Does Warm Weather Affect Blood Sugar Levels? What You Need to Know

Key Takeaways

• Hot weather can significantly alter blood sugar levels, increasing the risk of hyperglycemia and hypoglycemia.
• People with diabetes can stay safe in warm weather by staying hydrated, protecting their diabetes supplies from heat damage, and monitoring their blood sugar frequently.

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As the temperatures climb, managing blood sugar levels becomes even more important, especially for people who live with diabetes. Whether you have type 1 or type 2 diabetes, high temperatures and hot weather can create challenges that may affect your blood glucose levels, your medication, and even your ability to stay safe during outdoor activities.

Understanding how heat affects blood sugar can help you make smarter decisions and stay ahead of potential problems. Here’s what you need to know about diabetes care as the weather heats up.

How Heat Influences Blood Sugar Levels

When exposed to high heat, your body has natural checks and balances to cool itself down. These involve physiological changes like increased blood flow to the skin and stimulation of the sweat glands. While these responses are essential for keeping you cool, they can indirectly affect your blood glucose levels in a number of ways.

For starters, heat can cause dehydration, which reduces blood volume and may concentrate glucose in the bloodstream. This can potentially cause high blood sugar levels and other complications. Research confirms that inadequate hydration is linked to poor glucose regulation and an increased risk of hyperglycemia in people with diabetes.¹

On the other hand, warm weather can also increase insulin absorption rates. A study found that insulin disappeared from the injection site faster at 95°F compared to 68°F, potentially leading to hypoglycemia.²

Fluctuations in blood sugar are more likely to occur when you're physically active in the heat. It’s been shown that whole body heat stress (induced by exercising in the heat) not only raises glucose levels but also decreases glucose uptake, which can exacerbate blood sugar swings.³

4 Risks Associated with Hot Weather for People with Diabetes

While anyone can be affected by extreme temperatures, people with diabetes face a higher risk of complications from heat exposure. Here are some key concerns to watch for.

1. Heat Exhaustion and Heat Stroke

High heat and humidity increase the risk of heat exhaustion and heat stroke, which can be serious medical emergencies. Signs of heat exhaustion include dizziness, fatigue, nausea, and excessive sweating. If left untreated, heat stroke may cause confusion, rapid pulse, and even unconsciousness. 

2. Dehydration

Dehydration not only impacts how you feel, but also how your blood sugar behaves. It reduces blood volume, concentrates blood glucose, and increases the risk of hyperglycemia. Studies show a direct link between hydration status and glycemic control.¹

3. Damage to Diabetes Supplies

Heat can damage medical equipment like blood glucose meters, test strips, insulin pumps, and continuous glucose monitors. Additionally, insulin can degrade in temperatures above 86°F, reducing its potency. For these reasons, it’s important to never leave diabetes supplies in a hot car or in direct sunlight.

4. Worsening of Chronic Conditions

High temperatures have been associated with increased emergency hospital visits for people with diabetes. In one study, researchers found increased diabetes-related complications during extreme heat events.⁴

6 Practical Strategies for Managing Blood Sugar in Warm Weather

Fortunately, there are steps you can take to protect your health and prevent heat-related blood sugar fluctuations. Below are our top tips on keeping your blood sugar in check as the temps go up.

1. Stay Hydrated

Drink plenty of water and don’t wait until you’re thirsty. Dehydration makes it harder to stabilize blood sugar and increases the risk of other heat-related complications.

2. Time Outdoor Activities Wisely

Plan physical activity for early morning or late evening when the temperature is cooler. It’s also a good idea to avoid peak sun hours and take breaks in air-conditioned or shaded areas.

3. Monitor Blood Sugar Frequently

Use a CGM (like the one Signos provides) or test strips more often than usual to watch for changes in blood sugar. Heat and physical activity can lower levels quickly and unexpectedly.

4. Store Supplies Properly

Keep items like insulin, test strips, and diabetes equipment out of direct sunlight. Use a cooler or insulated bag when you're on the go.

5. Protect Your Skin

Sunburn can increase stress hormones and elevate blood sugar.  Remember to apply sunscreen liberally and repeat every two hours when spending an extended time outdoors.

6. Dress Smart

Choose breathable, moisture-wicking fabrics to stay cool and prevent overheating. A hat and sunglasses can also reduce your sun exposure. 

When to Seek Medical Attention

Hot weather can quickly lead to complications if you have diabetes. Contact a medical provider immediately if you notice any of the following symptoms:

• Persistent high or low blood sugar readings despite adjustments
• Dizziness, confusion, or rapid heartbeat
• Signs of dehydration that don’t improve with fluids
• Concerns that your insulin or diabetes equipment may have been compromised by heat

The Bottom Line

Warm weather and high temperatures can significantly affect blood sugar levels and can make it more challenging to manage your diabetes. Dehydration, heat stroke, and degradation of medical supplies are just a few of the risks people with diabetes face during the summer heat.

By staying hydrated, protecting your medication and equipment, and closely monitoring your glucose levels, you can enjoy the season while staying safe. Don’t hesitate to talk to your endocrinologist or healthcare provider about adjusting your diabetes care plan for the heat.

Learn More With Signos’ Expert Advice

Signos incorporates cutting-edge research and the proven power of continuous glucose monitoring to help you lose weight and reach your health goals. Interested in learning more about nutrition and healthy eating habits? Check out more articles on our blog.