Cardiovagal modulation and efficacy of aerobic exercise training in obese individuals

Tracy Baynard, Styliani Goulopoulou, Ruth F. Sosnoff, Bo Fernhall, Jill A. Kanaley

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Type 2 diabetes (T2D) is associated with poor exercise tolerance and peak aerobic capacity (VO2peak) even when compared to obese nondiabetic peers. Exercise training studies have demonstrated improvements in VO 2peak 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 VO2peak 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% VO 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: VO 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 VO2peak was observed for the LCVM group. Changes in weight do not explain the change in VO2peak 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 VO2peak after a 16-wk aerobic training program.

Original languageEnglish
Pages (from-to)369-375
Number of pages7
JournalMedicine and Science in Sports and Exercise
Volume46
Issue number2
DOIs
StatePublished - Feb 2014

Keywords

  • AEROBIC CAPACITY
  • CARDIOVAGAL MODULATION
  • EXERCISE TRAINING
  • HR VARIABILITY
  • OBESITY
  • TYPE 2 DIABETES

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