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Exercise, Physical Activity & Hot Weather
Yeah!!! It was a bit slow in coming but the hot weather has finally arrived. It is a great time to get out of your homes and enjoy the beautiful outdoors. As Canadians we are known to be outdoor people and we love being out in nature. Some favorite and most popular activities are: walking, hiking, biking, swimming, SUP’ing, kayaking, gardening, fishing, camping … list goes on and on!
As health care professionals we encourage people to get outside and reap all its health benefits. Research shows that exercising and/or being active outdoors provides a positive impact on our mind, body and soul. Now that I have pumped up everybody to get outside and play we must be mindful about the heat! I don’t mean to be a party pooper … but we must be careful that our bodies don’t over heat because this can have serious medical and health consequences. We must take precautions … just like a car our bodies can over heat and breakdown!
Here is a short and sweet physiology lesson on how your body regulates its core temperature.
Our bodies are set up to keep the internal temperature between 36.5 and 37.7 degrees Celsius. It’s happiest between these temperatures . With exercise our body temperature naturally goes up above 37.7 degrees so in order to cool itself our bodies start to sweat and the body is then cooled by the evaporation of sweat from the surface of the skin. This action transfers the heat from your blood to the air. This creates a cooling affect…that’s great! The problem occurs if the outside air is very hot and humid meaning the air is highly saturated with water then your sweat cannot evaporate into the air and therefore your body cannot cool itself...oh oh!
As well, as your body works hard to cool itself you sweat heavily and lose a lot of fluid. This can cause your core temperature to increase even higher and depending on how high your core temperature climbs it can cause heat cramps or progress to heat exhaustion or the last and worst progression is heat stroke which is a medical emergency. Bottom line is we want to avoid overheating!!!
These are definitions and symptoms of Dehydration: Heat exhaustion and Heat stroke.
Dehydration occurs when the body does not have enough fluid. Dehydration can occur in phases, with each phase becoming more serious.
There are 3 stages of dehydration
Stage 1: Heat Cramps
Heat cramps may happen when you first start to become dehydrated.
Signs of heat cramps:
Cramps in the calves and/or abdomen due to a loss of sodium from muscle cells.
Action: Move to shade, reduce activity and re-hydrate.
Stage 2: Heat Exhaustion
Heat exhaustion can occur when you are exposed to high temperatures and you do not replace fluids.
Signs of heat exhaustion:
Fatigue and weakness leading to dizziness.
Shortness of breath.
Nausea.
Vomiting.
Unsteadiness.
Action: Cool person down immediately example: move person to shaded area/fan/air conditioning, have person lie down, hydrate with water, monitor person carefully.
Stage 3: Heat Stroke
Heat stroke is a medical emergency. Heat stroke happens when the body’s temperature has risen to 39°C or higher.
Signs of heat stroke:
Be unbalanced or unsteady on your feet.
Feel confused or disoriented.
Have bizarre behavior.
Your body can no longer sweat!
Action: Person can fall into a coma therefore needs medical attention immediately (911). Person needs to be cooled down immediately ie; move person to shaded area/fan/air conditioning, have person lie down, elevate legs, cold water sponging/bath, and monitor person carefully until EMS arrives.
Here are a few tips to prevent overheating on hot humid day’s altogether
Proper hydration; make sure you are drinking plenty of water before, during and after physical activities.
Wear light colored clothing.
Wear a light hat to avoid direct sun.
Avoid drinking alcohol.
Get your exercise completed in the morning before 11 am.
Wear clothing poly-synthetic shirts/tops which allows for sweat to be wicked away from your body. Remember: Avoid 100% cotton fabrics when exercising as it holds sweat to your body and acts to keep heat in.
Take cool showers to cool body or get in a pool/lake.
Take breaks from direct sunlight seek shelter in shaded area.
Heat Safety Index
The Heat Safety Index will help you make a decision about whether or not outdoor exercise is safe.
- Check your local weather conditions to find the current temperature and humidity reading.
- Look for the absolute temperature along the bottom of the graph. For example you look up the temperature on your computer or app and it indicates 32 degrees Celsius and also indicates it “feels like” 37 degrees use the 32 degrees when checking the on the graph not the “feels like’ temperature.
- Look for the percentage of humidity along the left hand border of the graph. Remember humidity typically climbs during the day. For example it might be 55% in early morning and 85% by noon.
- Find the place on the graph where these two points come together. The zone that you are in can tell you whether it is safe to exercise outdoors.
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