Insulin and exercise can feel like a nightmare combo. One wrong move, and you’re either crashing or sky-high. But, and it’s a big but — you can lift weights, run, cycle, and build muscle. You just need to understand how your insulin works with your body.
And quick note — I’m not a doctor. Always check with your endo before changing your routine.
Why Many Type 1s Fear Exercise
We’ve all been there. You’re ready for the gym, then bam — your blood sugar tanks halfway through. Or you finish and shoot up to the stratosphere. It’s soul destroying. After a few of those experiences, you start thinking, “Why even bother?”
But fear keeps you stuck. Exercise is not your enemy. Misinformation is.
The Dynamic Dance: Insulin and Glucose
Think of insulin and exercise as dance partners. Insulin lowers sugar; exercise uses it for energy. But when you move, your body gets extra sensitive to insulin. That’s why the usual doses might hit harder than expected.
Basal and Bolus: Know Your Team
Basal insulin runs quietly in the background. Bolus handles meals. During workouts, bolus usually causes the drama. So, most people tweak that one first. Long sessions, though? Basal can join the chaos too.
Pre-Workout Insulin Adjustments
Planning a workout? Cool. Trim your bolus a bit.
Many of us T1s drop it 25–50% depending on intensity.
If you’re training right after a meal, maybe even skip it. Experiment slowly. Every body is different.
Carbs Are Not the Villain
You’ll need them. Have a small, fast carb before you train — a banana, glucose tab, or half a sports drink.
Going long? Sip 10–20g carbs every 30 minutes. No shame in fueling up. You’re not “cheating.” You’re trying not to go hypo.
Check During the Chaos
Keep an eye on your numbers. Every 20–30 minutes if you can.
If you start dipping toward 4 mmol/L, stop. Treat it. Then keep going once you’re stable.
If you spike? Pause, breathe, adjust. Don’t panic.
After the Sweat: Insulin Tweaks
Post-workout, your muscles suck up glucose fast. You’re more sensitive. Cut your post-meal bolus about 20–30%.
Watch for delayed hypos a few hours later — they love a late-night surprise.
Weight Training Isn’t Off-Limits
Lifting won’t break you. It builds muscle and confidence.
Yes, stress hormones can make sugars spike, but that’s short-term. A little trial and error will help you figure out what works for your body.
Cardio: The Long Game
Endurance workouts can drain you — and your glucose.
That slow burn means you might need more snacks and less insulin.
Don’t be scared to pause for carbs. The treadmill will still be there.
HIIT and CrossFit: Wild but Worth It
High-intensity workouts love to play games with your blood sugar. Adrenaline spikes you up; then you might crash later.
Sometimes you’ll need a tiny bolus after training.
Just test, learn, adjust. That’s the secret sauce with insulin and exercise.
Hypos and Hypers: Stay Ready
Low? Treat it fast — 15g carbs, wait 15 minutes, retest.
High? Stop, correct, hydrate, breathe.
Don’t ignore either one.
Night Training: Handle with Care
Evening workouts can mess with overnight levels.
Try reducing your basal or adding a small bedtime snack. If you use a CGM, keep those alarms on. Sleep is sacred.
Smart Fueling = Happy Muscles
Eat balanced.
Before: carbs + a bit of protein.
After: carbs + protein + healthy fat.
Avoid heavy fat meals pre-workout — they slow digestion and delay insulin action.
Match Insulin to Intensity
Harder workouts = bigger adjustments.
Create a quick reference for yourself:
- Light cardio → small reduction
- Moderate training → medium cut
- Heavy or long → major drop
Keep notes. Over time, you’ll find your rhythm.
Mindset Over Fear
You’ll mess up sometimes. You’ll go low, or spike, or feel frustrated.
That’s part of the process. You’re learning how your body works.
The goal isn’t perfection — it’s progress.
My Example Week
Monday: strength — cut bolus 30%, snack 15g before.
Wednesday: HIIT — small bolus after, watch for late drops.
Friday: tempo run — cut more, snack mid-session.
Sunday: long cycle — constant carb drip.
Every week is data. That’s how you master insulin and exercise.
Work With Your Team
Bring your data to your endo. They’ll help you adjust and stay safe.
Never go solo if you’re unsure. It’s teamwork, not guesswork.
Tech and Tools Help
CGMs, pumps, sensors, alarms — use them.
Carry glucose tabs. Wear medical ID.
Preparation = freedom.
Know When to Rest
If you feel shaky, dizzy, or “off,” stop.
Your body isn’t being dramatic. It’s protecting you.
Rest days build strength too.
Encouragement
You can do this. You can lift, run, box, dance — whatever you love.
You are not fragile. You are powerful, adaptable, and capable of figuring this out.
Call to Action: Mindset Reset Kit
Still scared to move because of the what-ifs?
Grab my Mindset Reset Kit.
It helps you drop fear, rebuild confidence, and start living like the strong, unstoppable human you are — insulin and exercise included.
👉 Click here to grab your kit now.
Outside Read
Beyond Type 1 – Exercise and Type 1 Diabetes
Until next time,
Pete
