Fitness + T1D: Why I Run High During Workouts (Adrenaline) and Crash Low After — and What Helps Me

If you live with Type 1 Diabetes and you work out, you already know it’s not always as simple as “exercise lowers blood sugar.”

For me, workouts can do both.

I do hot pilates, weight lifting at the gym, and sports — and depending on the day, I’ll either spike high during the workout (hello, adrenaline), or crash low after (the post-workout drop). Sometimes I get the lovely combo: high during, low after. And if you’ve ever dealt with that, you know it can mess with your confidence and self esteem fast. You start questioning everything: what you ate, what you bolused, whether you should even work out today.

This is what the "Spike" could look like during activity.

Why I go high during workouts (especially sports + hot classes)

When I’m doing hot pilates (think cycling class in the sauna) or playing sports, my blood sugar can rise — not because I did something “wrong,” but because my body is doing what bodies do under stress.

Adrenaline (and other stress hormones) can tell your liver to dump glucose. It’s like your body is preparing for a fight-or-flight moment. That spike is super common with:

• Sports / competition

• Hot, intense classes

• Anything that gets your heart rate up fast

So if you spike during activity, you’re not alone, and you’re definitely NOT failing.

Why I crash low after

Then comes the part that can feel unfair: the workout ends… and the drop hits later.

After exercise, your muscles are basically like, “Thank you, we’ll take that glucose now.” Your insulin sensitivity can increase, and your body can keep pulling glucose into your muscles even when you’re done moving. That’s why the low can happen right after, 1–3 hours later, or even later depending on the intensity.

What makes me spike (and what doesn’t)

For me, the workouts that make me spike high are hot pilates and sports. That’s when the adrenaline hits, the intensity is up, and my body acts like it’s in fight-or-flight.

But what’s interesting is that my numbers don’t normally spike when I’m working out at the gym. Weight lifting and regular gym sessions feel more predictable for me — it’s the heat + intensity + adrenaline combo that really sends my blood sugar up.

How I prevent the crash after (what actually helps me)

The biggest thing that helps me avoid the post-workout low is eating right after I’m done — even if I don’t feel low yet.

I try to get protein + carbs in as soon as possible. Something simple like:

• Rice + meat (my go-to when I can eat a real meal)

• A banana if I can’t do a full meal right away

That post-workout fuel makes a huge difference for me, because the crash can come after the adrenaline wears off — and I’d rather support my body before it drops than chase a low later.

My Omnipod / pump mindset

I’m not here to give “perfect numbers” advice — I’m here to share what helps me manage the pattern without spiraling.

1. I plan for the crash, not just the workout. The workout is only half the story. The after-effect is real.

2. I don’t rage-correct the adrenaline high. If I correct too aggressively, I’m basically setting myself up for the post-workout low to hit harder, and all the insulin to hit at once which doubles the low.

3. I watch the “after” window like it’s a second workout. The crash can sneak up when you think you’re done, but sometimes it doubles back depending on how much insulin is given and when it was given.

4. I keep fast sugar nearby even if I “feel fine.” Because I’d rather be prepared than panicked.

5. I give myself credit for showing up. Managing T1D while working out is a mental battle too.

If this is you

If you run high during workouts and crash low after, you’re not broken. Your body isn’t “doing it wrong.” You’re dealing with hormones, intensity, heat, insulin sensitivity, and timing; all at once.

Question for you

What kind of workouts make you spike high — and what helps you prevent the crash after?

If you don’t have support right now, you can borrow mine. You’re welcome here.