I am still having a lot of fun with my CGM (continuous glucose monitor). I recommend using one for a couple of weeks. They are a great way to learn about how your body responds to different foods and activities, as well as how your blood glucose levels change over 24 hours.
For me, it has been a case of putting theory into practice - there is nothing better than seeing, firsthand, what you have read about.
I participate in a polar plunge every Sunday morning with a great group of women - we call ourselves The Ocean Church. We swim right through winter, rain or shine and this Sunday was a doozie! A basting cold southerly, snow further south and sea spray cold enough for immediate brain freeze.
So what would this do to my blood glucose levels? You can see my immediate response in the CGM screenshot below (my swim occurred at ~9:25 am).
- Initial Dip: Cold water drives glucose out of my blood into my muscles for shivering and thermogenesis. This drops glucose levels on the CGM.
- Stress Hormone Surge: The release of adrenaline and cortisol prompts the liver to release glucose into the bloodstream rapidly. The rebound you see to 6.1 mmol/L is this stress response.
The overall effect is a “V-shaped” curve (dip then rebound), which is a classic physiological response to cold stress and indicates that my body is functioning well.
So yes, a cold plunge doesn’t just energise you; it gives your blood sugar a rollercoaster ride that shows just how resilient your body really is (and it’s supposed to be good for you!).
A cold walk back home, followed by a warming shower and a hot coffee - Bliss!
Oh, and if you would like to join us in a Sunday polar plunge ❄️ 9:30 am, Brighton Back Beach, Dunedin, all welcome 😀