Autonomic responses to physiological stressors in women with type 2 diabetes

Objective: To compare autonomic function, measured during handgrip (HG) and cold pressor (CP), between obese with and without type 2 diabetes and non-obese women in fasting and post-glucose load states. Methods: Twelve obese women with type 2 diabetes (50 ± 1 years), 15 obese women without type 2 diabetes (48 ± 2 years), and 12 non-obese women (49 ± 2 years) participated in this study. Heart rate variability (HRV) was determined during autonomic function tests, conducted in both the fasting state and after a glucose challenge (oral glucose tolerance test-OGTT). Results: Obese women with and without diabetes and non-obese women responded similarly fasted and post-glucose challenge, such that in the fasted state low frequency power normalized (LF(nu)) to total power (TP), log transformed (Ln) low frequency to high frequency ratio (LnLF/HF) and heart rate (HR) significantly increased with the autonomic functional tasks (P < 0.05), whereas HF(nu) significantly decreased with the tasks (P < 0.05). Handgrip elicited a lower LnTP and a higher HR (P < 0.05) when compared to CP in the fasted state. In the glucose challenged state LF(nu), LnLF/HF and HR increased (P < 0.05) and HF(nu) significantly decreased (P < 0.05). Interpretation: Results of autonomic testing did not differ between obese women, with and without diabetes, and non-obese women. The HG test elicited a greater reduction in HRV total power compared to the CP. This suggests that HG may be more useful when examining autonomic function in women with complicated diabetes.