Some like it Hot, Hot, Hot!
Finally Summer is fully upon us!
The sun is smiling down its shine, giving us plenty of Vitamin D.
But also giving us a heat wave, including some super humid, muggy, soupy days. And you do not want to stop exercise completely on these days, right? But you do not necessarily want to be outside on these days, either. So….how do you stay motivated and keep from getting heat exhaustion?
How heat affects your body:
Under normal conditions, your skin, blood vessels and perspiration level adjust to levels of heat. But these natural cooling systems may fail if you are exposed to high temperatures and humidity for too long, sweat heavily, and do not drink enough fluids. Exercising in hot weather puts extra stress on your body. Both the exercise itself and the air temperature and humidity can increase your core body temperature. To help cool itself, your body sends more blood to circulate through your skin. This leaves less blood for your muscles, which in turn increases your heart rate. If the humidity also is high, your body faces added stress because sweat doesn’t readily evaporate from your skin. That pushes your body temperature even higher and puts you at risk for potentially serious illness.
Exercising, running, and even walking in the heat and humidity takes a lot more effort than in cool crisp weather. Your VO2 max (or your ability to use oxygen to create energy) diminishes. You will dehydrate much quicker, which not only will further diminish your VO2 max, but also can create electrolyte imbalances and heat exhaustion. Heat exhaustion can lead to Heat Stroke, where your body temperature rises to dangerous temperatures, and must be treated promptly.
Sweating is the body’s way of trying to control its temperature. Under most circumstances it works very well. In high heat settings it can sometimes work to your disadvantage if you are not prepared. In very dry, or very humid conditions sweating can lead to severe dehydration.
During an extended period of exercise you can lose a few liters of fluid. In high heat, but low humidity conditions, the sweat is evaporated rapidly. You may feel like you’re not losing a lot of fluid, but you are. In high humidity environments the sweat does not evaporate nearly as rapidly, therefore your body’s response is to sweat even more as it attempts to cool you down. The volume of fluid in your blood vessels might only be 3-5 liters. If you sweat or exhale three liters of fluid during exercise and do not replenish it your body will draw fluid away from your muscles, and other organs to maintain the fluid level in your blood vessels. This is why dehydration can affect all your systems in your body…and lead to shutdown of several systems in your body.
How to spot the warning signs:
During hot-weather exercise, be aware of signs and symptoms of heat-related illness in yourself and others. Do not ignore these symptoms, for the condition can worsen, resulting in a medical emergency. Signs and symptoms may include:
- Muscle cramps
- Nausea or vomiting
- Weakness
- Fatigue
- Headache
- Excessive sweating
- Dizziness or lightheadedness
- Confusion
- Irritability
- Low blood pressure
- Increased heart rate
- Visual problems
Definitions of Heat-related illnesses:
- Heat cramps.Heat cramps, sometimes called exercise-associated muscle cramps, are painful muscle contractions that can occur with exercise. Affected muscles may feel firm to the touch. You may feel muscle pain or spasms. Your body temperature may be normal.
- Heat syncope and exercise-associated collapse.Heat syncope is a feeling of fainting or lightheadedness caused by high temperatures, often occurring after standing for a long period of time, or standing quickly after sitting for a long period of time. Exercise-associated collapse is feeling lightheaded or fainting immediately after exercising, and it can occur especially if you immediately stop running and stand after a race or a long run.
- Heat exhaustion.With heat exhaustion, your body temperature rises as high as 104 F (40 C), and you may experience nausea, vomiting, weakness, headache, fainting, sweating and cold, clammy skin. If left untreated, heat exhaustion can lead to heatstroke.
- Heatstroke is a life-threatening emergency condition that occurs when your body temperature is greater than 104 F (40 C). Your skin may be dry from lack of sweat, or it may be moist.
How to avoid heat-related illnesses:
When you exercise outside in hot weather, keep these precautions in mind:
- Watch the temperature and avoid midday sun.Pay attention to weather forecasts and heat alerts. Know what the temperature is expected to be for the duration of your planned outdoor activity. Exercise in the morning or evening, when it’s likely to be cooler outdoors. If possible, exercise indoors with a fan or air-conditioning, or outdoors in shady areas, or do a water workout in a pool.
- Get acclimated.If you are used to exercising indoors or in cooler weather, take it easy at first when you exercise in the heat. It can take up to two weeks to adapt to the heat. As your body adapts over time, gradually increase the length and intensity of your workouts.
- Know your fitness level.If you’re unfit or new to exercise, be extra cautious when working out in the heat. Your body may have a lower tolerance to the heat. Reduce your exercise intensity and take frequent breaks.
- Drink plenty of fluids.Dehydration is a key factor in heat illness. Help your body sweat and cool down by staying well-hydrated with water before, during, and after exercise. Do not wait until you are thirsty to drink fluids. If you plan to exercise intensely, consider a low-sugar sports drink instead of water. Sports drinks can replace the sodium, chloride, and potassium that you lose through sweating. Avoid alcoholic drinks because they can actually promote fluid loss.
- Dress appropriately.Lightweight, loose-fitting clothing helps sweat evaporate and keeps you cooler. Avoid dark colors, which can absorb heat. If possible, wear a light-colored, wide-brimmed hat as well as sunglasses to protect your face and eyes.
- Wear sunscreen.A sunburn decreases your body’s ability to cool itself and increases the risk of skin cancer.
- Have a back-up plan.If you’re concerned about the heat or humidity, stay indoors. Work out at the gym, walk laps inside the mall or climb stairs inside an air-conditioned building.
- Understand your medical risks.Certain medical conditions or medications can increase your risk of a heat-related illness. If you plan to exercise in the heat, talk to your doctor about precautions. Consider using a heart rate monitor, if appropriate to your condition.
While well-conditioned athletes will rarely go on to develop heat stroke, there are folks who are most at risk: young children, the elderly, poorly conditioned athletes and those with chronic heart disease or other illnesses. Those of you in the high risk group should not be exercising in the heat.
What to do: If you develop signs of heat exhaustion, stop exercising immediately and get out of the heat. If possible, have someone stay with you who can help monitor your condition and assist with any necessary care. In cases of heatstroke, due to confusion and mental status changes, you likely will not be able to treat yourself and will 
require emergency medical care.
The most effective way of rapid cooling is immersion of your body in a cold- or ice-water tub.
In cases of heat exhaustion, remove extra clothing or sports equipment. If possible, fan your body or wet down your body with cool water. You may place cool, wet towels or ice packs on your neck, forehead and under your arms, spray yourself with water from a hose or shower, or sit in a tub filled with cold water. Drink fluids such as water or a sports drink. If you do not feel better within about 20 minutes, seek emergency medical care.