If you’re living with type 1 diabetes (T1D), it’s important to remember that exercising can impact your blood glucose levels – both while you’re working out, and for several hours afterwards.
What happens to your blood glucose levels during and after exercise will depend on the balance between a few factors:
- the amount of insulin you have on board
- the timing of exercise (when you do it, and how long for)
- the type of exercise (aerobic, anaerobic or mixed)
- your blood glucose level before doing the activity
- your food and fluid intake.
To help you learn your body’s response to exercise, it’s best to check your blood glucose levels before, during (every 30 minutes or so, if possible) and after exercise – including tracking it every couple of hours afterwards.
Continuous glucose monitors (CGMs) are a great tool to help you identify how exercise affects your glucose level patterns. They also give you information about what happens during and after exercise, including overnight.
Being aware of your glucose levels around exercise will make it easier to see trends, and will guide you and your diabetes team when developing your management plan.
Types of exercise and their impact on blood glucose
Different types of activity have different effects on blood glucose levels. Here’s a general guide to some common kinds of activities.
| AEROBIC EXERCISE | Aerobic exercise includes activities like swimming, jogging, cycling and walking. These usually lower blood glucose levels during and after the activity. |
| MIXED EXERCISE | Mixed exercise includes team sports such as soccer, basketball, netball and hockey. These activities may result in no change to glucose levels, or they might increase or decrease during the activity, then lower afterwards. |
| ANAEROBIC EXERCISE | Anaerobic exercise includes activities like sprinting, weight lifting, strength and power sports. These usually push glucose levels up initially, but can still lower them afterwards. This happens because your body releases high levels of adrenalin that trigger your liver to break down stored glucose and release it into your bloodstream. |
Videos: preventing lows, and unexplained hyperglycaemia
Watch our short videos to learn more about how physical activity can influence blood glucose levels when living with T1D.
Video: Preventing lows
The below video explains how insulin and glucagon control the uptake and production of glucose, and how they function during exercise.
Video: Unexplained hyperglycaemia
Learn why blood glucose can rise during or after exercise, and what people with T1D should be aware of while while working out.
