Lactate and ventilatory thresholds in type 2 diabetic women

Anaerobic threshold (AT) has been considered the optimal exercise intensity for type 2 diabetes mellitus (DM 2) patients, but there is little information about the comparison between lactate (LT) and ventilatory (VT) thresholds in this population, particularly during treadmill exercise. Therefore, we evaluated DM 2 women in order to compare and analyze the relationships between VT and LT intensities. Fifteen women with DM 2 without complications and comorbidities (50.7 +/- 8.0 years; 71.3 +/- 8.6 kg; 154 5 cm; 37.8 +/- 3.9% fat; 4.7 +/- 3.2 years of disease diagnose and 138 +/- 45 mg/dl fasting glucose) were subjected to a graded treadmill test-initial velocity and increments of 1 km/h every 2 min until voluntary exhaustion. VT was determined from V-E/V-O2 and V-E - V-CO2 ratios and LT was defined as the point at which a first increase in blood lactate occurs during incremental test. Our results showed no significant differences (p > 0.05) and significant correlations between VT and LT expressed in velocity (4.7 +/- 0.7 versus 4.6 +/- 0.7 km/h, r = 0.62), absolute V-O2 (1.27 +/- 0.33 versus 1.24 +/- 0.281 min(-1), r = 0.93); relative V-O2, (18.3 +/- 5.7 versus 17.6 +/- 4.6 ml kg(-1) min(-1) r = 0.84) and %V-O2max (80 +/- 12 versus 78 +/- 10%, r = 0.82). These results suggest that both VT and LT can be used to access AT in DM 2 women during graded treadmill exercise. (c) 2006 Elsevier Ireland Ltd. All rights reserved.