Cardiovascular control during exercise in type 2 diabetes mellitus.

Simon Green,Mikel Egaña,Judith G. Regensteiner,Regis Lamberts,J. Chris Baldi

doi:10.1155/2015/654204

Abstract

Controlled studies of male and female subjects with type 2 diabetes mellitus (DM) of short duration (~3–5 years) show that DM reduces peak (L·min−1 and mL·kg−1·min−1) by an average of 12–15% and induces a greater slowing of the dynamic response of pulmonary during submaximal exercise. These effects occur in individuals less than 60 years of age but are reduced or absent in older males and are consistently associated with significant increases in the exercise pressor response despite normal resting blood pressure. This exaggerated pressor response, evidence of exertional hypertension in DM, is manifest during moderate submaximal exercise and coincides with a more constrained vasodilation in contracting muscles. Maximum vasodilation during contractions involving single muscle groups is reduced by DM, and the dynamic response of vasodilation during submaximal contractions is slowed. Such vascular constraint most likely contributes to exertional hypertension, impairs dynamic and peak responses, and reduces exercise tolerance. There is a need to establish the effect of DM on dynamic aspects of vascular control in skeletal muscle during whole-body exercise and to clarify contributions of altered cardiovascular control and increased arterial stiffness to exertional hypertension.

Highlights

Type 2 diabetes mellitus (DM) results in a loss of cardiorespiratory fitness and exercise tolerance and accentuates the blood pressure response during exercise
The gain of the heart rate (HR) or stroke volume (SV) responses was similar between DM and controls [11], suggesting that their contributions to the increase in cardiac output (CO) were not affected by DM. Recent evidence of these responses in adolescents suggests that the increases in SV and CO were blunted in DM [14]. Why this outcome differs from studies of adults is not clear, but we note that the resting blood pressure and Systemic Arterial Resistance (SAR) were ∼10% higher than normal in the adolescents with DM, whereas this has not usually been observed in adults
All three studies showed a significant increase in the time constant of the second phase of V O2 in middle-aged diabetic subjects compared with controls, but in all cases the initial rise and final value (240 s) of CO normalised to power output were not lower in DM subjects

Summary

Introduction

Type 2 diabetes mellitus (DM) results in a loss of cardiorespiratory fitness and exercise tolerance and accentuates the blood pressure response during exercise. Reviews have been written about exercise and cardiovascular function in DM [1, 2]. None of these reviews interpreted the available evidence within a context of cardiovascular control during exercise, and doing so provides a different insight into mechanisms underlying exercise intolerance and associated cardiovascular consequences of DM. We explore the interactions between cardiovascular responses and oxygen uptake (V O2) given the physiological relationships between them and the importance of V O2 to exercise tolerance, cardiorespiratory fitness, and mortality

Cardiovascular Control during Exercise

Effect of Diabetes on Cardiovascular

Mechanisms of Impaired Vascular Control in Diabetes

Synthesis

Findings

Future Directions