I’ve been meaning to try a CGM device for a while, mainly to understand my body better and also type 2 diabetes runs in my family.
What I’ve learned is that my body clears glucose spikes very quickly but it does on occasion spike over 140 mg/dL when I have something very sugary (rarely for more than an hour or two). The optimal level is for blood sugar to stay under 110 mg/dL, according to Levels, after eating. So despite a good fasting glucose rate, I think the spikes show that there’s been some loss of insulin sensitivity. The book that’s helped me understand this the most are Jason Fung’s books which I highly recommend.
Things That Spike My Blood Levels
Drinking Coffee When I Haven’t Slept Well
I think my body is just more susceptible to blood glucose rises when I don’t sleep well but I definitely noticed a pretty significant spike when I’m drinking coffee during a tired day.
When I’m drinking coffee on a normal day, there’s zero to negligible impact from drinking coffee.
Sauna and Being Dehydrated
I use saunas daily and you’ll see marketing materials constantly spout the benefits of how saunas will change your life. While I think it’s good to be skeptical about the supposed benefits on the websites of sauna providers (biased), I do think that there are a lot of benefits to using saunas regularly. Rhonda Patrick is one of the better known proponents. For example, your body starts producing heat shock proteins (it’s a stress response protein) which increases your glutathione levels, looks for free radicals, and protects the protein’s 3D structure (this becomes more of an issue as you age). For infrared saunas, you get the added advantage of enhancing your mitochondria. I use both dry saunas and infrared saunas. I generally don’t use steam saunas.
After I got my CGM, I noticed that when I use the infrared sauna for 45 minutes straight, my blood glucose spikes very high and then also comes back down just as quickly. I usually don’t hydrate during the sauna session — only before and after because I don’t like taking anything with me (including clothes!) except a towel into the sauna. You can learn more why that might happen here.
I’ve read in various places that extreme heat in the sauna can cause similar effects to exercising. You get more blood circulating, more sweating (causing dehydration), a higher heart rate and so on. Stress hormones (cortisol and adrenaline) get released (as in exercise) which causes an increase in the blood glucose level that’s circulating in your system.
After seeing my glucose spike, I decided to try and hydrate during my sauna sessions by taking a large thermos with me into the sauna. It made a big difference — I’ve noticed that the spikes are moderate now and they also go up much slower.