Dr. Meaghan Datema, ND

How to survive summer workouts

FINALLY! Summer is on its way. In Southern Ontario we have had a below average spring, temperature wise. I went for a walk in the middle of May still wearing my winter coat because we were trapped in a polar vortex. But this past week the weather has shifted and we said goodbye to winter temperatures and hello to summer heat.

One of the challenges that comes with summer temperatures is how to stay cool. People living without AC know this. Try getting a good night sleep while it feels like you are in the middle of the Amazon jungle. This applies to workouts as well. Heat adds an extra intensity to your workouts that is not there in the more moderate or cooler seasons. When the temperatures start to soar there are a few things that you need to keep in mind.

Why heat adds intensity to workouts

When you work out in the heat even simple workouts appear harder. Why? The heat increases your body’s internal temperature along with the heat you generate while exercising. All of a sudden your body has to work much harder to cool your temperature. It does this by 2 ways. 

First through increasing blood flow to the skin. The air temperature is generally cooler than your body temperature, therefore, sending blood to your skin will cool your blood down closer to room temperatures. The slightly cooler blood, overtime, will help bring the core body temperature back down. This is why your skin is typically red after a workout. It is your body’s built in AC system. This system is great, however, there is one “flaw”. If more of your blood is going to your skin to cool you down, then there is less blood (and oxygen) able to go to your muscles. This will decrease energy production and increase lactic acid production in your muscles making the workout seem harder. Again, this is intentional. Your body is trying to cool you down, and one of the easiest ways to do that is to stop producing heat i.e. stop exercising. 

The second way that your body attempts to cool your body temperature down is through sweating. The moisture of sweat on your skin cools your body down, along with the evaporation of sweat. When the humidity is high, the sweat doesn’t evaporate as quickly. This will result in a higher body temperature.

Heat related illnesses

Heat Cramps: also called exercise-associated muscle cramps are muscle contractions that occur with exercise. The muscle will be painful, hard, or spasming. This is due to the loss of electrolytes and water due to prolonged sweating.

Fainting: Heat can cause a feeling of lightheadedness or fainting caused by prolonged exposure to high temperatures. Often caused by standing for a prolonged period of standing, or standing too quickly. 

Heat exhaustion: heat exhaustion occurs after spending a prolonged period of time in the heat. Note that the length of time it takes to develop heat exhaustion varies person to person, and can vary for an individual based on activity in the heat. When spending a prolonged period of time in the heat be on the lookout for: heavy sweating, cold and clammy skin, increased heart rate, nausea, muscle cramps, fatigue, dizziness, headaches, and fainting. 

Heatstroke: Heatstroke is a life threatening condition that occurs when your body temperature is greater than 40C. Signs of heatstroke include: red hot skin, rapid pulse, fainting, headache, dizziness, confusion, lack of sweating, and fainting.


When working out or playing sports in the heat it is very easy to become dehydrated due to the lack of fluid consumption and the increased amount of sweating. Dehydration has 3 main stages. 

  • Mild dehydration: dry lips and mouth, thirst, less urine volume.
  • Moderate dehydration: thirst, very dry mouth, sunken eyes, tenting of skin when pinched with no bounce back, and low or no urination.
  • Severe dehydration: Rapid and weak pulse, cold hands and feet, rapid breathing, blue lips, lethargic, comatose, seizures, and requires immediate hospitalization

Dehydration while working out or playing sports is important to monitor because it can have a significant impact on your ability to workout. A drop of 1% of your body weight due to dehydration will result in decreased performance, decreased strength, and decreased mental clarity.

How to workout safely in the heat

How heat and humidity changes heat stroke risk

When working out in the heat, keep these principles in mind.


When exercising in elevated temperatures (>27C) your body needs approximately 600-1000mL of fluid per hour of activity. If you want to get very specific with the amount of fluid you should be drinking you can calculate your sweat rate. You can calculate sweat rate by weighing yourself before and after a 1 hour exercise session. Each kilogram of weight lost is roughly equivalent to 1L of fluid.

Replace electrolytes lost

Sweat loss will also result in losses of sodium, chloride, and to a lesser extent potassium. When electrolyte levels drop you will experience more muscle cramping. When looking for an electrolyte replace look for one that provides 200-550mg of sodium per L.

Stick to the cooler times of the day

This kind of goes without saying. Working out earlier in the morning or later in the evening when the temperatures are lower will decrease sweat loss and decrease the risk for dehydration. During the warmer months my favourite time to workout is 8pm.

Let someone know that you are working out

If you are working out alone you should always let someone know where you are going and how long you will be gone for. This is even more important in the warmer temperatures that way there is always someone who knows where you are in case your workout doesn’t go as planned.

Don't be afraid to cut the workout short

If you start out wanting to work out for 1 hour or to go for a 10k run, but part way through it starts getting harder than normal, don’t be afraid to cut it short. That is your body’s way of telling you that it is too hot. There is always tomorrow

Don't forget the sunscreen

If you are going to be outside, PLEASE don’t forget the sunscreen. If you don’t want to put on the sunscreen, opt for UV resistant clothing and a hat. Protect your skin.

I am just as excited as you are to finally be enjoying some warmer weather. Just keep these principles in mind as you are putting on your running shoes! And don’t forget the water bottle!

If you are wondering where to start with a workout recovery plan or with how to eat to better fuel your workouts click the button below. I have put together a special initial consultation package for all athletes that will go over how you are exercising, what you are doing to fuel your body, and what supplements to take. It will also include your first acupuncture or cupping session! See you soon!

Yours in health,

grimsby naturopath

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