The environment is changing more rapidly than scientists anticipated. With it, we are experiencing an increased frequency of extreme weather events.
Health problems that arise during extreme heat
Summer temperatures are predicted to increase in the coming decades, with average day-time temperatures reaching 30 degrees Celsius and higher. Intense heat waves and sustained high temperatures are expected to become more commonplace. Unfortunately this is associated with a higher incidence of heat-related illness, adverse health outcomes and even death. When outdoor temperatures are high, most people limit their time spent outdoors, but these conditions become problematic in situations where this is not possible (for example, an outdoor working environment). Even currently recommended heat exposure guidelines will not be enough to protect workers.
Indoor temperatures can also reach dangerous levels during the summer, and this becomes particularly relevant for locations populated with vulnerable individuals (for example, schools, hospitals, long-term care facilities and homes without air-conditioning systems). Even small elevations in outdoor temperatures translate to rising indoor temperatures that are associated with negative health outcomes such as reduced functional ability and sleep quality, as well as mental fatigue. Despite general recommendations for indoor temperature limits (for example, Toronto Public Health and World Health Organization), the evidence for which conditions are associated with the highest risk is severely lacking.
Extreme heat and issues for people with chronic diseases
Older adults and people with chronic conditions like diabetes and hypertension have a harder time cooling their bodies, both at rest and during activity. Their natural heat‑control systems—such as brain, blood vessels, sweat glands and cells—don’t work as well. To cool down, the heart and blood vessels must work harder to send more blood to the skin, adding extra strain. Combined with a reduced ability to sense and respond to heat stress, this raises their risk of hospitalization and health complications in hot weather.
How does diabetes affect the cooling process?
Some people with diabetes, especially if they’ve had it for many years or have complications, can develop:
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Nerve damage (autonomic neuropathy): This can reduce sweating, so the body can’t cool down as well.
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Damage to blood vessels: This can limit how well the blood vessels near your skin open up to release heat.
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Less thirst sensation: You may not feel thirsty even when you need more fluids.
All of these can make it harder to stay cool in the heat.
Research initiatives regarding extreme heat and its effects on the body
A study from the University of Ottawa’s Human and Environmental Physiology Research Unit (HEPRU) has confirmed that the limits for human thermoregulation—our ability to maintain a stable body temperature in extreme heat—are lower than previously thought.
What can you do to stay safe during extreme heat?
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Drink water regularly, even if you’re not thirsty.
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Stay indoors in air-conditioned places during the hottest hours (usually mid-afternoon).
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Wear lightweight, light-coloured clothes.
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Check your blood sugar more often, as heat can change how your body uses insulin.
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Store your insulin and supplies somewhere cool (not in direct sun or a hot car).
