diabetes, hydration and extreme heat: what you should know
4 minute read
dehydration can make blood sugars rise to dangerous levels, and since the symptoms of heat exhaustion are similar, it can be hard to tell the difference.
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living with diabetes is challenging, but it can become even more so when the summer heat shows up.
“in people with diabetes, exposure to prolonged heat can cause glycemic excursions towards either extreme,” said dr. akshay jain, a clinical endocrinologist and medical director for research at unity healthcare, in an email to healthing.
for example, exposure to extreme heat can cause dehydration, which drives high blood sugar. dehydration itself causes blood sugar levels to rise, which in turn increases urine output, making dehydration worse. this becomes a “vicious cycle” of hyperglycemia and dehydration, both of which can be detrimental to someone living with diabetes.
on the other hand, heat stress on the body, especially during times of high activity, can cause the body to absorb insulin faster, which can drive blood sugar lower. so, both high and low blood sugar levels can be driven by heat, which makes staying hydrated and having a well-regulated temperature vital over the summer months for someone living with diabetes.
heat, dehydration and diabetes
dehydration affects the body’s ability to regulate temperature in ways that can cause heat exhaustion or heat stress. in people with diabetes, the body’s ability to regulate temperature during times of extreme heat is already compromised because many people have nerve and blood vessel damage that interferes with sweat production and circulation, both of which are required for adequate regulation.
the part of the brain responsible for temperature regulation, the hypothalamus, sends signals through nerves to blood vessels to tell them to either expand or constrict so that it can release or conserve heat, respectively. in the case of extreme heat, blood vessels need to dilate properly to help cool overall temperature.
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in diabetes, when blood vessels dilate in response to heat, it can be an issue because of how that affects insulin.
“heat dilates blood vessels and speeds up absorption of rapid, soluble insulins, which can increase the risk of low blood sugar,” said dr. jain.
dehydration can also cause a level of impairment that makes it hard to tell if you aren’t feeling well, and if you feel off, the cause behind it, whether it be from the heat directly or because of what it’s doing to blood sugar levels. it can be especially harmful for people with diabetes who have comorbidities.
“dehydration can blur thinking and make it hard to tell whether you’re feeling off from heat or from blood sugar changes,” said dr. jain. “poor hydration also increases the risks of severe complications like hyperglycemic emergencies and can worsen kidney strain, especially in those with existing kidney disease.”
managing hydration to take care of blood sugar
staying hydrated during the summer may be more challenging because it’s easy to lose fluids through sweat and urine output, especially if blood sugar levels are higher than they should be.
but staying on top of hydration is the best way to ensure that you’re also staying on top of your diabetes care. dr. jain recommends drinking a minimum of two litres of water per day, three if you’re going to be out doing activities during the daytime.
he notes that you should drink “water regularly, not just when thirsty.”
you can also pay attention to the colour of your urine, which gives you a good idea of how hydrated you are.
“pale yellow is better than dark,” said dr. jain, stating that this should be done daily.
during times of extreme heat, it’s also best if you monitor your blood sugar levels more often than you would in other temperatures because of how they can rise and fall dangerously in the presence of heat stress and dehydration. older adults may benefit from weight-based checks as well, noticing that if there’s an unexpected drop in weight on hot days, it may indicate that they are not hydrated enough.
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if you want to get out and enjoy the heat without worrying about your blood sugar, there are also a few tips dr. jain swears by.
“drink water consistently and carry it when you go out. limit alcohol and sugar drinks; avoid caffeine-heavy beverages as primary hydration,” he said. “check blood sugars before, during and after outdoor activity; adjust insulin doses only in accordance with your care plan.”
it’s also important to remember that finding some shade and taking air-conditioned breaks away from the heat every so often are great ways to keep the heat from causing dehydration and imbalanced blood sugar levels.
if you find yourself concerned about the heat and would rather avoid it, you can always check the heat index to see both the temperature and humidity levels so you can plan outdoor activities on days when it’s a bit more comfortable.
and when you do start to experience symptoms, remember that they can be challenging to discern between blood sugar and heat exhaustion, so it’s always best to test when you’re feeling ill.
“heat increases the risk of both severe high and low sugars, and symptoms can overlap with heat exhaustion. don’t ignore confusion, dizziness, or extreme fatigue. test your sugar and seek help if needed,” he said.
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