Cardiorespiratory Fitness Predicts Greater Vagal Autonomic Activity in Drug Users Under Stress

Abstract

While drug use has been shown to impair cardiac autonomic regulation, exercise might overcome some of the damage. Herein, we describe how individuals with substance use disorder (SUD) have their heart rate variability (HRV) and drug-related behaviors negatively affected in response to a stressor. However, we show how cardiorespiratory fitness may attenuate those impairments in autonomic control. Fifteen individuals with SUD were matched with 15 non-SUD individuals by age, weight, height, and fitness level, and had their HRV responses under stress induced by the Cold Pressor Test (CPT). The SUD group had lower mean of R-R intervals before and after the CPT when compared with the non-SUD group. In addition, in individuals with SUD, higher cardiorespiratory fitness level predicted greater vagal activity before, during, and after CPT. Moreover, for individuals with SUD, days of abstinence predicted greater mean of R-R intervals during recovery from the CPT. Finally, years of drug use negatively predicted mean of R-R intervals during recovery. Thus, our results suggest that chronic drug use impairs cardiac autonomic regulation at rest and after a physical stress. However, cardiorespiratory fitness might attenuate these impairments by increasing vagal autonomic activity.

Heart Rate Variability in Adults With Substance Use Disorder: A Comprehensive Narrative Review

“…Overall, the difference in resting HRV was found between healthy controls and individuals with OUD or other SUD (i.e., heroin, cocaine, fentanyl, and methamphetamine) but not between opioid misusers and non-misusers receiving prescription opioids for pain. Lower resting HRV indices in the time (i.e., SDNN, RMSS, and Pnn50), frequency (i.e., HF-HRV), and nonlinear (i.e., SampEN) domain were found in individuals with OUD or other drug dependence compared to healthy controls (Cabral et al, 2019; Chang et al, 2012; Dolezal et al, 2014; Henry et al, 2012). When specifically comparing frequency HRV values (i.e., HF-HRV) between patients with OUD and healthy controls, significantly lower HRV was reported in patients with OUD (Chang et al, 2012).…”

“…Recovery HRV is the HRV measured after the event of stress. All studies report HRV outcomes during rest, and only a few studies include reactive (Baker & Garland, 2019; Cabral et al, 2019; Garland et al, 2017, 2018; Kroll et al, 2019; Levin et al, 2019) or recovery HRV (Cabral et al, 2019) in response to a stressor or cue.…”

“…A summary of the key HRV parameters and measures is in Table 2. The majority of the studies included time and frequency domains, but root mean square of the successive differences (RMSSD) was the most commonly used HRV index across the studies, with emphasis on its strength of being less affected by respiratory influences (Baker & Garland, 2019) and having a good representation of vagal tone (Cabral et al, 2019).…”

“…Several studies analyzed the sequential RR intervals derived from the ECG signals and used analysis programs to automatically detect the intervals, which were also followed by visual inspections (Baker & Garland, 2019; Garland et al, 2014, 2015, 2017; Henry et al, 2012). Some studies took further measures to minimize artifacts (e.g., skipped beats) by using selected analysis software programs to automatically detect RR intervals and also visually inspect for misidentified or excluded intervals (Cabral et al, 2019; Chang et al, 2012; D’Souza et al, 2019; Garland et al, 2018). An example of the threshold used was a noise rejection interval of 5% of the RR range and a window of 40 to 120 beats/min (D’Souza et al, 2019).…”

“…An example of the threshold used was a noise rejection interval of 5% of the RR range and a window of 40 to 120 beats/min (D’Souza et al, 2019). An interpolation algorithm was also used to correct corrupted RR intervals by replacing them with interpolated RR values (Cabral et al, 2019).…”