TL;DR
Movement is the fastest “correction tool” you have — not because it replaces insulin, but because it can supercharge the insulin already on board in real time. It also is great for stopping after-meal glucose spikes in their tracks if used proactively!
- 10–15 minutes after eating: a short bouts of movement can blunt post-meal spikes.
- When you’re high: if glucose is >10 mmol/L (≈180 mg/dL) and insulin is on board, 20 minutes of movement often lowers glucose by around ~2 mmol/L (≈40 mg/dL). (20 by 2 / 20 by 40)
- Stack it: used strategically, this can accumulate 30–60 minutes/day of health-promoting movement while improving Time in Range — without relying on extra correction insulin.
Why it matters: insulin corrections are slow and have a long “tail”. Short movement bouts are fast and typically fade within ~30 minutes — which often means lower late-hypo risk than stacking insulin when used appropriately.
The Mealtime Insulin Guide shows that adding 10–15 minutes of activity after meals can be a game-changer for improving time in range after eating all types of food.
Simple
Post-meal highs remain one of the toughest challenges in type 1 diabetes. Even with rapid insulin and the most advanced automated systems, glucose often rises steeply before settling — because injected insulin is too slow to match fast-absorbing carbohydrate.
That’s where movement changes the game. Done in short, targeted bursts, it can amplify insulin action and bring glucose back towards range faster and more predictably than waiting for a correction dose to land.
Companion deep dive:
Podcast: Episode 8: Activity Snacking to Increase Time in Range for T1D or quick YouTube Video
Medium
Insulin is in the wrong place (and too slow) — movement helps
In type 1 diabetes, injected or pumped insulin enters the systemic circulation rather than the portal vein. That mismatch contributes to post-meal spikes and can mean higher circulating insulin later than you’d ideally want. Also, how the absorption of insulin is very slow in comparison to delivery from the beta-cells into the portalk vein!
Movement is the “helping hand” that can close the timing gap: it shifts blood flow and increases muscle glucose uptake while insulin is still catching up.
How does activity supercharge insulin?
Activity enhances insulin effectiveness in four key ways:
- Faster absorption: activity increases blood flow to the skin, accelerating insulin uptake from the injection site into the bloodstream.
- Non-insulin mediated glucose uptake helps too: movement opens additional pathways for glucose to enter muscle even when insulin action is imperfect.
- Enhanced delivery: activity increases blood flow to working muscle, meaning insulin reaches muscle cells more efficiently.
- Reduced breakdown: insulin is normally cleared substantially via the kidneys. During activity, blood is redirected towards muscle, reducing clearance and making insulin last longer.
Rule of thumb: in practice, many people see a meaningful drop from a short bout. The flagship protocol is 20 by 2 (or 20 by 40): 20 minutes of activity lowers glucose by around ~2 mmol/L (≈40 mg/dL) when insulin is on board.
20 by 2 / 20 by 40 (full protocol + downloads + EASD materials)
In mg/dL
Philosophy in action (Grace)
Here’s one example of the philosophy in action — Grace showing how a bit of movement can rapidly bring glucose back into range.
Deep
Between meals, insulin corrections are brutally slow. As you saw in Correction insulin, it can take about three hours to get back under 10.0 mmol/L (180 mg/dL), and around four hours to get to ~5.5 mmol/L (100 mg/dL).
How fast is movement compared with a correction?
This graphic shows that a 10-minute burst of exercise starts working immediately. By ~10 minutes glucose is already dropping, and by ~30 minutes you’re typically back into target.
Even better: most of the glucose-lowering effect is gone by ~30 minutes. That means you can repeat short bursts if needed, without the same “insulin tail” that drives late hypos.
That speed is why activity snacking is a core lever inside Dynamic Glucose Management, we call it GAME.
Practical
A) Post-meal: 10–15 minutes to shape the spike
- When: ~10–15 minutes after eating.
- What: easy walk, light cycling, stairs, light household movement.
- Goal: reduce the peak and shorten time above range while insulin is still catching up.
B) When above 10 mmol/L try 20 by 2 OR if above 180 mg/dL try 20 by 40
- When: if glucose is above 10 mmol/L (≈180 mg/dL) and insulin has been given in the last ~4 hours.
- What for 20 minutes: walking, cycling, light circuits, even household chores all count.
- Safety: avoid if glucose is >15 mmol/L (≈270 mg/dL) with ketones present. Always check you have insulin on board.
Full protocol: 20 by 2 / 20 by 40
Exercise is different (don’t confuse them)
This page is about short, strategic movement to improve Time in Range with minimal additional hypoglycaemia risk. Exercise is different: sessions that are ~30 minutes or longer and/or more intense can carry significantly higher complexity and hypoglycaemia risk, and need a dedicated framework.
Go to the Exercise guide (structured training + safety planning)
References
What’s next
Next step: Hypoglycaemia.
