10 Tips to Optimise Time in Range: AID Systems

These strategies draw on the best available evidence across all AID systems. They are starting points for exploration and discussion with your diabetes team — not universal prescriptions. What works well on average may need adapting to individual physiology, lifestyle, and system.

Prefer to listen? Episode 6: Ten Tips to Optimise Time in Range with AID covers this material in podcast format.

1. Food and insulin: three balanced meals and post-meal movement

Three balanced meals — with consistent timing and composition — tend to produce more predictable glucose patterns than irregular eating or erratic meal sizes. This matters particularly for AID systems, which learn from recent history: inconsistency makes the algorithm’s job harder.

Adding 10 minutes of light physical activity after eating helps match the timing of peak insulin action with the glucose entering the bloodstream from a meal — smoothing out post-meal spikes that even the best algorithms can struggle with.

The mechanism here is insulin sensitisation: movement activates GLUT4 transporters in muscle independently of insulin, enhancing glucose uptake at precisely the moment it is needed most.

2. High fat and protein meals: “Find out before you fiddle”

Principle credited to Francesca Annan RD

Meals high in fat and protein produce a different glucose response pattern compared to carbohydrate-dominant meals. Fat delays gastric emptying and can induce a degree of insulin resistance, potentially leading to prolonged elevated glucose hours after eating — sometimes well into the night.

The recommended approach is to observe first: watch what actually happens with your CGM data across several similar meals before adjusting insulin strategy. Once the pattern is established, many people find that modest additional insulin — explored cautiously in small increments, discussed with the care team — helps manage the delayed glucose rise.

“Find out before you fiddle” captures the principle well: pattern recognition before action.

3. After-meal spikes: insulin timing and absorption site

Even with AID, post-meal glucose spikes are one of the most consistent challenges. Two factors — timing and absorption site — are within user control and can make a meaningful difference.

Timing: insulin given approximately 15 minutes before eating tends to reach its peak effect more closely aligned with the glucose rise from the meal. The exact optimal timing varies by person, meal, and starting glucose — but for many people, giving the bolus slightly ahead of eating reduces peak spike height.

Absorption site: the abdomen and arm are generally the fastest absorption sites for subcutaneous insulin. Injecting into these sites — rather than the thigh or buttocks — means insulin reaches the bloodstream more quickly.

The mechanism: in type 1 diabetes, subcutaneous insulin does not enter the portal circulation directly (as insulin from the pancreas does). This means insulin must first circulate systemically before reaching the liver to regulate hepatic glucose output — creating an inherent lag. Site and timing choices are the most accessible ways to partially offset that lag.

4. 3 every 30: breaking up sitting

Prolonged sitting increases insulin resistance progressively. Breaking up extended sitting with three minutes of light movement every 30 minutes is a well-studied intervention — and the effect on time in range is measurable.

Evidence suggests this pattern of light movement interruptions can improve time in range by around 14% on average compared with uninterrupted sitting. The mechanism is the same as other activity-based strategies: regular muscle contraction activates GLUT4 transport and reduces the build-up of insulin resistance over the course of a sedentary day.

Setting a regular reminder — or using a watch or phone — to stand and move briefly is one of the simplest high-impact strategies available to AID users.

5. 10 by 2 (mmol/L) or 10 by 30 (mg/dL): short activity to address elevated glucose

Ten minutes of moderate activity tends to lower glucose by around 2 mmol/L (or 30 mg/dL) on average. This is a shorter version of the 20 by 2 / 20 by 40 principle — and a practical tool for quickly bringing glucose back towards range when it has risen.

The response varies by individual, insulin on board, activity type, and current glucose level. Many people find this a reliable rule of thumb to start with, then refine based on what their own CGM data shows.

6. 50/50/20: exercise insulin adjustments for injections and standard pump therapy

For people on multiple daily injections (MDI) or standard pump therapy (not AID), a structured approach to insulin reduction around exercise tends to reduce glucose swings:

• 50% insulin reduction for the meal before exercise (within approximately 2 hours).
• 50% insulin reduction for the meal after exercise.
• 20% insulin reduction overnight (or 20 g of carbohydrate, or 20 g of protein) to manage the delayed insulin-sensitising effect of exercise.

These are average starting points for discussion with a diabetes care team — not fixed rules. The right adjustment depends heavily on exercise type, duration, insulin on board, and individual physiology.

7. T25/T25: exercise insulin adjustments for AID users

For AID users, the equivalent framework is T25/T25:

• First T25: in the approximately 2 hours before exercise, ensure a 25% reduction in insulin for any meal within that window, and start the exercise target (activity mode / higher target) 1–2 hours before the session begins.
• Second T25: stop the exercise target as soon as the session ends, and consider a 25% reduction in insulin for the meal after exercise.

The rationale: AID cannot reverse insulin already delivered. Reducing what goes in before exercise — by adjusting the meal bolus entry — is more effective than relying on the algorithm to reduce delivery after the fact.

8. CGM application and care: the SLO ARSE technique

CGM sensor accuracy is influenced by technique. A consistent application approach improves first-day accuracy and overall sensor performance.

Key principles: apply the sensor slowly and gently, with the arm relaxed and the skin elevated slightly off the muscle. Many people find that inserting the sensor the day before relying on it fully improves first-day readings — giving the interstitial fluid time to equilibrate with the new sensor.

Good CGM technique is a simple but often underestimated factor in overall time in range. Poor first-day accuracy can lead to unnecessary interventions that carry their own glucose consequences.

9. Site management: rotation and skin care

Regular rotation of insulin delivery sites — every 2–3 days for infusion sets and pump sites — preserves the tissue and maintains consistent insulin absorption. Lipohypertrophy (the build-up of fatty tissue from repeated injections into the same site) can significantly reduce insulin absorption and introduce unpredictability into glucose patterns.

A simple rotation chart or pattern — moving systematically around the abdomen, arms, or other approved sites — reduces the risk of over-using any single location. Skin care around sensor and infusion sites matters for comfort, adhesion, and tissue health over time.

10. Alcohol management

Alcohol affects glucose regulation through a distinct mechanism: it inhibits gluconeogenesis in the liver (the process by which the liver produces glucose from non-carbohydrate sources). This means the liver’s ability to raise glucose during a falling trend is blunted — and hypoglycaemia risk can remain elevated for many hours after drinking, particularly overnight.

The physiological consequence is that less insulin may be needed when alcohol is consumed, especially overnight. Many AID users find that enabling an activity or exercise target before going out — and keeping it active through the night — helps mitigate this risk.

Keeping fast-acting carbohydrate accessible and monitoring glucose more attentively while drinking are widely recommended precautions. Discussing an individual approach with a diabetes care team is particularly valuable here, as alcohol responses vary considerably between people.

Related reading

• Skincare for type 1 diabetes: a guide to site care and adhesion
• AID systems: comprehensive guide
• AID systems and exercise: key guidance