Heiskanen MA, et al. - The effects of exercise training on pancreatic fat and beta cell function were investigated in healthy and prediabetic or type 2 diabetic participants. Additionally, they evaluated whether the responses were similar irrespective of baseline glucose tolerance. An improvement was seen in the beta cell function in prediabetic or type 2 diabetic individuals after 2 weeks of exercise training. It also decreased pancreatic fat, irrespective of baseline glucose tolerance. Ultimately, ectopic fat within the pancreas was reduced with short-term training, consequently the risk of type 2 diabetes may be reduced by exercise training.

Methods

• A total of 97 sedentary 40-55-year-old individuals were investigated for eligibility.
• For this study, prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and type 2 diabetes were defined by ADA criteria.
• Among those screened, 28 healthy men and 26 prediabetic or type 2 diabetic men and women met inclusion criteria.
• Enrollees were randomized into 2-week-long sprint interval or moderate-intensity continuous training programs in a 1:1 allocation ratio via random permuted blocks.
• Pancreatic fat, measured by magnetic resonance spectroscopy, was the primary outcome.
• Examination of beta cell function using variables derived from OGTT and whole-body insulin sensitivity and pancreatic fatty acid and glucose uptake via positron emission tomography served as the secondary outcome.
• The measurements were performed at the Turku PET Centre, Finland.
• The analyses were based on an intention-to-treat principle.
• Blinding was not applicable due to the nature of the intervention.

Results

• Results depicted that the group of prediabetic or type 2 diabetic men presented with a higher pancreatic fat content and impaired beta cell function than healthy men.
• Glucose and fatty acid uptake into the pancreas appeared to be similar at baseline.
• Through exercise training, the pancreatic fat decreased similarly in healthy (from 4.4% [3.0%, 6.1%] to 3.6% [2.4%, 5.2%] [mean, 95% CI]) and prediabetic or type 2 diabetic men (from 8.7% [6.0%, 11.9%] to 6.7% [4.4%, 9.6%]; p=0.036 for time effect) without any changes in pancreatic substrate uptake (p ≥ 0.31 for time effect in both insulin-stimulated glucose and fasting state fatty acid uptake).
• Both exercise modes produced similar improvement of the variables describing beta cell function in prediabetic or type 2 diabetic men and women.