Usefulness of anaerobic threshold in estimating intensity of exercise for diabetics.

We examined the utility of the anaerobic threshold (AT) for quantifying the intensity of exercise that a diabetic patient is capable of handling. Thirteen diabetic patients treated with buformin exercised on a bicycle ergometer, and comparison was made with 20 healthy subjects matched for age and sex. The AT was determined from VO2 and VE with a personal computer. The intensity of exercise at the AT was 93 +/- 6 W in diabetic men and 80 +/- 10 W in diabetic women, values that were less than those of healthy subjects (P less than 0.05). There was a negative correlation between the intensity of exercise at the AT and the plasma concentration of buformin (P less than 0.01). There were no significant differences in either plasma lactic acid or pyruvic acid concentration at the AT between healthy subjects and diabetics. The plasma glucose at the AT or after exercise was lower than the baseline values in all subjects (P less than 0.01). The plasma insulin at the AT was lower than the baseline values in healthy subjects (P less than 0.01), but not in diabetics. There were no changes in plasma glucagon in any group. We concluded that determination of the AT is a simple, non-invasive procedure useful for ascertaining the optimal intensity of exercise for diabetics.