Summer Tips for Insulin Pump and CGM Users
Summer brings longer days and more opportunities to enjoy the outdoors. However, for individuals who wear an insulin pump and continuous glucose monitor (CGM) daily, the heat and humidity bring a few additional considerations. For example, can you swim with your devices? Does sweat affect the adhesive? How should you store insulin when temperatures rise? This article walks through the key questions and practical tips to help you enjoy the season safely and confidently.
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Any changes to insulin dosing or device usage should be made under the guidance of your healthcare provider. For specific product usage guidelines, always refer to the instructions provided with your device.
How Summer Heat Affects Blood Sugar and Insulin Absorption
The effect of summer heat on blood sugar is more complex than most people realize. In hot weather, the blood vessels near the skin dilate naturally, speeding up local circulation. This can cause insulin delivered through your pump to be absorbed faster than usual, leading to a quicker drop in glucose levels and a higher risk of hypoglycaemia. This is especially common during outdoor activities. Many users have noticed that even slight exercise in the heat can lower their glucose levels more than the same activity in cooler weather.
If you wear a CGM, this diabetes patch has an advantage: you can see how your body responds to the heat immediately. Checking your sensor readings before, during, and after summer outings can help you spot downward trends early. You don't have to check constantly. Instead, the CGM patch provides the information you need to decide whether to have a snack or adjust your activity level.
Dehydration and CGM Accuracy: Why Readings May Drift, and How to Stay Hydrated
Heavy sweating without enough fluid replacement can lead to dehydration when you're active outdoors on a hot day. For example, take a long hike: As you sweat continuously and don’t drink enough water, the interstitial fluid, from which your CGM patch measures glucose, becomes more concentrated because its water content drops. This can cause the sensor reading to drift away from your actual blood glucose value. At the same time, dehydration prompts your body to release stress hormones, which can raise your blood sugar.
If your symptoms don’t match what the sensor shows, it’s a good idea to do a fingerstick check for confirmation. Your sensor is a great tool for tracking trends, but you should also pay attention to your own feelings, like dizziness, dry mouth, or fatigue.
To prevent dehydration, drink small amounts of water throughout the day. Don’t wait until you're thirsty, and remember to drink before, during, and after exercise. One simple way to check your hydration level is to look at the color of your urine. Pale yellow usually means you’re well hydrated, while dark yellow or brown, means you need a hydration break. Also, keep in mind that what you drink affects your body. A cold sugary drink might seem refreshing, but it can spike your glucose quickly. In this case, plain water or zero-sugar electrolyte water is usually a better choice.
How to Store Insulin in Hot Weather
Insulin is a protein hormone that doesn’t tolerate extreme temperatures well.
Unopened vials or cartridges are typically stored in the fridge (2–8°C/36–46°F), and those currently in use can be kept at room temperature for a limited period, typically around 28 to 30 days for many insulins. Some types of insulin have stricter storage requirements, with a maximum room temperature of 25°C (77°F). Always check the storage instructions on your specific insulin package insert for the exact duration.
During the hot summer months, extra attention is required. One of the most common mistakes is leaving insulin in a parked car. On a sunny day, the temperature inside a car can exceed 50°C within an hour – enough to destroy the insulin’s effectiveness.
Whether you’re going to the beach, hiking, or just running errands, always carry your insulin with you. Never leave it in the car. A small insulated cooling pouch can be helpful, but don’t put the insulin directly on ice. Use a cloth or towel as a buffer to prevent freezing.
If you’re unsure whether your insulin has gone bad due to exposure to summer heat, it’s safer to replace it. Heat‑damaged insulin often shows no visible change, but you can tell if it's damaged by the unexpected blood sugar spike, which means your insulin doesn't work properly. Sometimes, however, there are some visible changes, such as floating matter, discolouration or cloudiness, which make things easier to identify.
Swimming and Water Activities with an Insulin Pump and CGM
Whether or not you can swim with your devices depends on their waterproof rating. This may differ from what you might expect. Some pumps and CGMs are made for swimming, while others can only handle splashes. Each manufacturer has different instructions, so it's important to always check your device's manual first. Here is ours, for the TouchCare Nano system.
Can you swim with the Medtrum TouchCare Nano patch pump?
Yes, as long as it is within its safe operating limits. When the pump base is connected properly to the reservoir patch and the CGM sensor is connected properly to the CGM transmitter, the TouchCare Nano pump and CGM patch can be used in still water up to 2.5 metres deep for up to 60 minutes. Swimming in a pool or a freshwater lake is a good example of this. Before getting in, ensure the adhesive is firmly attached. Also, leave the PDM and your phone somewhere dry, as the water rating only applies to the pump and CGM, not your controller. Additionally, we recommend checking your blood glucose level after about 30 minutes of water activity, and also checking the adhesive and device placement at the same time.
One small detail to be aware of: IP ratings are tested in still water. Diving in from a height or sitting under a pool jet creates stronger pressure than the test conditions, so consider the rating an allowance for swimming, not an all-purpose guarantee.
Ocean swims and sessions over 60 minutes: extra protection
Are you planning on staying for more than an hour, or are you going to swim in the ocean? Add some extra protection. A waterproof adhesive layer helps the patch stick better, which is useful because saltwater, sun and long periods of getting wet can weaken the adhesive. We recommend trying different tape products based on your personal needs or consulting your healthcare provider. On long days at the beach, it's better to take a break from swimming than to stay in the water all the time. After you swim, dry the devices with a clean towel. After swimming in the sea, wipe off any salt residue first. The system isn't designed for scuba diving because the pressure at depth far exceeds its specifications.
If you've seen waterproof cases for insulin pumps online, note that these are designed mainly for tubed pumps; for a patch system like the Medtrum Nano pump, the overlay is the equivalent.
Hot tubs, saunas, and hot springs: why to skip them
This one comes down to the Nano's own temperature limits. The pump and transmitter operate within the range of 5 to 40°C (41 to 104°F) . Hot tubs are at the upper end of that range, and saunas go far beyond it. Steam and prolonged soaking weaken adhesive faster than almost anything else, so it's not worth the risk. We do not recommend using the system in hot tubs, saunas or hot springs.
To avoid this, plan your visit for a patch-change day. Remove the old patch, then clean and dry your skin before applying a new one. The temperature limits will not be changed by any case or overlay.
Sunscreen, Heat, and Adhesive: Protecting Your Devices and Wear Sites
Your insulin pump and CGM patch are both precision electronic devices. Direct, prolonged sunlight can raise their surface temperature, which may affect internal electronics. When possible, keep your devices under your clothing or choose wear sites that are covered by your shirt.
Care should also be taken when applying sunscreen. Sunscreen, lotions, and toners leave an oily residue on the skin – and that’s a common reason for poor adhesive performance. The correct order is:
1. Clean the skin where you’ll place the device.
2. Make sure it’s completely dry.
3. Apply the device.
4. Apply sunscreen to areas outside the patch site, leaving 2–3 centimetres of space around the sticky edges.
Important care tips for adhesion and device maintenance:
• After exposure to water, dry the device surface immediately with a lint-free cloth.
• When changing devices, dry the surface and connection points with a lint-free cloth first. If you notice any discolouration or foreign material at the connection points, clean them with an alcohol wipe and allow them to air-dry completely before attaching the new device.
• After applying a new patch, avoid getting it wet or bumping it for a while, as the adhesive needs some time to reach its full bonding strength.
Also, be aware of the operating and storage temperature limits. The patch pump and transmitter within the temperature range of 5 to 40°C (41 to 104°F), and store from -10 to 55°C (14 to 131°F). The CGM patch works from 5 to 40°C (41 to 104°F), and storage from 2 to 30°C (35.6 to 86°F). Avoid leaving the devices in cars, on balconies, or in backpacks left in the sun or anywhere else that can create extreme local temperatures.
Preventing Low Blood Sugar During Summer Outdoor Activities
Summer activities like hiking, cycling, or team sports involve high energy use and lots of sweating, which can cause big swings in blood glucose. A smart monitoring plan helps:
• Check your glucose before you start to know your baseline.
• Check every 30–60 minutes during the activity.
• Always carry fast‑acting carbohydrates like glucose tablets or fruit juice to treat a low if it occurs.
Many people don’t realize that low blood sugar can occur hours exercise. After intense exercise, your muscles continue to use glucose to replenish glycogen stores, which can lead to hypoglycaemia 2–4 hours later. So it’s important to keep checking your glucose levels for a few hours after you finish, and definitely before you go to bed. If you’re thinking about adjusting your insulin dose around exercise, talk to your doctor first and never guess the numbers. There are natural ways to manage blood sugar, such as staying hydrated, eating balanced snacks, and pacing your activity, which are complements to your insulin plan, but not substitutes for medical advice.
Summer Diabetes Packing Checklist: Backup Supplies to Carry
When heading out for a summer trip, a well‑prepared kit can save you from many headaches. Here’s what to pack:
• Spare patch pumps and CGM sensors. Bring one or two extra, depending on trip length
• Blood glucose meter and plenty of test strips
• Urine or blood ketone testing supplies
• Fast‑acting glucose tablets or glucose gel
• Rapid-acting U-100 insulin, along with insulin syringes or pens
• Glucagon emergency kit
• Alcohol wipes for site cleaning and proper adhesion
• Physician instructions on insulin dosing if pump delivery is interrupted, and emergency contact numbers (including your healthcare provider's)
• Small insulated cooler – for storing spare insulin
• Charged power bank. If you use a phone app to manage your pump, remember that heat can drain batteries faster, so keep your PDM fully charged as a backup controller.
Before you leave, talk to your doctor about an emergency plan. If your pump stops working, what is your backup insulin schedule? How much rapid‑acting insulin should you take with meals, and what’s the basal replacement? Never decide these doses on your own. Even with reliable devices, patches can sometimes peel off or get damaged unexpectedly. Therefore, having a complete manual injection backup is a responsible precaution.
Sick Day Rules for Insulin Pump Users in Summer
Summer is also a peak time for stomach bugs. Vomiting and diarrhoea don’t just affect your eating – they can send your blood sugar on a rollercoaster and, in severe cases, raise the risk of diabetic ketoacidosis. Having a clear plan is essential.
• Get a written “sick day management plan” from your diabetes care team before you travel.
• Always follow your doctor's guidance on sick-day management, including adjusting insulin doses, checking glucose more often, and testing ketones if needed.
• Understand that even if you’re eating less, your basal insulin may still be needed. You'll know how to adjust from your doctor.
• Seek medical help promptly if vomiting, diarrhoea, or persistent high/low glucose continues.
Writing down and reviewing these diabetes sick day rules can help you stay safe when things don’t go as planned. And don’t forget to pack extra supplies, because illness can also affect how well your adhesive stays on.
Letting Friends and Family Know How to Help
Summer gatherings and group outings are frequent, and making sure the people around you know the basics of diabetes management can be a real lifeline in an emergency. Consider telling at least one friend or family member how to recognise typical low‑blood‑sugar signs, like dizziness, heavy sweating, confusion, or slurred speech. Besides, you should tell them where you keep your glucose tablets and how to use them.
It’s also helpful to give them a simple explanation of the patch pump and CGM sensor you’re wearing, so they understand these are medical devices for glucose control. You don’t have to provide technical details, just explain that they shouldn't remove the devices if you're unable to speak. This isn’t about asking for special treatment, but about taking responsibility for your own safety. A little awareness among your companions can make a big difference.
Ready for Summer, Wherever It Takes You
The Medtrum TouchCare Nano pump is a tubeless insulin pump with IP28 water resistance (2.5 m, up to 60 minutes), and the TouchCare Nano CGM sends glucose readings straight to your phone, so a swim, a hike or a beach day doesn't have to change your plans. Together they form the Automated Insulin Delivery (AID) system.
Questions about your devices? Our support team is here to help.
FAQ: Wearing an Insulin Pump and CGM in Summer
Q: Can I wear my Nano pump and CGM at the beach?
Yes, but keep these points in mind:
• Avoid leaving the devices in direct sun for long periods;
• Apply a waterproof adhesive overlay before entering the water;
• Pat the devices dry after swimming;
• Keep them away from sand, especially when changing patches.
• If you plan to be in the water for over 60 minutes or are swimming in the ocean, the extra overlay is recommended.
Q: What should I do if sweat makes my patch edges lift?
Prevention is best. Before applying, clean the skin with an alcohol wipe and let it dry completely. Some people use a skin barrier wipe to improve adhesion.
If the patch has already started to lift, it’s usually safer to replace it rather than trying to press it back down, because a lifted edge can let water and dirt in.
Q: My insulin was left in the heat – is it still safe to use?
If your insulin was left in a hot car or a backpack that sat in direct sunlight, it’s safest to replace it. Heat‑damaged insulin often looks normal, but it may lose potency. When in doubt, consult your pharmacist or doctor.
Q: Can I fly with my Nano pump and CGM?
Yes. A few things to remember:
• Request a pat-down instead of a full-body scanner, and ask for a visual inspection of your luggage rather than using CT imaging systems;
• For international travel, especially when crossing borders, you may need to present documentation of your medical condition. A customs declaration or medical passport confirming your use of a Pump and CGM can help if requested by customs authorities;
• Pack all your supplies, including their original packaging and a copy of your prescription, in your hand luggage.
For more questions, visit our FAQ page . We have answers to many common concerns about how to wear an insulin pump in different situations, as well as tips on diabetes management and supplies for travel.
About Medtrum
Medtrum is a medical device company dedicated to simplifying diabetes management. We develop tubeless insulin pumps and continuous glucose monitoring systems for people with diabetes, build tools that support healthcare professionals, and continue to explore the frontiers of artificial pancreas research.
