Skip Navigation LinksHome > June 2014 - Volume 46 - Issue 6 > Exercise Training Improves Heart Rate Variability after Meth...
Text sizing:
A
A
A
Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0000000000000201
Clinical Sciences

Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

DOLEZAL, BRETT ANDREW1; CHUDZYNSKI, JOY2; DICKERSON, DANIEL2; MOONEY, LARISSA2; RAWSON, RICHARD A.2; GARFINKEL, ALAN3; COOPER, CHRISTOPHER B.1

Collapse Box

Abstract

Purpose: Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent methamphetamine-dependent participants with age-matched, drug-free controls (DF) and also investigated whether HRV can be improved with exercise training in the methamphetamine-dependent participants.

Methods: In 50 participants (MD = 28; DF = 22), resting heart rate (HR; R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time domain (SDNN, RMSSD, pNN50) and frequency domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice-weekly exercise training (ME = 14) or equal attention without training (MC = 14) over 8 wk. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P ≤ 0.05.

Results: Participant characteristics were matched between groups (mean ± SD): age = 33 ± 6 yr; body mass = 82.7 ± 12 kg, body mass index = 26.8 ± 4.1 kg·min−2. Compared with DF, the MD group had significantly higher resting HR (P < 0.05), LFnu, and LF/HF (P < 0.001) as well as lower SDNN, RMSSD, pNN50, and HFnu (all P < 0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P < 0.001) increased SDNN (+14.7 ± 2.0 ms, +34%), RMSSD (+19.6 ± 4.2 ms, +63%), pNN50 (+22.6% ± 2.7%, +173%), HFnu (+14.2 ± 1.9, +60%), and decreased HR (−5.2 ± 1.1 bpm, −7%), LFnu (−9.6 ± 1.5, −16%), and LF/HF (−0.7 ± 0.3, −19%). These measures did not change from baseline in the MC group.

Conclusions: HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine-dependent individuals. Moreover, physical training yielded a marked increase in HRV, representing increased vagal modulation or improved autonomic balance.

© 2014 American College of Sports Medicine

Login

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.

Connect With Us