Aerobic Exercise, Lifting and Glucose With Type 1 Diabetes
Why might a bike ride lower my glucose more than squat sets? If you've heard that exercising always means lowering your glucose, seeing different effects can be confusing.
Understanding Aerobic and Anaerobic Exercise
First off, let's talk terminology—aerobic and anaerobic describe how your body supplies energy during exercise. Those labels alone cannot predict your glucose response. Most exercises use components of both. In a mixed workout, time spent sprinting, resting or lifting can change the glucose pattern. Those details matter more than the class name alone.
What the comparison trial found
In a study involving twelve people with type 1 diabetes, Yardley and colleagues compared resistance exercise, aerobic exercise and a resting control on separate days. Average glucose fell during both exercise sessions, with a larger initial decline during aerobic activity. Later glucose patterns also differed. Read the study.
These findings challenge the idea that resistance training always increases glucose. They come from specific sessions involving only a small group of people. The results are useful, but they don't promise you the same experience in your next workout.
Important individual factors
The 2026 ADA/EASD consensus outlines several factors influencing glucose responses to activity: exercise type, intensity, duration, circulating insulin, starting glucose and recent food.
Describe your workout
At your next review, describe the beginning, main work and finish of your session. For example: a light warm-up ride, strength exercises with long rests, and a rowing finisher.
Include meal and insulin timing as well. Note when glucose direction changed—during the warm-up, between exercise blocks or after the session. Record any low treatment or changes made under your established plan.
Activity order can matter
A small crossover trial found different glucose responses when resistance training came before versus after aerobic exercise. Neither order ensures that a low won't happen. Read the exercise-order study.
Plan for your automated insulin delivery system
Discuss your automated insulin delivery system and planned exercise with your diabetes care team. Glucose targets differ between products. A higher exercise target intended to reduce lows may not suit an activity that usually raises your glucose. The EASD/ISPAD statement covers planning for specific systems.
Stay prepared for low glucose
Carry your glucose-monitoring supplies and usual low treatment during your sessions. If glucose is low or you develop low-glucose symptoms, pause and follow your treatment plan. Frequent interruptions are a reason to review the plan with your diabetes team.
Lows after exercise
Lows can occur hours after a workout, including overnight. Follow your agreed monitoring and response plan during recovery. ADA exercise guidance discusses delayed lows.
Do not substitute cardio for prescribed insulin
Extra cardio cannot replace prescribed insulin or a pump-failure plan. If glucose is high with ketones, do not exercise; follow your ketone plan and obtain medical guidance. ADA explains why exercise can be unsafe in this situation.
Contact Enigma Nutrition for support
If you want help reviewing nutrition around your training, contact Enigma Nutrition.
See the T1D strength-training guide for the wider discussion.