Summer Heat

“In the summertime, when the weather is high”

The days are longer, everything is green, the weather is warm. What could be bad about getting physically active this summer?

While many of us love getting back on the golf course, finding new hiking trails, or getting out on our bikes, there are a few things to consider when being physically active in the summer.

First off; What is happening inside our bodies as we exercise in the heat?
Our bodies are designed to keep our core temperature the same. So when the heat rises a cascade of processes happen to allow us to keep cool. Blood is sent to our capillaries (little tiny blood vessels just below the skin) in an effort to allow it to cool as it comes near the surface, cooling down the system as it circulates back to the heart. We begin to sweat to allow evaporation on the skin to cool ourselves. However, if our ability to cool ourselves is outmatched by the temperature outdoors we can end up with hyperthermia (an excessive body temperature). This can lead to dehydration, loss in blood plasma volume, (which can increase the risk of heart attack), rapid breathing, and reduced blood flow to both the grain & gut.

Physical activity in the heat can also feel harder, as our heart may be beating a little faster in an effort to regulate our temperature. So the added load of exercise can strain your heart & body harder than usual. Blood flow to our brains as well as high level brain activity is reduced causing us to potentially feel more lethargic- so finding that your usual bike ride is harder in July than it was in May is completely normal.

Okay, but what about the heart? Do your thing Pulse- what’s going on there?
Exercise in the heat puts more demand on our cardiovascular system; not only are our working muscles asking for more fuel to move, but our skin and capillaries demand more blood to keep us cool. This increase in demand is met by an increase in output by our heart. How does it meet this demand? The heart will respond expertly by beating more forcefully and more quickly, getting that extra blood flow where it is needed.

As for the blood, we may lose some of our blood plasma volume (don’t worry- we can restore it no problem) as we lose water from sweating. In heat adapted athletes, they have been seen to have a higher plasma volume to offset this loss! However, we also need to be careful of causing an electrolyte imbalance. When we sweat we not only lose water, but electrolytes such as potassium and sodium as well. We drink water to replace the water loss, but the electrolytes do not get replaced, causing an imbalance. This imbalance can impact our heart.

Considerations for getting active in the heat.
No matter the temperature, physical activity is for all four seasons, no matter how short or long they may be where you’re from! Here are some ways to stay moving and keep your cool outdoors this summer.

  • Feels great to hydrate : Make sure to offset water loss through sweat by upping your intake of good ol’ H20. Carry a water bottle, keep a cool pitcher in the fridge, and snack on high-water foods like watermelon and cucumber. Scout’s motto: Be prepared, and with water, bring more than you think you’ll need. While they may be refreshing, alcoholic beverages will actually increase dehydration- virgin mojitos with fresh mint and lime anyone?
  • Early Bird/ Night Owl: Schedule your activities before 10am and around dusk, when the sun has left the middle of the sky and the ground is cooler- sunset bocce anyone?
  • Low & Slow: Knowing what we know now, drop down the intensity slightly when exercising in the heat, listen to your body, and take more breaks if needed.
  • Gimme a Break: Rest- Take more of it, more often, ideally in the shade, or in a space where you can cool down.
  • Listen Closely: Pay attention to the cues your body gives you, taking more breaks, drinking more fluids, and stopping exercise if it gives you signals like fatigue, cramps, pale skin, rapid breathing or excessive thirst.
  • Slip, Slap, Slop & Seek: Slip on a breathable long sleeve shirt, Slap on a wide brimmed hat, Slop on the sunscreen, and seek shade! Beyond the risks of heat exhaustion and heat stroke, the sun’s powerful rays can cause sunburn, skin damage, and skin cancer if we’re not careful.
  • Better Together: Spend time outdoors with family, friends, or your workout buddy- having someone you trust to keep you safe and remind each other to stay hydrated & cool while having fun.

What to do if you get too hot?
Whatever you’re doing, STOP immediately and get yourself to some shade or air conditioning to cool down. Remove excess clothing, pads or equipment, and sip on cool beverages and apply a cool compress. Should you feel confused, dizzy, faint or feel any pain, call emergency services.

Summer is here for a good time, and not a long time- use these tips to sweat safely this summer and share a snap of your outdoor fun on our Facebook page!

While rare and preventable by the above tips, Heat stroke and heat exhaustion are serious business; if you or a loved one experience dizziness, disorientation, nausea, headaches, vomiting, fainting or seizures. Stop activity and seek medical attention or call 9-1-1 immediately. Always consult a trusted medical professional before beginning, changing or stopping any exercise program.

Sources used:
Cheung, S. S., & Ainslie, P. N. (2022). Advanced environmental exercise physiology (2nd ed.). Human Kinetics, Inc.

Zuhl, M. (2019). Information on Exercising in Hot and Cold Environments. Acsm.org. https://www.acsm.org/docs/default-source/files-for-resource-library/exercising-hot-cold-environments.pdf?sfvrsn=1b06c972_4.

Kerry James

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