Compared to the general public, people with alcohol use disorder have reduced heart rate variability (a measure of brain-heart system health), which can negatively influence behavioral and emotional regulation, common targets in addiction treatment. This study investigated the association between heart rate variability and alcohol abstinence over time among individuals seeking recovery.
l
The brain regions associated with the development and maintenance of alcohol and other drug use disorder (i.e., substance use disorder) also play an important role in brain-body interactions occurring outside of conscious awareness that regulate moment-to-moment changes in basic functions (e.g., sleeping, breathing, heart rate) as well as stress when faced with challenging situations. These brain-body interactions are thought to contribute to one’s ability to regulate their emotional and behavioral states.
One way to objectively measure the activity of this brain-body system is to assess its effects on the cardiovascular system by measuring heart rate variability. Heart rate variability is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with larger variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges. People with alcohol use disorder tend to have lower heart rate variability compared to the general public, which can negatively influence emotional/behavioral regulation. Negative emotional states, like anxiety and stress, can enhance motivation to drink and, in turn, increase risk of relapse among individuals with alcohol use disorder.
Though the relationship between heart rate variability and alcohol use has been demonstrated among individuals with alcohol use disorder in the laboratory setting, understanding heart rate variability in the context of real-world settings is also important because controlled laboratory settings do not accurately reflect the number or intensity of stressors people face in naturalistic settings. Examining whether and in what ways heart-brain system activity is associated with recovery process and outcomes can inform new treatments that target this brain-body. This study investigated real-time measures of heart rate variability collected in real-world settings among individuals seeking recovery from alcohol use disorder, and their relationship to alcohol abstinence over 3 months.
This was a prospective cohort study examining heart rate variability in real-world settings among 37 adults seeking recovery from an alcohol use disorder, and its relationship to alcohol abstinence days over a 90-day follow-up period. Participants were adults meeting DSM-5 criteria for alcohol use disorder attending treatment or mutual-help groups with a goal of abstinence. They needed to have 2 weeks of abstinence to participate because withdrawal symptoms (which would occur within days of initiating abstinence) affect heart rate variability, making it difficult to determine the degree to which these brain-body markers were associated with abstinence. People with current substance use disorders apart from alcohol were not able to participate.
Participants completed a baseline study session (upon study enrollment), at which time they were fitted with an electrocardiogram, which they took home with them and wore for four days to record their heart activity as they went about their every-day lives. The electrocardiogram equipment resembled an elastic exercise belt that was worn around the chest, under clothing. Participants were told to wear the device at all times during the 4-day period, except when sleeping.
During the 4-day recording period, participants were prompted to complete real-time, self-reported questionnaires about how they were feeling at random times throughout the day (i.e. 3 random survey prompts per day). Electrocardiogram recordings that were taken within 5 minutes of real-time survey responses were evaluated.
Ninety days after the 4-day heart measurement period, participants answered questions about their alcohol use. The primary outcome was self-reported alcohol use frequency (assessed with the timeline follow back to aid memory recall) measured as percent days abstinent during the 90-day follow-up period. Heart rate variability measures reflecting brain-heart system activity were extracted from electrocardiogram recordings gathered over the 4-day period. Measures primarily reflected parasympathetic activation of the autonomic nervous system (i.e. nervous system active during “rest and digest” conditions) and included:
1. Heart rate: the number of beats per minute.
2. SDNN: the standard deviation (i.e. variability) of the time between heart beats, which is measured in milliseconds (ms) and reflects overall heart rate variability (i.e. parasympathetic activation with sympathetic [‘fight or flight’ activity in stressful situations] activity influence).
3. RMSSD: the Root mean square of successive differences between heartbeats, which is measured in ms and reflects parasympathetic activity of the autonomic nervous system.
4. pNN50: The percentage of adjacent heartbeat intervals that differ from each other by more than 50 ms, which reflects parasympathetic activity.
5. Triangular index: a geometric measure that calculates the integral of the beat-to-beat interval histogram divided by its height, and reflects overall heart rate variability.
6. HF heart rate variability: A measure of the high frequency range (between 0.15 Hz and 0.4 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic activity.
7. LF Heart rate variability: A measure of the low frequency range (between 0.04 Hz and 0.15 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic control with varying degrees of influence from sympathetic activity.
Lower heart rate and higher values on all other measures reflect greater neurocardiac, parasympathetic activity, the body’s ability to downshift when faces with stress.
The authors examined whether heart rate variability measures predicted percent days abstinent over 90-day follow up. Then they assessed whether heart rate variability measures moderate the relationship between percent days abstinent at baseline and follow up. Analyses were conducted with and without controlling for factors that can influence heart rate variability, including: (1) age, (2) motivation for recovery (measured with Commitment to Sobriety Scale), (3) drinking goal over the 90-day follow-up period (abstinence vs. moderation), (4) receiving medications for health conditions (yes/no), (5) physical movement and respiration during electrocardiogram recordings, (6) anxiety and depression (measured with State Anxiety Inventory & Beck Depression Inventory II), (7) alcohol use disorder severity (measured with Alcohol Dependence Scale).
The majority of participants were White (74%) men (62%), with an average age of 42 (range: 18-65 years old). On average, participants were experiencing mild symptoms of depression and anxiety at baseline. At the time of study enrollment, all participants had a past-year alcohol use disorder, were in the first year of a recovery attempt with the goal of achieving abstinence, and were participating in outpatient treatment or a mutual-help program. Fifty-eight percent of participants had consumed alcohol in the 30 days prior to study enrollment (average of 2 drinks per day). Participants had an average of 88 percent days abstinent in the 30 days before study start, and 90 percent days abstinent over the 90-day follow-up period.
Figure. Heart rate variability (HRV) is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with higher variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges.
Greater parasympathetic activity and lower heart rate were associated with more alcohol abstinence
Overall heart rate variability, as measured with SDNN, was within the healthy range (average = 56 ms) for this sample of people in early alcohol use disorder recovery. However, measures of parasympathetic heart-brain system activity (RMSSD and pNN50), were lower than the average healthy adult range (average = 24 ms and 7%, respectively).
Greater parasympathetic activity (higher values for RMSSD, pNN50, HF heart rate variability, LF heart rate variability, SDNN, and triangular index scores) and lower heart rate predicted more percent days abstinent over the 90-day follow-up period, with medium to large effects on alcohol use. These measures accounted for 11–17% of the variability in alcohol use at follow up.
Greater parasympathetic activity and lower heart rate attenuated the relationship between alcohol use at baseline and follow up
As would be expected, more percent days abstinent at baseline was associated with more percent days abstinent over 90-day follow up in the sample overall. Importantly, however, there was also a significant interaction between percent days abstinent at baseline and all heart rate variability measures. For those with lower parasympathetic activity and higher heart rate variability, there was a strong relationship between baseline and follow-up alcohol abstinence. In other words, for those who have lower abilities to self-regulate, worse initial abstinence predicted worse follow-up abstinence and better initial abstinence predicted better follow-up abstinence. For those with greater parasympathetic activity and lower heart rate, on the other hand, there was no such relationship – they had high rates of abstinence at follow up regardless of how much they were drinking at baseline (see figure below). For those with better ability to self-regulate, their initial abstinence was not a predictor of later abstinence — they had high rates of abstinence 3 months after entering the study irrespective of how they were doing when they began the study. Better brain-body response to stress, therefore, may buffer against any initial risks that people face in early recovery. When control variables were included in analyses, findings were unchanged.
Figure. Conceptual relationship between percent days abstinent at baseline and follow up, at varying degrees of heart rate variability aggregated across multiple measures. Overall, individuals with lower parasympathetic activity showed a strong correlation between alcohol use at baseline and follow-up (shown in red). Alternatively, for individuals with greater parasympathetic activity (shown in blue), their baseline and follow-up abstinence rates were essentially uncorrelated, with high abstinence rates regardless. Those with average levels of parasympathetic activity were in between.
This study was one of the first to demonstrate that real-world heart rate variability is associated with alcohol use outcomes – greater parasympathetic activity of the brain-heart system and lower heart rate predicted more days of alcohol abstinence over a 90-day follow up. Also, better cardiovascular functioning may buffer against risks present in early recovery. While those with lower abstinence early tended to have lower abstinence at follow-up (an indicator of early risks negatively impacting outcomes), those with better brain-heart health had 80-90 percent days abstinent regardless of their initial baseline risk.
These findings are important because impairment in parasympathetic brain-heart system activity contributes to the maintenance of substance use disorders, which can hinder successful recovery. Naturalistic studies like this also help to identify possible targets for new therapeutic techniques that support addiction recovery in real-world settings, with this study suggesting heart rate variability as a predictor (or marker) of recovery success.
Findings are consistent with prior research, which show impaired heart rate variability and its relationship to addiction-relevant emotional states (e.g., craving) among individuals with alcohol use disorder. This study replicates and extends those findings by measuring heart rate variability impairment among individuals seeking recovery from alcohol use disorder, and its relationship with alcohol consumption during the early stages of recovery. Theories of heart-brain systems suggest that lower parasympathetic heart-brain activity is a marker of problems regulating behavior and emotion. Recent research also suggests that errors in the brain’s ability to predict events might play a role in dysfunctional heart-brain reactions that negatively affect the body’s ability to adapt in response to challenging/stressful situations.
Chronic stress is associated with lower heart rate variability (i.e. reduced parasympathetic activity), and stress increases risk of alcohol use among individuals with alcohol use disorder. It may be that reduced parasympathetic activity of the heart-brain system disrupts the brain’s ability to interpret heart activity that influences attention and perception, which could in turn contribute to problems regulating emotions and behaviors (e.g., stress and alcohol use). Importantly, heart rate variability predicted alcohol use outcomes regardless of an individual’s motivation for recovery or their recovery goal (abstinence vs. moderation), highlighting the important role of heart-brain system functioning for supporting positive behavioral changes and recovery outcomes.
Findings also suggest that heart rate variability may be an ideal target for interventions aimed at supporting recovery outcomes. Interventions that increase parasympathetic heart-brain activity may be useful for increasing heart rate variability and, in turn, supporting reductions in alcohol use to support recovery. For example, rhythmic, paced breathing techniques are shown to help regulate the autonomic nervous system and, in turn, support emotional/behavioral regulation (e.g., reduced craving). Wearable technology, like smartwatches and fitness monitors are already widely available, many of which already provide some degree of heart rate variability monitoring. Though additional research is needed, developing just-in-time relapse prevention interventions (e.g., breathing techniques) that leverage these real-time heart rate variability measures may ultimately help to support early and sustained recovery.
Overall, individuals seeking recovery from alcohol use disorder had several impaired markers of heart rate variability compared to healthy adult norms. Greater heart-brain system dysfunction (i.e. lower parasympathetic heart-brain system activity reflecting lower heart rate variability) was associated with greater alcohol use 90 days later, regardless of the amount of alcohol consumed at baseline. Thus, this study highlights the potential value of heart rate variability for predicting risk of alcohol-use relapse among individuals seeking recovery from alcohol use disorder. Measures of heart rate variability can be easily obtained in multiple settings (e.g., using wearable technology in the real-world or clinical setting) and simple techniques like paced breathing can positively influence heart rate variability. Future research will help identify whether just-in-time relapse prevention interventions that leverage these real-time heart rate variability measures and techniques can be used to help support early and sustained recovery.
Eddie, D., Wieman, S., Pietrzak, A., & Zhai, X. (2023). In natura heart rate variability predicts subsequent alcohol use in individuals in early recovery from alcohol use disorder. Addiction Biology, 28(8), e13306. doi: 10.1111/adb.13306
l
The brain regions associated with the development and maintenance of alcohol and other drug use disorder (i.e., substance use disorder) also play an important role in brain-body interactions occurring outside of conscious awareness that regulate moment-to-moment changes in basic functions (e.g., sleeping, breathing, heart rate) as well as stress when faced with challenging situations. These brain-body interactions are thought to contribute to one’s ability to regulate their emotional and behavioral states.
One way to objectively measure the activity of this brain-body system is to assess its effects on the cardiovascular system by measuring heart rate variability. Heart rate variability is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with larger variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges. People with alcohol use disorder tend to have lower heart rate variability compared to the general public, which can negatively influence emotional/behavioral regulation. Negative emotional states, like anxiety and stress, can enhance motivation to drink and, in turn, increase risk of relapse among individuals with alcohol use disorder.
Though the relationship between heart rate variability and alcohol use has been demonstrated among individuals with alcohol use disorder in the laboratory setting, understanding heart rate variability in the context of real-world settings is also important because controlled laboratory settings do not accurately reflect the number or intensity of stressors people face in naturalistic settings. Examining whether and in what ways heart-brain system activity is associated with recovery process and outcomes can inform new treatments that target this brain-body. This study investigated real-time measures of heart rate variability collected in real-world settings among individuals seeking recovery from alcohol use disorder, and their relationship to alcohol abstinence over 3 months.
This was a prospective cohort study examining heart rate variability in real-world settings among 37 adults seeking recovery from an alcohol use disorder, and its relationship to alcohol abstinence days over a 90-day follow-up period. Participants were adults meeting DSM-5 criteria for alcohol use disorder attending treatment or mutual-help groups with a goal of abstinence. They needed to have 2 weeks of abstinence to participate because withdrawal symptoms (which would occur within days of initiating abstinence) affect heart rate variability, making it difficult to determine the degree to which these brain-body markers were associated with abstinence. People with current substance use disorders apart from alcohol were not able to participate.
Participants completed a baseline study session (upon study enrollment), at which time they were fitted with an electrocardiogram, which they took home with them and wore for four days to record their heart activity as they went about their every-day lives. The electrocardiogram equipment resembled an elastic exercise belt that was worn around the chest, under clothing. Participants were told to wear the device at all times during the 4-day period, except when sleeping.
During the 4-day recording period, participants were prompted to complete real-time, self-reported questionnaires about how they were feeling at random times throughout the day (i.e. 3 random survey prompts per day). Electrocardiogram recordings that were taken within 5 minutes of real-time survey responses were evaluated.
Ninety days after the 4-day heart measurement period, participants answered questions about their alcohol use. The primary outcome was self-reported alcohol use frequency (assessed with the timeline follow back to aid memory recall) measured as percent days abstinent during the 90-day follow-up period. Heart rate variability measures reflecting brain-heart system activity were extracted from electrocardiogram recordings gathered over the 4-day period. Measures primarily reflected parasympathetic activation of the autonomic nervous system (i.e. nervous system active during “rest and digest” conditions) and included:
1. Heart rate: the number of beats per minute.
2. SDNN: the standard deviation (i.e. variability) of the time between heart beats, which is measured in milliseconds (ms) and reflects overall heart rate variability (i.e. parasympathetic activation with sympathetic [‘fight or flight’ activity in stressful situations] activity influence).
3. RMSSD: the Root mean square of successive differences between heartbeats, which is measured in ms and reflects parasympathetic activity of the autonomic nervous system.
4. pNN50: The percentage of adjacent heartbeat intervals that differ from each other by more than 50 ms, which reflects parasympathetic activity.
5. Triangular index: a geometric measure that calculates the integral of the beat-to-beat interval histogram divided by its height, and reflects overall heart rate variability.
6. HF heart rate variability: A measure of the high frequency range (between 0.15 Hz and 0.4 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic activity.
7. LF Heart rate variability: A measure of the low frequency range (between 0.04 Hz and 0.15 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic control with varying degrees of influence from sympathetic activity.
Lower heart rate and higher values on all other measures reflect greater neurocardiac, parasympathetic activity, the body’s ability to downshift when faces with stress.
The authors examined whether heart rate variability measures predicted percent days abstinent over 90-day follow up. Then they assessed whether heart rate variability measures moderate the relationship between percent days abstinent at baseline and follow up. Analyses were conducted with and without controlling for factors that can influence heart rate variability, including: (1) age, (2) motivation for recovery (measured with Commitment to Sobriety Scale), (3) drinking goal over the 90-day follow-up period (abstinence vs. moderation), (4) receiving medications for health conditions (yes/no), (5) physical movement and respiration during electrocardiogram recordings, (6) anxiety and depression (measured with State Anxiety Inventory & Beck Depression Inventory II), (7) alcohol use disorder severity (measured with Alcohol Dependence Scale).
The majority of participants were White (74%) men (62%), with an average age of 42 (range: 18-65 years old). On average, participants were experiencing mild symptoms of depression and anxiety at baseline. At the time of study enrollment, all participants had a past-year alcohol use disorder, were in the first year of a recovery attempt with the goal of achieving abstinence, and were participating in outpatient treatment or a mutual-help program. Fifty-eight percent of participants had consumed alcohol in the 30 days prior to study enrollment (average of 2 drinks per day). Participants had an average of 88 percent days abstinent in the 30 days before study start, and 90 percent days abstinent over the 90-day follow-up period.
Figure. Heart rate variability (HRV) is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with higher variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges.
Greater parasympathetic activity and lower heart rate were associated with more alcohol abstinence
Overall heart rate variability, as measured with SDNN, was within the healthy range (average = 56 ms) for this sample of people in early alcohol use disorder recovery. However, measures of parasympathetic heart-brain system activity (RMSSD and pNN50), were lower than the average healthy adult range (average = 24 ms and 7%, respectively).
Greater parasympathetic activity (higher values for RMSSD, pNN50, HF heart rate variability, LF heart rate variability, SDNN, and triangular index scores) and lower heart rate predicted more percent days abstinent over the 90-day follow-up period, with medium to large effects on alcohol use. These measures accounted for 11–17% of the variability in alcohol use at follow up.
Greater parasympathetic activity and lower heart rate attenuated the relationship between alcohol use at baseline and follow up
As would be expected, more percent days abstinent at baseline was associated with more percent days abstinent over 90-day follow up in the sample overall. Importantly, however, there was also a significant interaction between percent days abstinent at baseline and all heart rate variability measures. For those with lower parasympathetic activity and higher heart rate variability, there was a strong relationship between baseline and follow-up alcohol abstinence. In other words, for those who have lower abilities to self-regulate, worse initial abstinence predicted worse follow-up abstinence and better initial abstinence predicted better follow-up abstinence. For those with greater parasympathetic activity and lower heart rate, on the other hand, there was no such relationship – they had high rates of abstinence at follow up regardless of how much they were drinking at baseline (see figure below). For those with better ability to self-regulate, their initial abstinence was not a predictor of later abstinence — they had high rates of abstinence 3 months after entering the study irrespective of how they were doing when they began the study. Better brain-body response to stress, therefore, may buffer against any initial risks that people face in early recovery. When control variables were included in analyses, findings were unchanged.
Figure. Conceptual relationship between percent days abstinent at baseline and follow up, at varying degrees of heart rate variability aggregated across multiple measures. Overall, individuals with lower parasympathetic activity showed a strong correlation between alcohol use at baseline and follow-up (shown in red). Alternatively, for individuals with greater parasympathetic activity (shown in blue), their baseline and follow-up abstinence rates were essentially uncorrelated, with high abstinence rates regardless. Those with average levels of parasympathetic activity were in between.
This study was one of the first to demonstrate that real-world heart rate variability is associated with alcohol use outcomes – greater parasympathetic activity of the brain-heart system and lower heart rate predicted more days of alcohol abstinence over a 90-day follow up. Also, better cardiovascular functioning may buffer against risks present in early recovery. While those with lower abstinence early tended to have lower abstinence at follow-up (an indicator of early risks negatively impacting outcomes), those with better brain-heart health had 80-90 percent days abstinent regardless of their initial baseline risk.
These findings are important because impairment in parasympathetic brain-heart system activity contributes to the maintenance of substance use disorders, which can hinder successful recovery. Naturalistic studies like this also help to identify possible targets for new therapeutic techniques that support addiction recovery in real-world settings, with this study suggesting heart rate variability as a predictor (or marker) of recovery success.
Findings are consistent with prior research, which show impaired heart rate variability and its relationship to addiction-relevant emotional states (e.g., craving) among individuals with alcohol use disorder. This study replicates and extends those findings by measuring heart rate variability impairment among individuals seeking recovery from alcohol use disorder, and its relationship with alcohol consumption during the early stages of recovery. Theories of heart-brain systems suggest that lower parasympathetic heart-brain activity is a marker of problems regulating behavior and emotion. Recent research also suggests that errors in the brain’s ability to predict events might play a role in dysfunctional heart-brain reactions that negatively affect the body’s ability to adapt in response to challenging/stressful situations.
Chronic stress is associated with lower heart rate variability (i.e. reduced parasympathetic activity), and stress increases risk of alcohol use among individuals with alcohol use disorder. It may be that reduced parasympathetic activity of the heart-brain system disrupts the brain’s ability to interpret heart activity that influences attention and perception, which could in turn contribute to problems regulating emotions and behaviors (e.g., stress and alcohol use). Importantly, heart rate variability predicted alcohol use outcomes regardless of an individual’s motivation for recovery or their recovery goal (abstinence vs. moderation), highlighting the important role of heart-brain system functioning for supporting positive behavioral changes and recovery outcomes.
Findings also suggest that heart rate variability may be an ideal target for interventions aimed at supporting recovery outcomes. Interventions that increase parasympathetic heart-brain activity may be useful for increasing heart rate variability and, in turn, supporting reductions in alcohol use to support recovery. For example, rhythmic, paced breathing techniques are shown to help regulate the autonomic nervous system and, in turn, support emotional/behavioral regulation (e.g., reduced craving). Wearable technology, like smartwatches and fitness monitors are already widely available, many of which already provide some degree of heart rate variability monitoring. Though additional research is needed, developing just-in-time relapse prevention interventions (e.g., breathing techniques) that leverage these real-time heart rate variability measures may ultimately help to support early and sustained recovery.
Overall, individuals seeking recovery from alcohol use disorder had several impaired markers of heart rate variability compared to healthy adult norms. Greater heart-brain system dysfunction (i.e. lower parasympathetic heart-brain system activity reflecting lower heart rate variability) was associated with greater alcohol use 90 days later, regardless of the amount of alcohol consumed at baseline. Thus, this study highlights the potential value of heart rate variability for predicting risk of alcohol-use relapse among individuals seeking recovery from alcohol use disorder. Measures of heart rate variability can be easily obtained in multiple settings (e.g., using wearable technology in the real-world or clinical setting) and simple techniques like paced breathing can positively influence heart rate variability. Future research will help identify whether just-in-time relapse prevention interventions that leverage these real-time heart rate variability measures and techniques can be used to help support early and sustained recovery.
Eddie, D., Wieman, S., Pietrzak, A., & Zhai, X. (2023). In natura heart rate variability predicts subsequent alcohol use in individuals in early recovery from alcohol use disorder. Addiction Biology, 28(8), e13306. doi: 10.1111/adb.13306
l
The brain regions associated with the development and maintenance of alcohol and other drug use disorder (i.e., substance use disorder) also play an important role in brain-body interactions occurring outside of conscious awareness that regulate moment-to-moment changes in basic functions (e.g., sleeping, breathing, heart rate) as well as stress when faced with challenging situations. These brain-body interactions are thought to contribute to one’s ability to regulate their emotional and behavioral states.
One way to objectively measure the activity of this brain-body system is to assess its effects on the cardiovascular system by measuring heart rate variability. Heart rate variability is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with larger variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges. People with alcohol use disorder tend to have lower heart rate variability compared to the general public, which can negatively influence emotional/behavioral regulation. Negative emotional states, like anxiety and stress, can enhance motivation to drink and, in turn, increase risk of relapse among individuals with alcohol use disorder.
Though the relationship between heart rate variability and alcohol use has been demonstrated among individuals with alcohol use disorder in the laboratory setting, understanding heart rate variability in the context of real-world settings is also important because controlled laboratory settings do not accurately reflect the number or intensity of stressors people face in naturalistic settings. Examining whether and in what ways heart-brain system activity is associated with recovery process and outcomes can inform new treatments that target this brain-body. This study investigated real-time measures of heart rate variability collected in real-world settings among individuals seeking recovery from alcohol use disorder, and their relationship to alcohol abstinence over 3 months.
This was a prospective cohort study examining heart rate variability in real-world settings among 37 adults seeking recovery from an alcohol use disorder, and its relationship to alcohol abstinence days over a 90-day follow-up period. Participants were adults meeting DSM-5 criteria for alcohol use disorder attending treatment or mutual-help groups with a goal of abstinence. They needed to have 2 weeks of abstinence to participate because withdrawal symptoms (which would occur within days of initiating abstinence) affect heart rate variability, making it difficult to determine the degree to which these brain-body markers were associated with abstinence. People with current substance use disorders apart from alcohol were not able to participate.
Participants completed a baseline study session (upon study enrollment), at which time they were fitted with an electrocardiogram, which they took home with them and wore for four days to record their heart activity as they went about their every-day lives. The electrocardiogram equipment resembled an elastic exercise belt that was worn around the chest, under clothing. Participants were told to wear the device at all times during the 4-day period, except when sleeping.
During the 4-day recording period, participants were prompted to complete real-time, self-reported questionnaires about how they were feeling at random times throughout the day (i.e. 3 random survey prompts per day). Electrocardiogram recordings that were taken within 5 minutes of real-time survey responses were evaluated.
Ninety days after the 4-day heart measurement period, participants answered questions about their alcohol use. The primary outcome was self-reported alcohol use frequency (assessed with the timeline follow back to aid memory recall) measured as percent days abstinent during the 90-day follow-up period. Heart rate variability measures reflecting brain-heart system activity were extracted from electrocardiogram recordings gathered over the 4-day period. Measures primarily reflected parasympathetic activation of the autonomic nervous system (i.e. nervous system active during “rest and digest” conditions) and included:
1. Heart rate: the number of beats per minute.
2. SDNN: the standard deviation (i.e. variability) of the time between heart beats, which is measured in milliseconds (ms) and reflects overall heart rate variability (i.e. parasympathetic activation with sympathetic [‘fight or flight’ activity in stressful situations] activity influence).
3. RMSSD: the Root mean square of successive differences between heartbeats, which is measured in ms and reflects parasympathetic activity of the autonomic nervous system.
4. pNN50: The percentage of adjacent heartbeat intervals that differ from each other by more than 50 ms, which reflects parasympathetic activity.
5. Triangular index: a geometric measure that calculates the integral of the beat-to-beat interval histogram divided by its height, and reflects overall heart rate variability.
6. HF heart rate variability: A measure of the high frequency range (between 0.15 Hz and 0.4 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic activity.
7. LF Heart rate variability: A measure of the low frequency range (between 0.04 Hz and 0.15 Hz) of electrocardiogram recordings that is assessed as ms2 and thought to reflect parasympathetic control with varying degrees of influence from sympathetic activity.
Lower heart rate and higher values on all other measures reflect greater neurocardiac, parasympathetic activity, the body’s ability to downshift when faces with stress.
The authors examined whether heart rate variability measures predicted percent days abstinent over 90-day follow up. Then they assessed whether heart rate variability measures moderate the relationship between percent days abstinent at baseline and follow up. Analyses were conducted with and without controlling for factors that can influence heart rate variability, including: (1) age, (2) motivation for recovery (measured with Commitment to Sobriety Scale), (3) drinking goal over the 90-day follow-up period (abstinence vs. moderation), (4) receiving medications for health conditions (yes/no), (5) physical movement and respiration during electrocardiogram recordings, (6) anxiety and depression (measured with State Anxiety Inventory & Beck Depression Inventory II), (7) alcohol use disorder severity (measured with Alcohol Dependence Scale).
The majority of participants were White (74%) men (62%), with an average age of 42 (range: 18-65 years old). On average, participants were experiencing mild symptoms of depression and anxiety at baseline. At the time of study enrollment, all participants had a past-year alcohol use disorder, were in the first year of a recovery attempt with the goal of achieving abstinence, and were participating in outpatient treatment or a mutual-help program. Fifty-eight percent of participants had consumed alcohol in the 30 days prior to study enrollment (average of 2 drinks per day). Participants had an average of 88 percent days abstinent in the 30 days before study start, and 90 percent days abstinent over the 90-day follow-up period.
Figure. Heart rate variability (HRV) is a measure of the amount of fluctuation in the time between a person’s heartbeats – it reflects heart-brain interactions and is a marker of health, with higher variability suggesting better health and emotion regulation, and greater ability to adapt to demands and challenges.
Greater parasympathetic activity and lower heart rate were associated with more alcohol abstinence
Overall heart rate variability, as measured with SDNN, was within the healthy range (average = 56 ms) for this sample of people in early alcohol use disorder recovery. However, measures of parasympathetic heart-brain system activity (RMSSD and pNN50), were lower than the average healthy adult range (average = 24 ms and 7%, respectively).
Greater parasympathetic activity (higher values for RMSSD, pNN50, HF heart rate variability, LF heart rate variability, SDNN, and triangular index scores) and lower heart rate predicted more percent days abstinent over the 90-day follow-up period, with medium to large effects on alcohol use. These measures accounted for 11–17% of the variability in alcohol use at follow up.
Greater parasympathetic activity and lower heart rate attenuated the relationship between alcohol use at baseline and follow up
As would be expected, more percent days abstinent at baseline was associated with more percent days abstinent over 90-day follow up in the sample overall. Importantly, however, there was also a significant interaction between percent days abstinent at baseline and all heart rate variability measures. For those with lower parasympathetic activity and higher heart rate variability, there was a strong relationship between baseline and follow-up alcohol abstinence. In other words, for those who have lower abilities to self-regulate, worse initial abstinence predicted worse follow-up abstinence and better initial abstinence predicted better follow-up abstinence. For those with greater parasympathetic activity and lower heart rate, on the other hand, there was no such relationship – they had high rates of abstinence at follow up regardless of how much they were drinking at baseline (see figure below). For those with better ability to self-regulate, their initial abstinence was not a predictor of later abstinence — they had high rates of abstinence 3 months after entering the study irrespective of how they were doing when they began the study. Better brain-body response to stress, therefore, may buffer against any initial risks that people face in early recovery. When control variables were included in analyses, findings were unchanged.
Figure. Conceptual relationship between percent days abstinent at baseline and follow up, at varying degrees of heart rate variability aggregated across multiple measures. Overall, individuals with lower parasympathetic activity showed a strong correlation between alcohol use at baseline and follow-up (shown in red). Alternatively, for individuals with greater parasympathetic activity (shown in blue), their baseline and follow-up abstinence rates were essentially uncorrelated, with high abstinence rates regardless. Those with average levels of parasympathetic activity were in between.
This study was one of the first to demonstrate that real-world heart rate variability is associated with alcohol use outcomes – greater parasympathetic activity of the brain-heart system and lower heart rate predicted more days of alcohol abstinence over a 90-day follow up. Also, better cardiovascular functioning may buffer against risks present in early recovery. While those with lower abstinence early tended to have lower abstinence at follow-up (an indicator of early risks negatively impacting outcomes), those with better brain-heart health had 80-90 percent days abstinent regardless of their initial baseline risk.
These findings are important because impairment in parasympathetic brain-heart system activity contributes to the maintenance of substance use disorders, which can hinder successful recovery. Naturalistic studies like this also help to identify possible targets for new therapeutic techniques that support addiction recovery in real-world settings, with this study suggesting heart rate variability as a predictor (or marker) of recovery success.
Findings are consistent with prior research, which show impaired heart rate variability and its relationship to addiction-relevant emotional states (e.g., craving) among individuals with alcohol use disorder. This study replicates and extends those findings by measuring heart rate variability impairment among individuals seeking recovery from alcohol use disorder, and its relationship with alcohol consumption during the early stages of recovery. Theories of heart-brain systems suggest that lower parasympathetic heart-brain activity is a marker of problems regulating behavior and emotion. Recent research also suggests that errors in the brain’s ability to predict events might play a role in dysfunctional heart-brain reactions that negatively affect the body’s ability to adapt in response to challenging/stressful situations.
Chronic stress is associated with lower heart rate variability (i.e. reduced parasympathetic activity), and stress increases risk of alcohol use among individuals with alcohol use disorder. It may be that reduced parasympathetic activity of the heart-brain system disrupts the brain’s ability to interpret heart activity that influences attention and perception, which could in turn contribute to problems regulating emotions and behaviors (e.g., stress and alcohol use). Importantly, heart rate variability predicted alcohol use outcomes regardless of an individual’s motivation for recovery or their recovery goal (abstinence vs. moderation), highlighting the important role of heart-brain system functioning for supporting positive behavioral changes and recovery outcomes.
Findings also suggest that heart rate variability may be an ideal target for interventions aimed at supporting recovery outcomes. Interventions that increase parasympathetic heart-brain activity may be useful for increasing heart rate variability and, in turn, supporting reductions in alcohol use to support recovery. For example, rhythmic, paced breathing techniques are shown to help regulate the autonomic nervous system and, in turn, support emotional/behavioral regulation (e.g., reduced craving). Wearable technology, like smartwatches and fitness monitors are already widely available, many of which already provide some degree of heart rate variability monitoring. Though additional research is needed, developing just-in-time relapse prevention interventions (e.g., breathing techniques) that leverage these real-time heart rate variability measures may ultimately help to support early and sustained recovery.
Overall, individuals seeking recovery from alcohol use disorder had several impaired markers of heart rate variability compared to healthy adult norms. Greater heart-brain system dysfunction (i.e. lower parasympathetic heart-brain system activity reflecting lower heart rate variability) was associated with greater alcohol use 90 days later, regardless of the amount of alcohol consumed at baseline. Thus, this study highlights the potential value of heart rate variability for predicting risk of alcohol-use relapse among individuals seeking recovery from alcohol use disorder. Measures of heart rate variability can be easily obtained in multiple settings (e.g., using wearable technology in the real-world or clinical setting) and simple techniques like paced breathing can positively influence heart rate variability. Future research will help identify whether just-in-time relapse prevention interventions that leverage these real-time heart rate variability measures and techniques can be used to help support early and sustained recovery.
Eddie, D., Wieman, S., Pietrzak, A., & Zhai, X. (2023). In natura heart rate variability predicts subsequent alcohol use in individuals in early recovery from alcohol use disorder. Addiction Biology, 28(8), e13306. doi: 10.1111/adb.13306
SIGN UP FOR THE BULLETIN
