Influence of waterpipe smoking on cardiac autonomic function at rest and following high-intensity anaerobic exercise

Background: Waterpipe (WP) smoking has been linked to reduced birth weight, genetic damage, and respiratory and cardiovascular disease, possibly via enhanced exposure to carbon monoxide and volatile aldehydes. Objective: The effect of long-term WP smoking on cardiac autonomic function at rest and following exercise was investigated. Methods: Twenty males volunteered and were divided into two groups: WP smokers (WPS) and non-smokers (NSmk). Heart rate variability (HRV) at rest and following (10 mins) Wingate test was examined. Additionally, heart rate recovery (HRR) at 1 (HRR1), 2 (HRR2) and 5 mins (HRR5) post-Wingate test were considered. Results: At rest, the WPS group exhibited a significantly greater heart rate and lower standard deviation of RR intervals. The WPS group experienced a significantly greater peak heart rate while the post-Wingate recovery of HRV, HRR1, and HRR2 were similar between groups. In contrast, HRR5 for the WPS group was significantly greater than for the NSmk group. Conclusions: Long-term WP smoking resulted in an altered resting cardiac autonomic state exemplified by reduced overall HRV, specifically, a decline in vagal activity and/or relative increase in sympathetic activity that may persist during anaerobic exercise but not during early recovery.