High-intensity interval exercise causes less blood sugar drop than moderate exercise in type 1 diabetes

Low confidence

some concerns bias

Last updated May 16, 2026

Key takeaway:

In a study of 7 trained men with type 1 diabetes, high-intensity interval exercise led to a smaller drop in blood glucose compared to moderate continuous exercise, with no hypoglycemia occurring in either exercise mode when insulin was adjusted appropriately.

Study at a glance

What was studied

Comparison of high-intensity interval versus continuous exercise on blood glucose and hormones in type 1 diabetes

Study type

Randomized Controlled Trials (RCTs)

duration

Short-Term (≤3 mo)

Intervention

High-intensity interval training (HIIT), Moderate continuous exercise (CON), Insulin degludec

Outcomes

Blood glucose, Blood lactate

Funding

Non-industry sponsored

Main effects

Blood glucose decrease ↓ (smaller in interval vs continuous exercise)

Hypoglycemia risk → (no events in either exercise mode)

Blood lactate ↑ (higher in intervals at low/moderate intensity)

Evidence Summary

Intervention	Outcome	Measured Change	Study Effect
High-intensity interval training (HIIT) (Physical Activity)	Blood glucose (Glycemic Control)	Decrease	Strong
High-intensity interval training (HIIT) (Physical Activity)	Blood lactate (Metabolic Health)	Increase	Strong
Insulin degludec (Medications)	Blood glucose (Glycemic Control)	Uncertain	Strong
Moderate continuous exercise (CON) (Physical Activity)	Blood glucose (Glycemic Control)	Decrease	Strong

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Evidence Suggest

High-intensity interval exercise with 20-second bursts causes less blood glucose decline than continuous exercise at matched average intensities
Both interval and continuous exercise can be performed safely without hypoglycemia when using ultra-long-acting insulin and reducing mealtime insulin based on exercise intensity
Hormone responses to exercise are similar between interval and continuous modes despite higher peak workloads in intervals

Who this applies to

This study examined trained men aged 18-35 years with type 1 diabetes for at least 12 months, good glycemic control (HbA1c <8%), no diabetic complications, and using intensified insulin therapy or insulin pumps. Results may not apply to women, older adults, sedentary individuals, or those with poor glycemic control or diabetic complications.

Keep in Mind

This is a very small pilot study in a highly specific population (young, trained males). The insulin adjustments and exercise protocols were highly controlled and may be difficult to implement outside research settings. Results apply specifically to ultra-long-acting insulin degludec and 20-second interval protocols. Individual responses to exercise vary considerably, and these group averages may not predict any individual's response. Anyone with diabetes should work with their healthcare team before making changes to insulin dosing around exercise.

Between the Lines

Very small sample size (only 7 participants)
Only trained males studied - not generalizable to women or sedentary individuals
Non-randomized exercise sequence may introduce bias
Highly controlled laboratory conditions may not reflect real-world exercise

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Journal Reference

Moser O, Tschakert G, Mueller A, et al. Effects of High-Intensity Interval Exercise versus Moderate Continuous Exercise on Glucose Homeostasis and Hormone Response in Patients with Type 1 Diabetes Mellitus Using Novel Ultra-Long-Acting Insulin. PLoS One. 2015;10(8):e0136489. doi:10.1371/journal.pone.0136489