The influence of high-resistance training on glucose tolerance in young and elderly subjects

Aging is associated with a decrease in glucose tolerance. In younger subjects both high and low intensity forms of exercise have been shown to improve glucose tolerance. The purpose of this investigation was to determine whether or not strength training in elderly subjects would have a positive effect upon glucose and insulin responsiveness following a glucose feeding. The medical history of each subject and an exercise stress test were given prior to the establishment of the two age groups: those individuals with contra-indications for exercise were not tested further. An oral glucose tolerance test, 100 g, was administered to six young (23 +/- 1 year) and 9 elderly (63 +/- 1 year) male subjects before and after 12 weeks of a supervised progressive resistance weight lifting program, which employed Nautilus equipment. All the major muscle groups of the body were exercised and a three set, six-eight repetition, training protocol was followed. Blood samples were taken at 0, 30, 60, 120 and 180 min; after centrifugation (1169 g for 15 min) the serum was frozen for analysis of glucose and insulin. Percent body fat was determined by skin calipers and the Lean Body Mass estimated. The 6 Rep max for the leg press, leg extension and bench press machines were used to determine the strength gains made for the 12 weeks of training. The results show that both the young and elderly subjects had a significant increase (P less than 0.05) in LBM and a significant decrease (P less than 0.05) in percent body fat with training. In the young these changes occurred without a significant change in body weight, whereas the elderly had a significant increase (P less than 0.05) in body weight. In terms of strength, both the young and elderly showed significant gains (P less than 0.05) following training. The training protocol had little effect on the glucose response, but did significantly lower (P less than 0.05) the plasma insulin response to a glucose load. In response to a 100 g oral glucose load insulin declined regardless of age, with the insulin sum of the young and elderly being, 31.8% and 32.6% lower, respectively, after training. Although strength training improved glucose tolerance in both age groups, the response of the elderly subjects was well below that of the young. In conclusion, the data present here demonstrate that 12 weeks of high resistance strength training improved the overall physical fitness level of both the young and elderly participants of this study, but did not affect age related differences.