Heat Wave Guide

A heat wave is a prolonged period of excessive heat and humidity.

In Central Texas, summer heat waves are common, as average high temperatures reach the middle 90s from late June to early September.

2009 was Austin’s hottest summer on record, as an extreme heat wave resulted afternoon temperatures reaching or exceeding 100 degrees on 68 days—the 2nd most in history.

The National Weather Service steps up its procedures to alert the public during these periods of excessive heat and humidity. Excessive heat kills more people in the U.S. than tornadoes, hurricanes, floods, and lightning combined.

In a normal year, approximately 175 Americans die from extreme heat. Young children, elderly people, and those who are sick or overweight are more likely to become victims. Between 1936 and 1975, nearly 20,000 people succumbed to the effects of heat and solar radiation. Because men sweat more than women, men are more susceptible to heat illness because they become more quickly dehydrated.

The elderly, very young, obese and those who work outdoors or have substance abuse issues are most at risk from succumbing to heat. Additionally, people in urban areas are more susceptible as asphalt and cement tend to hold in heat throughout the night.

What to do in a heat wave

Although it may sound like common sense, the best way to avoid the effects of heat is to slow down and avoid strenuous activity. If you must do strenuous activity, do it in the coolest part of the day, which is usually in the morning between 4 a.m. and 7 a.m.

Stay indoors as much as possible. If air conditioning is not available, stay on the lowest floor, out of the sunshine.

Drink plenty of water regularly and often, even if you don’t feel thirsty. Generally, you should follow the "8 x 8 rule" — drink eight 8-ounce glasses of water a day.

If you exercise or engage in any activity that makes you sweat, you need to drink extra water to compensate for the fluid loss. An extra 1.5 to 2.5 cups of water should suffice for short bouts of exercise, but intense exercise lasting more than an hour (for example, running a marathon) requires more fluid intake. How much additional fluid you need depends on how much you sweat during exercise, the duration of your exercise and the type of activity you're engaged in.

During long bouts of intense exercise, it's best to use a sports drink that contains sodium, as this will help replace sodium lost in sweat and reduce the chances of developing hyponatremia, which can be life-threatening. Also, continue to replace fluids after you're finished exercising.
Avoid alcohol and caffeine as they can intensify the heat’s effect on your body. This is especially true about beer because it accelerates dehydration.

Wear lightweight, light-colored clothing. Light colors will reflect away some of the sun’s energy.

Never leave children or pets in the car, even with the windows down. When the outside temperature is only 83 degrees Fahrenheit, and your window is down two inches, the temperature inside your car can reach 109 degrees Fahrenheit in 15 minutes.

Avoid using salt tablets unless directed to do so by a physician.

Warning signs that the heat is getting to you

Heat cramps: Heat cramps are muscular pains and spasms due to heavy exertion. Although heat cramps are the least severe, they are an early signal that the body
is having trouble with the heat.

Heat exhaustion: Heat exhaustion typically occurs when people exercise heavily or work in a hot, humid place where body fluids are lost through heavy sweating. Blood flow to the skin increases, causing blood flow to decrease to the vital organs. This results in a form of mild shock. If not treated, the victim may suffer heat stroke. Symptoms: Cool, moist, pale, or flushed skin; heavy sweating; headache; nausea or vomiting; dizziness; and exhaustion. Body temperature will be near normal.

Heat stroke: Heat stroke is life-threatening. The victim’s temperature control system, which produces sweating to cool the body, stops working. The body temperature can rise so high that brain damage and death may result if the body is not cooled quickly. Symptoms: Hot, red skin; changes in consciousness; rapid, weak pulse; and rapid, shallow breathing. Body temperature can be very high—as high as 105° F. If the person was sweating from heavy work or exercise, skin may be wet; otherwise, it will feel dry.

Sunstroke: Another term for heat stroke.

How to handle heat-related health issues

Heat cramps: Get the person to a cooler place and have him or her rest in a comfortable position. Lightly stretch the affected muscle and replenish fluids. Give a half glass of cool water every 15 minutes. Do not give liquids with alcohol or caffeine in them, as they can make conditions worse.

Heat exhaustion: Get the person out of the heat and into a cooler place. Remove or loosen tight clothing and apply cool, wet cloths, such as towels or sheets. If the person
is conscious, give cool water to drink. Make sure the person