Proceedings of The Physiological Society
University of Oxford (2011) Proc Physiol Soc 23, PC208
Similar cardiovascular and metabolic adaptations to exercise training in older men and women with type 2 diabetes
E. O'Connor1, C. Kiely1, D. O'Shea2, S. Green3, M. Egana1
1. Physiology, Trinity College Dublin, Dublin, Ireland. 2. Endocrinology, St. Columcille's Hospital, Dublin, Ireland. 3. Physiology, University of Otago, Dunedin, New Zealand.
Improvements in peak oxygen uptake (VO2peak) following exercise training in healthy older individuals are not sex-specific. However, studies suggest greater levels of cardiovascular adaptations occur in males, with a greater level of O2 extraction in females1. This human study examined if cardiovascular and metabolic adaptations to exercise training were sex-specific in individuals with type 2 diabetes (T2D). 25 male (M) (EXS n=13; CTL n=12) & 19 female (F) (EXS=10; CTL=9) age- and BMI-matched individuals with T2D completed testing. The exercise groups were aerobically & resistance trained three times per week for 12 weeks. Before and after the intervention, subjects underwent a graded incremental cycle test to assess ventilatory threshold (VT) and VO2peak. VO2 kinetic responses to steady-state cycling at 80% of their current ventilatory threshold (VT) were determined by fitting a bi-exponential function to the VO2 data. Cardiac Output (inert gas rebreathing) (CO) was assessed at rest, 30 seconds and 4 minutes. Data were analysed using a 3-way repeated measures ANOVA, with significant differences detected using the Bonferroni post hoc test. Exercise resulted in a significant improvement (P<0.05) in VO2peak (EXS M: (mean ± sd) 26.8 ± 4.2 vs. 29.5 ± 4.1; EXS F: 19.8 ± 5.3 vs. 22.9 ± 4.7ml.kg-1.min-1). The magnitude of increase in VO2max (EXS M: 10.61%; EXS F: 16.91%) was similar between groups. Training resulted in a trend towards faster time constant values for the 2nd phase of the VO2 kinetic response (P = 0.095). Males demonstrated higher CO and stroke volumes (SV) than females at all time points, but exercising males and females did not show any significant improvements in cardiovascular parameters following the intervention compared to baseline (table 1). The control groups did not demonstrate any significant differences. Consistent with healthy individuals, peak performance improved by a similar magnitude in males and females with T2D following the training intervention. However, the lack of gender specific differences in VO2 kinetic, CO and SV responses during steady-state exercise suggest that the improvement in performance in males and females following training was driven by a similar level of cardiovascular adaptations, differing from findings in non-diabetic individuals.
Where applicable, experiments conform with Society ethical requirements