So I bike for exercise, and I bike commute weather permitting. Used to run until I started getting arthritis in my hips in my 50s so I shifted to a lower-impact routine. All aerobic stuff—steady intensity w/heart rate around ~120. Effect varies by time of day, but barring extraordinary circumstances this has always always always exerted a downward pressure on my BG. For some reason I don’t see as much of that effect in the morning, but it increases throughout the day and late afternoons my homeward ride can drop me 30 points or so. I’ve been T1 since 1983 and as long as I’ve had it, this has been my pattern.
For example, this a.m.'s ride to work. Starting bg 127 with a couple units of IOB on board. Arrive at work: 165, trending up. Wut??? Recent midday rides have had a similar upward rather than downward effect. Started noticing this over the last few weeks. Like going for an early afternoon ride on a Saturday is actually making my BG increase 20 pts. All of a sudden I’m having to do a correction after exercise, which for me is nuts. I mean, I know some people experience this when they do intense strength training routines, but that’s an adrenaline thing, which I don’t think this is, unless I’m suddenly going all adrenal at exercise I’ve been doing for years that always had the opposite effect. Really confusing and really annoying. I’ve noticed it happening in the past when I ride in really cold temps, <30° F, and I think the adrenaline effect IS kicking in then, but this doesn’t fit any of the patterns I’ve gotten used to over decades.
Makes me wonder if there’s something weird going on metabolically but I don’t know what it could be. Just aging? Anyone else experience a change like this?