Systolic and Diastolic Abnormalities Reduce the Cardiac Response to Exercise in Adolescents With Type 2 Diabetes

Abstract

OBJECTIVETo better understand the cardiac limitations during exercise in adolescents with type 2 diabetes mellitus (T2DM), we measured left ventricular performance with magnetic resonance imaging (MRI) during exercise in diabetic and nondiabetic adolescents. RESEARCH DESIGN AND METHODSThirteen subjects with T2DM, 27 overweight/obese nondiabetic (ObeseND) subjects, and 19 nondiabetic nonobese control subjects were recruited. Cardiac (left ventricular) MRI scans were performed at rest and during submaximal exercise. RESULTSVO 2 peak indexed to fat-free mass was reduced in T2DM and ObeseND subjects compared with control subjects (P < 0.0001). Indexed cardiac output increased less during exercise and was 20% lower in T2DM subjects due to reduced stroke volume. This was a consequence of reduced ventricular filling with smaller enddiastolic volume, which decreased further during exercise in T2DM subjects, but not in ObeseND or control subjects. End-systolic volume was also smaller in T2DM subjects. These changes were associated with increased resting and exercise diastolic blood pressure, and total peripheral resistance in T2DM subjects. CONCLUSIONSIndependently of obesity, T2DM impairs cardiac function during exercise in adolescents. Diabetes Care 2014;37:143937: -144637: | DOI: 10.233737: /dc13-2031 Exercise is a standard recommendation in the management and prevention of type 2 diabetes mellitus (T2DM) (1,2). Regrettably, people with diabetes often have reduced cardiac reserve (3,4) and a resultant decrease in aerobic capacity (3,5). Adults with T2DM have smaller left ventricular stroke volume (6) and reduced heart rates (3,7) during peak exercise. These factors may present a barrier to exercise participation because recommended "moderate intensity" exercise (2) requires a greater proportion of their aerobic capacity (8).Several authors suggest that reduced early left ventricular diastolic filling (i.e., diastolic dysfunction) is responsible for lower aerobic capacity in people with T2DM,

Obesity alters molecular and functional cardiac responses to ischemia/reperfusion and glucagon-like peptide-1 receptor agonism

“…In particular, under normal baseline conditions obesity tended to produce a leftward shift of the left ventricular pressure-volume relationship relative to lean swine (Figure 1, panels A and C solid lines). Such reductions in end-diastolic filling volumes with similar systolic pressure generation have been previously observed in animal models[47] and in obese humans[48]. These changes are likely attributable in part to augmented sympathetic tone, which is well documented in the setting of obesity [28, 31, 66].…”

Cardiovascular consequences of metabolic syndrome

“…(55) Importantly, cardiac functional responses to physiologic perturbations (e.g. exercise),(56-58) pathologic conditions (e.g. myocardial ischemia)(59-61), or pharmacologic stimuli (e.g.…”

Cardiac Autonomic Modulation and the Kinetics of Heart Rate Responses in the On- and Off-Transient during Exercise in Women with Metabolic Syndrome

“…Abnormalities in cardiovascular and metabolic off-transient have been reported in coronary heart disease (Spies et al, 2005), obesity/overweight (Franco et al, 2015; Tomlinson et al, 2015), diabetes (Baldi et al, 2016), aging (Simões et al, 2013), and have been consistently related to cardiovascular risk and increased mortality (Cole et al, 2000; Nishime et al, 2000; Watanabe et al, 2001; Javorka et al, 2003). The higher resting heart rate (HR) in people with insulin resistance (Baldi et al, 2016) is supposed to be a compensatory mechanism adopted to maintain cardiac output in face of a lower stroke volume (Gusso et al, 2008; Pinto et al, 2014). Although MS shares many clinical symptoms with diabetes, it is not known whether such alterations are also found in MS.…”

“…The increase in HR in response to exercise is attenuated in diabetes (Gusso et al, 2008; Pinto et al, 2014; Baldi et al, 2016), which contrasts with the elevated sympathetic and attenuated parasympathetic activity and suggests that the autonomic modulation during exercise might be different from rest. Whilst the off-transient is commonly studied in different populations, the on-transient might also be an important parameter as this reflects the cardiac adjustments adopted to supply the energy demands of the working muscles (Rowell and O'Leary, 1990).…”