What is heat exhaustion?
Heat exhaustion is a mild form of heat-related illness and associated with a core body temperature of 37 - 40°C (98.6-104°F). Heat exhaustion causes a person to become unable to continue activity because of environmental conditions, like hot weather, or over exercising. It is caused when body’s thermoregulatory responses (sweating, dilation of veins, etc.) are inadequate to cool the body down. .
Symptoms of heat exhaustion:
• Heavy sweating
• Feeling weak and/or confused
• Dizziness
• Nausea
• Headache
• Fast heartbeat
• Skin appears pale or ashen
• Dark-coloured urine, which indicates dehydration
What should I do if I think I have heat exhaustion?
If you think you have heat exhaustion, get out of the heat quickly. Rest in a building that has air-conditioning, or if you can't get inside, find a cool, shady place. Drink plenty of water or other fluids, but do NOT drink alcohol or caffeinated drinks (such as pop). These can make heat exhaustion worse. Take a cool shower or bath, or apply cool water to your skin. If you can, lay on your back, preferably with your legs elevated. Take off any tight or unnecessary clothing.
If you do not feel better within 30 minutes, you should contact your doctor. If heat exhaustion is not treated, it can progress to heatstroke.
What is heatstroke?
Heatstroke (also known as sunstroke) is when the internal temperature of the body reaches 40°C (104°F). It can happen when your body gets too hot during strenuous exercise or when exposed to very hot temperatures, or it can happen after heat exhaustion isn't properly treated. Heatstroke is much more serious than heat exhaustion. Heatstroke can cause damage to your organs and brain. In extreme cases, it can kill you.
How can I prevent heat illness?
When the temperature is high, stay indoors and/or in air-conditioned areas, when possible. If you must go outside, take the following precautions:
• Wear lightweight, light-coloured, loose-fitting clothing;
• Protect yourself from the sun by wearing a hat or using an umbrella;
• Use sunscreen with a sun protection factor (SPF) of 15 or more;
• Drink plenty of water before starting an outdoor activity. Drink extra water all day. Keep in mind that heat-related illnesses are not only caused by high temperatures and a loss of fluids, but also a lack of salt in the body. Some sports drinks can help replenish the salt in your body lost through sweating;
• Drink fewer beverages that contain caffeine (such as tea, coffee and pop) or alcohol;
• Schedule vigorous outdoor activities for cooler times of the day -- before 10:00 a.m. and after 6:00 p.m.;
• During an outdoor activity, take frequent breaks. Drink water or other fluids every 15 to 20 minutes, even if you don't feel thirsty. A good indicator of hydration is urine. If you have clear, pale urine, you are probably drinking enough fluids. Dark-coloured urine is an indication that you're dehydrated;
• If you have a chronic medical problem, ask your doctor about how to deal with the heat, about drinking extra fluids and about your medicines.
Risk Factors for Heat-Related Illness:
• Age older than 65 years or younger than 15 years
• Cognitive impairment
• Heart and lung diseases
• Limited access to air-conditioning
• Mental illness
• Obesity
• Physical disabilities/impaired mobility
• Poor fitness level
• Sickle cell trait
• Strenuous outdoor activity during hottest daytime hours
• Living on higher floors of an apartment building
Sources
Ainsworth, S. (2009). Staying healthy if the heat rises. Practice Nurse, 38(3), 43-44.
Becker, J., & Stewart, L. (2011). Heat-related illness. American Family Physician. 83(11), 1325-1330.
Glazer, J.L. (2005). Management of Heatstroke and Heat Exhaustion. American Family Physician. 1(11), 2133-2134.
