Breathe & Beat: The Effect Of Aerobic Exercise On Cardiac Autonomic Function In Cigarette Smokers - A Systematic Review And Meta-Analysi

Abstract

Background: Cigarette smoking is found to be an important marker and reason for depressed parasympathetic activity and elevated sympathovagal imbalance. Whether structured aerobic training can reverse this autonomic pattern in smokers who continue to smoke has clinical relevance.

Objective: To evaluate the effect of aerobic exercise training on cardiac autonomic function in adult cigarette smokers.
Data sources: PubMed/Medline, PubMed Central (PMC), MDPI, Wiley Online Library

Eligibility: Randomized or non-randomized controlled trials in adult cigarette smokers testing ≥4 weeks of aerobic training vs a control/comparator and reporting HRV and/or HRR/RHR.

Outcomes: Primary—HRV indices (RMSSD, HF, LF/HF). Secondary—post-exercise HRR, resting HR (RHR).
Results: Two controlled trials (total n≈82 completers) met criteria: (1) an RCT in habitual male smokers (8 weeks treadmill training, high- vs moderate-intensity vs control) reporting significant increases in RMSSD and HF and a decrease in LF/HF, favouring high-intensity training; (2) an 8-week cycle-based HIIT vs continuous aerobic training (CAT) vs control trial in college-aged smokers showing significant reductions in RHR vs control. A post-only standardized mean difference (Hedges g) for RHR from the latter trial showed large effects vs control (HIIT g≈−1.93; CAT g≈−1.91).

Conclusions: Limited but consistent evidence suggests aerobic training—especially higher intensity—improves cardiac autonomic balance in smokers, increasing vagal modulation (HRV) and lowering resting heart rate. Certainty is low to moderate due to few trials and some reporting limitations. More multi-arm RCTs with standardized HRV/HRR protocols are needed.