Educational explorer

Planning for Before, During and After Exercise

Build a complete glucose management plan for any session — insulin adjustment, carbohydrate strategy, and recovery carbs — across multiple glucose bands. Adapts to MDI, pump, and AID therapy. Includes before, during, and after guidance plus overnight considerations for evening sessions.

Important — about this tool

This is an educational explorer built from clinical trial data and real-world patterns. It models how algorithms and physiological principles behave on average — not how any individual system will behave for you. It is not a prescription, not a medical device, and must not be used as one. All outputs are for education and discussion only. Any changes to your insulin settings, device configuration, or diabetes management must be made with your diabetes care team.

Read the full GNL disclaimer · How GNL builds its tools and curates evidence

The Glucose Never Lies® Planning for Before, During and After Exercise — educational output only. Not a prescription.

Step 1 — Select your therapy

Choose the insulin therapy you are using. The exercise guidance will adapt to your system.

Understand how the calculation works In-depth explanation →

What this explorer does

This explorer generates a population-average exercise guide based on your therapy type, insulin on board, body weight, and session details. It covers what to consider before, during, and after exercise — and adjusts the guidance based on whether you use injections, a manual pump, or an automated insulin delivery system. The outputs are averages for the average person with these inputs, not a prescription for any individual.

You enter the planning inputs here. The output then gives you glucose ranges with the corresponding carbohydrate amounts for each range — so you can look at your CGM at the time and know what to do. This is a planning tool, not a real-time calculator.

The outputs describe average responses and general principles drawn from clinical evidence, including ISPAD 2022 consensus guidelines. They are not instructions — they are starting points for you to explore with your own data and discuss with your diabetes care team.

Before exercise: Carbohydrate amounts by glucose range, bolus reduction, AID mode activation
During exercise: Carbohydrate amounts by glucose range per 20-minute interval
After exercise: Mode return, meal bolus reduction, late-onset hypo monitoring
Overnight: Appears automatically for sessions after 4 pm — covers bedtime glucose, snacks, and basal adjustments

All carbohydrate values are based on your body weight and insulin on board. The heavier the insulin exposure at the time of exercise, the greater the carbohydrate requirement.

Step 2 — Enter session details

Enter the details of your exercise session. The output will show glucose ranges with carbohydrate amounts based on your insulin on board and body weight.

Glucose units

Exercise type

Intensity

Duration (minutes)

Time of day

Preferred option to prevent overnight lows

Body weight (kg)

Hypo risk profile (your usual pattern)

Preferred carbohydrate source

Bolus doses

Note the boluses you plan to have in the 9 hours before exercise. This is used to estimate insulin on board at the time of exercise.

Units

Time before exercise

Estimated IOB

—

IOB per kg

—

Phase 1

Before exercise

Phase 2

During exercise

Phase 3

After exercise

Phase 4 — Evening session

Overnight considerations

How to adapt next time

Select the scenario that matches what happened — the guidance below will show you what to adjust for your next session.

Copy your plan

Copy the text below to save, share, or take to a clinic appointment.

Enjoying the GNL Explorers? Help keep them going: