High intensity intermittent exercise improves cardiac structure and function and reduces liver fat in patients with type 2 diabetes: a randomised controlled trial.
OBJECTIVE
Cardiac disease remains the leading cause of mortality in type 2 diabetes, yet few strategies to target cardiac dysfunction have been developed. This randomised controlled trial aimed to investigate high intensity intermittent training (HIIT) as a potential therapy to improve cardiac structure and function in type 2 diabetes. The impact of HIIT on liver fat and metabolic control was also investigated.


METHODS
Using an online random allocation sequence, 28 patients with type 2 diabetes (metformin and diet controlled) were randomised to 12 weeks of HIIT (n = 14) or standard care (n = 14). Cardiac structure and function were measured by 3.0 T MRI and tagging. Liver fat was determined by 1H-magnetic resonance spectroscopy and glucose control by an OGTT. MRI analysis was performed by an observer blinded to group allocation. All study procedures took place in Newcastle upon Tyne, UK.


RESULTS
Five patients did not complete the study and were therefore excluded from analysis: this left 12 HIIT and 11 control patients for the intention-to-treat analysis. Compared with controls, HIIT improved cardiac structure (left ventricular wall mass 104 ± 17 g to 116 ± 20 g vs. 107 ± 25 g to 105 ± 25 g, p < 0.05) and systolic function (stroke volume 76 ± 16 ml to 87 ± 19 ml vs. 79 ± 14 ml to 75 ± 15 ml, p < 0.01). Early diastolic filling rates increased (241 ± 84 ml/s to 299 ± 89 ml/s vs. 250 ± 44 ml/s to 251 ± 47 ml/s, p < 0.05) and peak torsion decreased (8.1 ± 1.8° to 6.9 ± 1.6° vs. 7.1 ± 2.2° to 7.6 ± 1.9°, p < 0.05) in the treatment group. Following HIIT, there was a 39% relative reduction in liver fat (p < 0.05) and a reduction in HbA1c (7.1 ± 1.0% [54.5 mmol/mol] to 6.8 ± 0.9% [51.3 mmol/mol] vs. 7.2 ± 0.5% [54.9 mmol/mol] to 7.4 ± 0.7% [57.0 mmol/mol], p < 0.05). Changes in liver fat correlated with changes in HbA1c (r = 0.70, p < 0.000) and 2 h glucose (r = 0.57, p < 0.004). No adverse events were recorded.


CONCLUSIONS
This is the first study to demonstrate improvements in cardiac structure and function, along with the greatest reduction in liver fat, to be recorded following an exercise intervention in type 2 diabetes. HIIT should be considered by clinical care teams as a therapy to improve cardiometabolic risk in patients with type 2 diabetes.


BACKGROUND
www.isrctn.com 78698481 FUNDING: : Medical Research Council.
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|UKRC Centre for Ageing and Vitality, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
Sophie
S
Cassidy
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
Christian
C
Thoma
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|UKRC Centre for Ageing and Vitality, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
Kate
K
Hallsworth
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|Magnetic Resonance Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
Jehill
J
Parikh
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|Magnetic Resonance Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
Kieren G
KG
Hollingsworth
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|Magnetic Resonance Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
Roy
R
Taylor
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.|UKRC Centre for Ageing and Vitality, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
Djordje G
DG
Jakovljevic
Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK. michael.trenell@ncl.ac.uk.|Magnetic Resonance Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK. michael.trenell@ncl.ac.uk.|UKRC Centre for Ageing and Vitality, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK. michael.trenell@ncl.ac.uk.
Michael I
MI
Trenell
D000368:Aged; D001786:Blood Glucose / Q000737:chemistry; D002318:Cardiovascular Diseases / Q000150:complications / Q000628:therapy; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy / Q000628:therapy*; D003971:Diastole; D004032:Diet; D015444:Exercise; D005081:Exercise Therapy / Q000379:methods*; D005234:Fatty Liver / Q000473:pathology / Q000628:therapy*; D005260:Female; D005951:Glucose Tolerance Test; D006321:Heart / Q000502:physiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008687:Metformin / Q000627:therapeutic use; D008875:Middle Aged; D013599:Systole
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D008687:Metformin
Fatty liver; Heart diseases; Left ventricle; MRI; Type 2 diabetes mellitus