Temp Basal Simulator
For pump users: see how adjusting your basal rate around exercise affects blood glucose.
Insulin pumps deliver basal insulin as small, continuous pulses of fast-acting insulin. A temporary basal rate lets you reduce or increase this delivery for a set period of time.
This chart is designed to help you visualize how adjusting your basal rate before, during, and after exercise changes insulin delivery and blood glucose — especially when combined with food and the glucose-lowering effect of exercise itself.
Pay attention to:
- What happens when you reduce basal too late before exercise?
- What happens when you reduce it too much or too early?
- How does food interact with the temp basal effect?
What's happening here?
On insulin pumps, basal insulin is delivered as small pulses of fast-acting insulin. Though not measured as "insulin on board" like with a bolus, this fast-acting basal insulin still works faster during activity.
- If basal is reduced too late, you may have too much insulin on board.
- If reduced too much or too early, your blood sugars may go high before exercising.
- Eating carbs before or during exercise can offset some of the insulin on board.
During exercise, muscles can absorb glucose by themselves, causing blood sugars to drop even with no insulin on board.
After exercise, insulin sensitivity can remain elevated for up to 24 hours, which could cause lows using the same amount of insulin as usual.
Applying this to your own life
When exercising, look at how the timing and percentage decrease for a temp basal changes blood sugar similar or different to what you notice in this chart. Look at a CGM or test your blood sugar every 30 minutes.
As you make observations, keep notes on what different temp basals result in and how carbohydrates can be used to counteract some of that insulin.