The effect of acute aerobic exercise on central arterial stiffness,wave reflections,and hemodynamics in adults with diabetes:A randomized cross-over design

Background:Individuals with diabetes have greater central arterial stiffness,wave reflections,and hemodynamics,all of which promote the accelerated cardiovascular pathology seen in this population.Acute aerobic exercise has been shown to be an effective strategy for reducing central arterial stiffness,wave reflections,and hemodynamics in healthy individuals;however,the effects of acute aerobic exercise in reducing these outcomes is not well established in people with diabetes.Recently,implementation of high-intensity interval exercise(HIIE)has shown superior improvements in cardiovascular health outcomes when compared to traditional aerobic exercise.Yet,the effect of HIIE on the aforementioned outcomes in people with diabetes is not known.The purpose of this study was to(i)describe the central arterial stiffness,wave reflections,and hemodynamic responses to a bout of HIIE and moderate-intensity continuous exercise(MICE)in adults with diabetes;and(ii)compare the effects of HIIE and MICE on the aforementioned outcomes.Methods:A total of 24 adult men and women(aged 29-59 years old)with type 1(n=12)and type 2(n=12)diabetes participated in a randomized cross-over study.All participants completed the following protocols:(i)HIIE:cycling for 4×4 min at 85%-95%of heart rate peak(HR_(peak)),interspersed with 3 min of active recovery at 60%-70%HR_(peak);(ii)MICE:33 min of continuous cycling at 60%-70%HR_(peak);and(iii)control(CON):lying quietly in a supine position for 30 min.Results:A significant group￡time effect was found for changes in central systolic blood pressure(F=3.20,p=0.01)with a transient reduction for the HIIE group but not for the MICE or CON groups.There was a significant group￡time effect for changes in augmentation index at a heart rate of 75 beats/min(F=2.32,p=0.04)with a decrease following for HIIE and MICE but not for CON.For all other measures of central arterial stiffness and hemodynamics,no significant changes were observed(p>0.05).Conclusion:A bout of HIIE appears to lead to a greater transient reduction in central systolic blood pressure than the reduction observed following MICE;however,both HIIE and MICE improved augmentation index at a heart rate of 75 beats/min in people with diabetes.There was no significant difference in response to HIIE and MICE in all outcomes.This provides preliminary evidence on the role of HIIE on such outcomes in people with diabetes.

Oxygen uptake response to switching stairs exercise by non-parametric modeling

Oxygen uptake plays a crucial role in the evaluation of endurance performance during exercise and is extensively utilized for metabolic assessment. This study records the oxygen uptake during the exercise phase (i.e., ascending or descending) of the stair exercise, utilizing an experimental dataset that includes ten participants and covers various exercise periods. Based on the designed experiment protocol, a non-parametric modeling method with kernel-based regularization is generally applied to estimate the oxygen uptake changes during the switching stairs exercise, which closely resembles daily life activities. The modeling results indicate the effectiveness of the non-parametric modeling approach when compared to fixed-order models in terms of accuracy, stability, and compatibility. The influence of exercise duration on estimated fitness reveals that the model of the phase-oxygen uptake system is not time-invariant related to respiratory metabolism regulation and muscle fatigue. Consequently, it allows us to study the humans’ conversion mechanism at different metabolic rates and facilitates the standardization and development of exercise prescriptions.