Abstract
Aims/hypothesis
Exercise is recommended for the treatment and prevention of type 2 diabetes. However, the most effective time of day to achieve beneficial effects on health remains unknown. We aimed to determine whether exercise training at two distinct times of day would have differing effects on 24 h blood glucose levels in men with type 2 diabetes.
Methods
Eleven men with type 2 diabetes underwent a randomised crossover trial. Inclusion criteria were 45–68 years of age and BMI between 23 and 33 kg/m2. Exclusion criteria were insulin treatment and presence of another systemic illness. Researchers were not blinded to the group assignment. The trial involved 2 weeks of either morning or afternoon high-intensity interval training (HIIT) (three sessions/week), followed by a 2 week wash-out period and a subsequent period of the opposite training regimen. Continuous glucose monitor (CGM)-based data were obtained.
Results
Morning HIIT increased CGM-based glucose concentration (6.9 ± 0.4 mmol/l; mean ± SEM for the exercise days during week 1) compared with either the pre-training period (6.4 ± 0.3 mmol/l) or afternoon HIIT (6.2 ± 0.3 mmol/l for the exercise days during week 1). Conversely, afternoon HIIT reduced the CGM-based glucose concentration compared with either the pre-training period or morning HIIT. Afternoon HIIT was associated with elevated thyroid-stimulating hormone (TSH; 1.9 ± 0.2 mU/l) and reduced T4 (15.8 ± 0.7 pmol/l) concentrations compared with pre-training (1.4 ± 0.2 mU/l for TSH; 16.8 ± 0.6 pmol/l for T4). TSH was also elevated after morning HIIT (1.7 ± 0.2 mU/l), whereas T4 concentrations were unaltered.
Conclusions/interpretation
Afternoon HIIT was more efficacious than morning HIIT at improving blood glucose in men with type 2 diabetes. Strikingly, morning HIIT had an acute, deleterious effect, increasing blood glucose. However, studies of longer training regimens are warranted to establish the persistence of this adverse effect. Our data highlight the importance of optimising the timing of exercise when prescribing it as treatment for type 2 diabetes.
Exercise is recommended for the treatment and prevention of type 2 diabetes. However, the most effective time of day to achieve beneficial effects on health remains unknown. We aimed to determine whether exercise training at two distinct times of day would have differing effects on 24 h blood glucose levels in men with type 2 diabetes.
Methods
Eleven men with type 2 diabetes underwent a randomised crossover trial. Inclusion criteria were 45–68 years of age and BMI between 23 and 33 kg/m2. Exclusion criteria were insulin treatment and presence of another systemic illness. Researchers were not blinded to the group assignment. The trial involved 2 weeks of either morning or afternoon high-intensity interval training (HIIT) (three sessions/week), followed by a 2 week wash-out period and a subsequent period of the opposite training regimen. Continuous glucose monitor (CGM)-based data were obtained.
Results
Morning HIIT increased CGM-based glucose concentration (6.9 ± 0.4 mmol/l; mean ± SEM for the exercise days during week 1) compared with either the pre-training period (6.4 ± 0.3 mmol/l) or afternoon HIIT (6.2 ± 0.3 mmol/l for the exercise days during week 1). Conversely, afternoon HIIT reduced the CGM-based glucose concentration compared with either the pre-training period or morning HIIT. Afternoon HIIT was associated with elevated thyroid-stimulating hormone (TSH; 1.9 ± 0.2 mU/l) and reduced T4 (15.8 ± 0.7 pmol/l) concentrations compared with pre-training (1.4 ± 0.2 mU/l for TSH; 16.8 ± 0.6 pmol/l for T4). TSH was also elevated after morning HIIT (1.7 ± 0.2 mU/l), whereas T4 concentrations were unaltered.
Conclusions/interpretation
Afternoon HIIT was more efficacious than morning HIIT at improving blood glucose in men with type 2 diabetes. Strikingly, morning HIIT had an acute, deleterious effect, increasing blood glucose. However, studies of longer training regimens are warranted to establish the persistence of this adverse effect. Our data highlight the importance of optimising the timing of exercise when prescribing it as treatment for type 2 diabetes.
| Original language | English |
|---|---|
| Pages (from-to) | 233-237 |
| Number of pages | 5 |
| Journal | Diabetologia |
| Volume | 62 |
| Early online date | 13 Nov 2018 |
| DOIs | |
| Publication status | Published - Feb 2019 |
Bibliographical note
Data availabilityThe data analysed during the current study are available from the corresponding author on reasonable request.
Funding
The authors are supported by grants from Novo Nordisk Foundation (NNF14OC0011493 and NNF14OC0009941), Swedish Diabetes Foundation (DIA2015-052), Wenner-Gren Foundation, Swedish Research Council (2015-00165), Strategic Research Program in Diabetes at Karolinska Institutet (2009-1068), Stockholm County Council (SLL20150517 and SLL20170159) and Swedish Heart Lung Foundation (20150423).
Keywords
- Blood glucose level
- circadian rhythm
- Continuous glucose monitoring
- exercise
- High-intensity interval training
- Type 2 diabetes
Access to Document
- Savikj_etal_Diabet_AfternoonExerciseIsMoreEfficac_VOR
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Brendan Gabriel
- School of Medicine, Medical Sciences & Nutrition, The Rowett Institute of Nutrition and Health - Research Fellow
- School of Medicine, Medical Sciences & Nutrition, Aberdeen Cardiovascular and Diabetes Centre
Person: Academic Related - Research