How the Simulators Work
Food, insulin, and exercise all operate at different speeds — and those change when they overlap. These tools make those invisible processes visible so you can learn to anticipate them.
Every chart shows shape, not numbers.
Each chart shows relative effects — how a factor moves blood sugar compared to a flat baseline. No actual blood sugar numbers appear, because everyone’s starting point is different. The shape of the curve is what matters: when it peaks, how long it lasts, and how it overlaps with other effects.
Each simulator is a sandbox for one concept. Start with the individual simulators to build intuition for each effect. When you’re ready, the 24-Hour Simulator lets you combine everything and see how they interact across a full day.
Every curve has a color and a stroke.
So a chart still reads without its colors. The chips under each chart show the same stroke as the curve they switch on and off.
- Blood sugar — the one heavy, solid, unshaded line: every effect added together.
- Insulin effect — even dashes, shaded below the middle line while a dose is working.
- Carb effect — dash-dot, shaded above the middle line while a meal is absorbed.
- Basal effect — a solid line, shaded, for a change in a pump’s basal rate.
- Doses, meals and rate changes — a dot on the middle line where it happened, in the colour of the curve it starts.
- Exercise effect — dots, for the workout’s own pull while it lasts.
- Post-exercise effect — long dashes, for the extra insulin sensitivity in the hours after.
- Dawn effect — dash-dot-dot, shaded above the middle line, for the glucose the liver releases on waking.
- Overnight sensitivity — long and short dashes, for the extra insulin sensitivity through the night after a workout.
Try things you wouldn’t try in real life.
These simulators let you experiment with diabetes-management scenarios and see how they play out — while keeping you completely safe. Build your knowledge of what works, what doesn’t, and how to handle different situations before you need it for your own management.
Four things move blood sugar.
-
Insulin
Lowers blood sugar — slowly
Insulin lets your cells take glucose out of the blood. Rapid-acting insulin starts working about 10–15 minutes after a dose, peaks around 75 minutes, and keeps working for up to 6 hours.1 It never acts instantly, so where you are on that curve when you eat or exercise changes everything.
Pump users also run a basal rate — a steady trickle of the same rapid-acting insulin all day. Lowering it before a workout (a temp basal) changes what the pump delivers straight away, but not what is working: the insulin already given is still absorbing, and a lower rate cannot take it back. After an hour, only a fifth of a basal rate change has happened; and it takes two hours for half of that change to take place, with the rest of the change happening over a few more hours. That is why a temp basal is set well before the exercise it is meant to cover. What the chart shows is how that change compares to your usual rate.
-
Carbs
Food raises blood sugar
Carbohydrates digest into glucose and enter the bloodstream. Fast-absorbing carbs (juice, glucose tablets) hit quickly. Complex carbs, fat, and protein slow the process down — which is why the same amount of food can produce very different curves depending on what’s in it.
-
Exercise
Movement lowers blood sugar, and keeps lowering it
Aerobic exercise pulls glucose out of the blood for as long as it lasts, because working muscles take it up directly. Afterward, those muscles keep refilling their stores for hours, so you stay more insulin-sensitive long after you stop.2
-
Your Liver
Stored glucose can raise blood sugar
Your liver holds a reserve of glucose and releases it when stress hormones tell it to. Short, intense anaerobic efforts — sprints, heavy lifts — trigger adrenaline, and blood sugar climbs before it falls.2 The same release is behind the early-morning rise many people see before breakfast.