Medicine & Science in Sports & Exercise, it found that the more you exercise, the higher the body's resistance to insulin and the onset of Type 2 diabetes. What’s significant is that there didn’t appear to be a limit to the benefit per time spent exercising; that is, some exercise was good, more was better and the protective benefit didn’t seem to have a ceiling.
Researchers had subjects work out at least three times a week for 16 weeks. Some worked out more. Everyone did at least three aerobic sessions a week at 75 percent of max heart rate for 45 minutes (in running terms, faster than easy running, a bit slower than lactate threshold pace). The researchers combined the subjects’ frequency, intensity and duration to get what they termed “exercise dose.”
Based on the results, the researchers concluded:
Improved insulin sensitivity was significantly related to exercise dose in a graded dose–response relationship. No evidence of threshold or maximal dose–response effect was observed. Age and gender did not influence this dose–response relationship. Exercise intensity was also significantly related to improvements in insulin sensitivity.