Aims/hypothesisPancreatic fat accumulation may contribute to the development of beta cell dysfunction. Exercise training improves whole-body insulin sensitivity, but its effects on pancreatic fat content and beta cell dysfunction are unclear. The aim of this parallel-group randomised controlled trial was to evaluate the effects of exercise training on pancreatic fat and beta cell function in healthy and prediabetic or type 2 diabetic participants and to test whether the responses were similar regardless of baseline glucose tolerance.MethodsUsing newspaper announcements, a total of 97 sedentary 40–55-year-old individuals were assessed for eligibility. Prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and type 2 diabetes were defined by ADA criteria. Of the screened candidates, 28 healthy men and 26 prediabetic or type 2 diabetic men and women met the inclusion criteria and were randomised into 2-week-long sprint interval or moderate-intensity continuous training programmes in a 1:1 allocation ratio using random permuted blocks. The primary outcome was pancreatic fat, which was measured by magnetic resonance spectroscopy. As secondary outcomes, beta cell function was studied using variables derived from OGTT, and whole-body insulin sensitivity and pancreatic fatty acid and glucose uptake were measured using positron emission tomography. The measurements were carried out at the Turku PET Centre, Finland. The analyses were based on an intention-to-treat principle. Given the nature of the intervention, blinding was not applicable.ResultsAt baseline, the group of prediabetic or type 2 diabetic men had a higher pancreatic fat content and impaired beta cell function compared with the healthy men, while glucose and fatty acid uptake into the pancreas was similar. Exercise training decreased pancreatic fat 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). In prediabetic or type 2 diabetic men and women, both exercise modes similarly improved variables describing beta cell function.Conclusions/interpretationTwo weeks of exercise training improves beta cell function in prediabetic or type 2 diabetic individuals and decreases pancreatic fat regardless of baseline glucose tolerance. This study shows that short-term training efficiently reduces ectopic fat within the pancreas, and exercise training may therefore reduce the risk of type 2 diabetes.Trial registrationClinicalTrials.gov NCT01344928FundingThis study was funded by the Emil Aaltonen Foundation, the European Foundation for the Study of Diabetes, the Finnish Diabetes Foundation, the Orion Research Foundation, the Academy of Finland (grants 251399, 256470, 281440, and 283319), the Ministry of Education of the State of Finland, the Paavo Nurmi Foundation, the ...

The purpose of this study was to get reliable insight into injury risk in various commuting and lifestyle activities, as well as recreational and competitive sports. A cohort of 3 657 persons was randomly selected from the 15- to 74-year-old Finnish population. Ninety-two percent (n = 3 363) of the subjects accepted to participate the one-year follow-up, record all their physical activities that lasted 15 min or more, and register all acute and overuse injuries that occurred during these activities. To collect the information, the study subjects were interviewed by phone by the trained personnel of the Statistics Finland three times in four-month intervals. The individual injury risk per exposure time was relatively low, ranging from 0.19 to 1.5 per 1 000 hours of participation, in commuting and lifestyle activities including walking and cycling to work, gardening, home repair, hunting and fishing, and, in sports such as golf, dancing, swimming, walking, and rowing. The risk was clearly higher in squash, orienteering, and contact and team sports, such as judo, wrestling, karate, rinkball, floorball, basketball, soccer, ice hockey, volleyball, and Finnish baseball ranging from 6.6 to 18.3 per 1 000 hours of participation. However, the highest absolute number of injuries occurred in low-risk activities, such as gardening, walking, home-repair, and cycling, because they are performed so often. In conclusion, individual injury risk per exposure hours is relatively low in commuting and lifestyle activities compared to many recreational and competitive sports. However, at a population level, these low-to-moderate intensity activities are widely practised producing a rather high absolute number of injuries, and thus, preventive efforts are needed in these activities, too.

High-intensity interval training (HIIT) is a time-efficient way of obtaining the health benefits of exercise, although the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n = 14 in both) and underwent six cycle ergometer training sessions within 2 weeks (HIIT session: 4-6 × 30 s all-out cycling/4 min recovery, MICT session 40-60 min at 60% V̇O2 peak ). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography was used to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, although no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU was decreased by training (HIIT from 46.5 to 35.9; MICT from 47.4 to 44.4 mmol 100 g min , P = 0.007 for time, P = 0.11 for group × time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P = 0.03 for group × time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects.