Related Experiment Video
Updated: May 9, 2026
A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats
Published on: April 28, 2023
Cardiovagal modulation and efficacy of aerobic exercise training in obese individuals
Tracy Baynard1, Styliani Goulopoulou, Ruth F Sosnoff
11Integrative Physiology Laboratory, Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL; 2Department of Physiology, Georgia Regents University, Augusta, GA; 3Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL; and 4Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO.
Unlabelled:
Type 2 diabetes (T2D) is associated with poor exercise tolerance and peak aerobic capacity (V˙O2peak) even when compared to obese nondiabetic peers. Exercise training studies have demonstrated improvements in V˙O2peak among patients with T2D, yet there is a large amount of variability in this response. Recent evidence suggests that cardiac autonomic modulation may be an important factor when considering improvements in aerobic capacity.
Purpose:
This study aimed to determine the effects of a 16-wk aerobic exercise program on V˙O2peak in obese individuals, with and without T2D, who were classified as having either high or low cardiovagal modulation (HCVM or LCVM) at baseline.
Methods:
Obese individuals (38 women and 19 men; body mass index = 36.1 kg·m(-2)) were studied in the fasted state. ECG recordings were obtained while seated for 3 min, before and after 4 months of exercise training (4 d·wk(-1), 65% V˙O(2peak)). The ECG recording was analyzed for HR variability in the spectral domain. Groups were split on a marker of CVM (normalized high frequency (HFnu)) at the 50th percentile, as either HCVM or LCVM.
Results:
V˙O(2peak) only increased with exercise training among those classified as having HCVM, regardless of diabetes status (T2D: HCVM = 20.3-22.5 mL·kg(-1)min(-1), LCVM = 24.3-25.0 mL·kg(-1)min(-1); obese nondiabetics: HCVM = 24.5-26.3 mL·kg(-1)min(-1), LCVM = 23.1-23.7 mL·kg(-1)min(-1)) (P < 0.05). No change in V˙O(2peak) was observed for the LCVM group. Changes in weight do not explain the change in V˙O(2peak) among the HCVM group. Glucose tolerance only improved among the LCVM group with T2D.
Conclusions:
Obese individuals, with or without T2D, when classified as having relatively HCVM before exercise training, have a greater propensity to improve V˙O(2peak) after a 16-wk aerobic training program.
Related Concept Videos
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:17Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
01:31Regulation of Heart Rates
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:20Pharmacokinetics in Obese Patients: Drug Metabolism and Excretion
01:29Pathophysiology of Cardiac Performance