The Study
A Comparison of the Effects of the Timing of Resistance Exercise on Glucose Levels Within the Target Range in People With Type 1 Diabetes (TREX Study): A Randomized Crossover Trial
This study is like a fair test where people with type 1 diabetes tried three different ways of exercising and researchers measured their blood sugar each time. Because they switched around the order randomly, we can say that one way probably caused better blood sugar results — but only for the short time right after exercise.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested whether doing weightlifting in the morning without eating, or in the afternoon after eating, affects blood sugar levels in people with type 1 diabetes.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 569 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The difference in high blood sugar time (18.1%) is big enough to increase long-term health risks — so for MDI users, eating before morning workouts or doing them in the afternoon helps.
- 2When people used insulin injections (MDI), lifting weights in the morning without eating raised blood sugar more than lifting in the afternoon after eating: average glucose was 9.6 vs.
- 38.4 mmol/L, and high blood sugar lasted 44% vs.
- 426% of the time.
- 5When using insulin pumps, timing and eating didn’t matter.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Diabetes/Metabolism Research and Reviews
Year
2026
Authors
E. A. Ozairi, Yasmine Hamdan, Ameenah A Al Awadhi, Nourah B Al Otaibi, A. Baqer, Daniel J. West, Dennis Taliping, J. Kandari, Stuart R Gray
Related Content
Claims (6)
In adults with type 1 diabetes who use multiple daily insulin injections, resistance exercise done in the morning while fasting leads to higher blood glucose levels and more time spent with blood glucose above 10.0 mmol/L over the next six hours than the same exercise done in the afternoon after eating.
In adults with type 1 diabetes using multiple daily insulin injections, afternoon resistance exercise after eating causes a larger increase in blood glucose levels over time compared to morning resistance exercise on an empty stomach, and this difference is larger than the level linked to higher risk of small blood vessel damage.
For adults with type 1 diabetes using insulin pumps, the timing of food intake before resistance exercise—whether fasted in the morning or fed in the afternoon—does not change glucose levels or time in target range during the six hours after exercise.
When muscles contract, they pull glucose from the blood into muscle cells without needing insulin, by moving GLUT4 transporters to the cell surface.
In adults with type 1 diabetes, exercising in the morning or afternoon does not change blood glucose levels after exercise when meals are controlled.
In adults with type 1 diabetes, doing resistance exercise in the morning while fasting, in the morning after eating, or in the afternoon after eating has no meaningful effect on blood glucose levels during the night.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.