[Methods to identify the anaerobic threshold for type-2 diabetic and non-diabetic subjects]

In spite of Anaerobic Threshold (AT) to be widely used on exercise evaluation for different populations, there are few studies comparing methods to identify AT for individuals with type-2 diabetes.

To compare methods of AT determination on type-2 diabetics (T2D) and non-diabetic (ND) subjects and verify the acid-base balance as related to AT intensity.

T2D (n=10; 54.5+/-9.5 yr; 30.1+/-5.0 kg/m(2)) and younger ND (n=10; 36.6+/-12.8 yr; 23.9+/-5.0 kg/m(2)) performed an incremental test (IT) on a cycle ergometer. The over-proportional increase in VE/VO2 and blood lactate ([lac]) identified the ventilatory (VT) and lactate thresholds (LT) respectively. The workload corresponding to the lower blood glucose ([gluc]) during test identified the individual glucose threshold (IGT). The AT was also determined by polynomial adjustment of the VE/Workload and [lac]/Workload responses to identify exercise intensities above which an over-proportional increase in VE and [lac] did occur and were named VT VE/W and LT[lac]/W.

The workload (Watts-W) corresponding to LT, VT, IGT, LT Lac/W and VT VE/W of diabetics (85.0+/-32.1; 88.0+/-31.7; 86.0+/-33.8; 82.0+/-20.9 and 90.2+/-22.2W) and non-diabetics (139.0+/-39.0; 133.0+/-42.7; 140.8+/-36.4; 122.7+/-44.3 and 133.0+/-39.1W) differed between groups (p<0.001), but not within groups. Thus it was evidenced an agreement among the studied methods. The pH and pCO2 were significantly decreased in parallel to the increase in [lac], pO2 and VE at supra AT intensities.

The AT intensities, as determined by different methods both for diabetics and non-diabetic individuals, were in agreement to each other and identified exercise intensities above which the acid-basic balance is disrupted.