Swimming with CGM: Waterproofing and Sensor Protection

Can You Swim with a CGM?

If you wear a continuous glucose monitor (CGM) and love the pool, lake, or ocean, you may wonder whether your device can handle the water. The good news is that most modern CGM sensors are water-resistant — but there's a big difference between water-resistant and fully waterproof. Understanding that distinction, and taking a few protective steps, can help you swim confidently without losing your sensor or your glucose data.

Understanding CGM Water Resistance Ratings

Most CGM sensors on the market carry an IP (Ingress Protection) rating that tells you how well they resist water. Common ratings include:

• IP27 or IP28 – Protected against immersion in water up to 1–3 meters for 30 minutes to 8 hours
• IP67 – Dust-tight and can withstand immersion up to 1 meter for 30 minutes
• IP68 – Dust-tight and can handle deeper or longer immersion

Popular sensors like the Dexcom G7, Libre 3, and Medtronic Guardian 4 are all rated for water exposure, but none are designed for scuba diving or extended deep-water submersion. Always check your device's specific guidelines before heading into the water.

The Real Challenge: Keeping Your Sensor Attached

Water resistance doesn't protect against one of the biggest swimming-related CGM problems — adhesive failure. Chlorine, saltwater, sweat, and friction can all loosen the adhesive that holds your sensor to your skin. A sensor that peels off mid-swim is not just costly; it's a safety concern for people who rely on real-time glucose data.

Here are the most effective strategies to keep your CGM in place while swimming:

1. Use Overwrap Adhesive Patches

Specially designed overlay patches made from materials like Kinesio tape, SkinTac, or products from brands like Skin Grip, Ovesite, and Dexcom's own patches can be applied over your sensor to reinforce the bond. These patches come in various shapes to fit specific CGM models and are a go-to solution for active swimmers.

2. Prep Your Skin Properly

Clean, dry, and oil-free skin dramatically improves adhesion. Before applying your sensor:

• Wash the area with soap and water
• Wipe with an alcohol swab and let it dry completely
• Consider applying a skin-prep wipe or barrier film like Skin Tac or Mastisol

3. Choose the Right Placement

The upper arm and abdomen are the most common sensor sites. For swimming, the upper arm may experience less friction from swimwear and movement. Avoid placing sensors in areas where a swimsuit strap or waistband will constantly rub across the adhesive.

4. Time Your Sensor Changes Strategically

A fresh sensor has a stronger adhesive bond than one that's been on for several days. If possible, plan longer swim sessions for the early days of your sensor's wear period when adhesion is at its strongest.

What About Your CGM Receiver or Phone?

Remember that your CGM system includes more than just the sensor. Transmitters, receivers, and smartphones that receive your glucose data may not be waterproof. Most transmitters are water-resistant but should not be submerged. Check your specific transmitter's IP rating. For your phone or receiver, keep it on the pool deck in a waterproof case or pouch to avoid damage while staying close enough to maintain Bluetooth connectivity.

Managing Glucose Accuracy During Swimming

Physical activity, including swimming, can affect blood glucose levels and CGM accuracy. Vigorous swimming can cause your glucose to drop, while competitive swimming or water polo may cause it to rise initially due to adrenaline. Be aware that:

• CGM readings may lag behind actual blood glucose during rapid changes
• Cold water can sometimes affect sensor performance
• Always carry glucose tabs or snacks in an accessible, dry location at the pool

After Your Swim

Once you're done swimming, gently pat (don't rub) the sensor area dry. Check the edges of your adhesive for peeling and reapply an overlay patch if needed. If you notice irritation under the sensor, give your skin a break and consult your diabetes care team about alternative sites or adhesive products.

Final Thoughts

Swimming with a CGM is absolutely achievable with the right preparation. Invest in quality overlay patches, prep your skin carefully, and know your device's water resistance limits. With these steps, you can enjoy the pool or ocean while keeping your glucose monitoring right on track.