Metabolic responses to hyperglycaemia during exercise in elderly men

  The present study was designed to determine the metabolic responses to hyperglycaemia during exercise in elderly men. Eight healthy males (Age, 63.3±5.2 years) voluntarily participated and reported to the physiology laboratory on two separate occasions. With one week intervening subjects performed 40 min exercise on a cycle ergometer at 60% VO2max after 30 minutes of ‘prime’ glucose or placebo infusion. Respiratory gases were undertaken throughout the exercise and four blood samples were taken before infusion, after 30 min infusion, after 20 min exercise and immediately after exercise. Blood samples were analyzed to determine insulin, NEFA, glycerol, 3- OHB and HOMA Scores. Fat and carbohydrate oxidation were calculated by using respiratory gases of O2 and CO2. Insulin and glucose concentrations were significantly (p<0.05) higher, and NEFA and glycerol were lower during exercise after glucose infusion. However, 3-OHB, fat and carbohydrate oxidations were not significantly different between two trials (p>0.05). Based on the findings of the present study it could be concluded that in elderly men the maintenance of blood glucose during exercise through glucose infusion affects on lipolysis and metabolic factors, but has no effect on muscular fat and carbohydrate oxidation.