can lead to heatstroke, a failure of the the body's temperature to regulate itself. The body does not sweat, and the skin becomes hot, red, and dry. Body temperature may reach as high as 106 degrees, and the pulse rate may increase rapidly to 150 beats per minute (in contrast to heat exhaustion, which slows the pulse rate). These drastic changes in the body can result in convulsions, unconsciousness, and even death.
Heatstroke is an emergency condition, requiring immediate medical care. Body temperature needs to be brought down immediately to avoid the risk of brain damage. Mere first aid efforts are not likely to prevent the more serious consequences of heatstroke. The victim should be placed in the coolest place available--an air-conditioned room, if possible. Sponge the victim with cool water, or wrap him in a cool wet sheet. A heatstroke victim may require several days of hospitalization.
Heatstroke is the escalation of two less serious heat-related conditions. If you don't take steps to treat these lesser conditions quickly, your condition may worsen and become heatstroke:
Heat cramps. Heat cramps are caused by initial exposure to extreme temperatures or physical exertion. Signs and symptoms of heat cramps usually include profuse sweating, fatigue, thirst and muscle cramps. This condition is common in warmer weather or with moderate to heavy physical activity. You can usually treat heat cramps by drinking fluids containing electrolytes (Gatorade or other sports drinks), resting and getting to a cool spot, like a shaded or air-conditioned area.
Heat exhaustion. Heat exhaustion occurs when you don't act on the signs and symptoms of heat cramps and your condition worsens. Signs and symptoms of heat exhaustion include a headache, dizziness or lightheadedness, nausea, skin that feels cool and moist, and dark urine. Often with heat exhaustion, you can treat the condition yourself by following the same measures used to treat heat cramps. If your symptoms persist, seek medical attention immediately.
Heat exhaustion is one of the heat-related syndromes, which range in severity from mild heat cramps to heat exhaustion to potentially life-threatening heatstroke.
Signs and symptoms of heat exhaustion often begin suddenly, sometimes after excessive exercise, heavy perspiration and inadequate fluid intake. Signs and symptoms resemble those of shock and may include:
- Feeling faint or dizzy (from low blood pressure)
- Nausea, headache, and fatigue
- Heavy sweating with cool, moist, pale skin
- Rapid, weak heartbeat
- Low-grade fever
- Heat cramps
- Dark-colored urine
If you suspect heat exhaustion:
- Get the person out of the sun and into a shady or air-conditioned location.
- Lay the person down and elevate the legs and feet slightly.
- Loosen or remove the person's clothing.
- Have the person drink cool water.
- Cool the person by spraying or sponging him or her with cool water and fanning.
- Monitor the person carefully. Heat exhaustion can quickly become heatstroke.
- If fever greater than 102 F (38.9 C), fainting, confu-sion or seizures occur, dial 911 or call for emergency medical assistance.
Proper hydration is the single most important means to prevent heat related illnesses. You can begin to dehydrate before you feel thirsty.
When to drink?
Warning - you can be in early stages of dehydration before you have any sensation of thirst. Drink before you think you need it, a small amount, and often.
How much to drink?
There is no precise answer; it depends on body mass, metabolic rate, how hard you are working, how hot and/or humid it is, how prone to sweating you are, diet, and so on. For cyclists a figure that is often quoted is one litre per hour.
Ways to tell if you are not drinking enough include:
- A raging thirst after a ride is a sure sign of under-hydration. If the ride is only an hour or so then this is unlikely to be dangerous, but it’s still better to forestall it.
- Waking up with a ‘hangover’ the next morning is also a sign that you haven't taken on enough liquid during the ride.
- The ‘pee test’. If you feel the need to urinate at about the same interval when riding as you do when not exercising, you’re probably adequately hydrated. If the intervals get longer and longer, or the volume is reduced, you should up your fluid intake. And if what’s coming out is significantly darker in colour than normal, this is a real warning sign.
- Headache, dizziness, 'hungover' feeling. All are likely symptoms of dehydration.
Links on Proper Hydration
