Gender differences in the variables of exercise treadmill test in type 2 diabetes mellitus

Background: Exercise capacity, like some other variables of exercise stress test, is a strong predictor of cardiovascular and overall mortality. Many confounding factors, including gender, have been found to affect exercise capacity. This study evaluated whether exercise capacity differs in age-matched type 2 diabetic Nigerian men and their women counterparts and the hemodynamic variables of exercise treadmill test that correlate with exercise capacity in them. Materials and Methods: A total of 61 type 2 diabetics (male = 34; female = 27) aged 30 to 60 years who were recruited through the Medical Out-patient Department of OAUTHC, Ile Ife, Nigeria, underwent symptom- limited maximal treadmill exercise using Bruce protocol. Result: Patients had comparable clinical and demographic patterns. There was no gender difference in the chronotropic response to exercise. Males had faster heart rate recovery (HRR) than females. Though both sexes had similar resting systolic blood pressure (SBP), males had significantly higher peak SBP than females (216.2 ± 23.7 mmHg vs 203.3 ± 21.7 mmHg; P = 0.03). Exercise capacity was significantly higher in males (7.5 ± 2.0 METs) than females (6.4 ± 1.5 METs); P = 0.01. Significant correlates of exercise capacity in both sexes were fasting plasma glucose, resting diastolic blood pressure, Duke Treadmill Score, and HRR. Majority of the patients were in moderate DUKE risk subgroup and there was no statistically significant difference between males and females in this regard. Conclusion: Gender difference occurs in the exercise capacity of diabetic patients and the factors associated with this disparity may be related to gender differences in resting heart rate and HRR, both reflecting a withdrawal of vagal tone.