Lifting weights can significantly reduce the risk of diabetes in men, a study has found.
Regular weight training cut the chances of developing the most common form of the disease by up to 34%.
Adding aerobic exercise, such as brisk walking or running, can lead to even greater benefits, the research showed.
Scientists analysed data on 32,000 Americans taking part in the Health Professionals Follow-Up Study, which looked at lifestyle effects on health.
Information on how much time the men spent working out in gyms and taking aerobic exercise was collected from questionnaires.
During the study period from 1990 to 2008, a total of 2,278 participants developed Type 2 diabetes.
The findings showed that even modest amounts of weight training may reduce diabetes risk.
Participants were categorised according to whether they did between one and 59 minutes, 60 and 149 minutes, or at least 150 minutes of weight training a week.
Pushing iron reduced diabetes risk by 12%, 25% and 34% respectively, compared with no training.
The most active men who did more than 150 minutes of aerobics as well as at least 150 minutes of weight training per week cut their risk by 59%.
Lead scientist Anders Grontved from the University of Southern Denmark, who is seconded to Harvard University in the US, said: "Until now, previous studies have reported that aerobic exercise is of major importance for Type 2 diabetes prevention. But many people have difficulty engaging in or adhering to aerobic exercise. These new results suggest that weight training, to a large extent, can serve as an alternative to aerobic exercise for Type 2 diabetes prevention."
Type 2 diabetes, which is closely linked to obesity and lifestyle, occurs when the body stops responding to the blood sugar regulating hormone insulin.
An estimated 346 million people worldwide have the disease. The number of diabetes-related deaths is expected to double between 2005 and 2030, according to the World Health Organisation (WHO).
More than two million people are diagnosed with Type 2 diabetes in the UK. About a million more are thought to have the disease without knowing it.
The new findings are published in the latest online issue of the journal Archives of Internal Medicine.
Co-author Professor Frank Hu, a nutrition expert from the Harvard School of Public Health, said: "This study provides clear evidence that weight training has beneficial effects on diabetes risk over and above aerobic exercise, which are likely to be mediated through increased muscle mass and improved insulin sensitivity.
"To achieve the best results for diabetes prevention, resistance training can be incorporated with aerobic exercise."
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