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The current proceedings summarize the presentations held during the 12th meeting of the Alcohol Hangover Research Group (AHRG) in 2022, in Buenos Aires, Argentina. The aim of the annual AHRG meeting was to discuss advances in research on the causes, consequences, and possible treatment of the alcohol hangover, including methodological issues and the possibilities for future research collaboration.

The alcohol hangover is defined as the combination of negative mental and physical symptoms that can be experienced after a single episode of alcohol consumption, starting when the blood alcohol concentration (BAC) approaches zero. Alcohol hangover symptoms such as fatigue, nausea, and headache can negatively affect daily activities, including work performance. The alcohol hangover can therefore be a cause of both absenteeism (not going to work) and presenteeism (going to work while hungover). An online survey among a convenience sample of n = 347 Dutch adults examined the number of days of absenteeism and presenteeism associated with having a hangover as well as the loss of productivity when going to work when hungover during the year 2019. In the Dutch sample, 8.1% of employees reported one or more days of absenteeism due to hangover in 2019, and 33.4% reported one or more days of presenteeism. The analyses revealed that alcohol hangover was associated with 0.2 days of absenteeism and 8.3 days of presenteeism and a productivity loss of 24.9% on days worked with a hangover. The estimated associated costs for the Dutch economy in 2019 of absenteeism (EUR 234,538,460) and presenteeism (EUR 2,423,603,184) total EUR 2,658,141,644. In conclusion, the alcohol hangover is associated with absenteeism, presenteeism, and reduced performance at work while hungover. As such, the annual costs of the alcohol hangover have a significant impact on the Dutch economy. However, these first findings on the economic costs of the alcohol hangover should be considered a rough estimate. They should be verified in a longitudinal study to minimize recall bias, including a nationally representative sample of sufficient sample size.

Mental resilience is the ability to bounce back from daily life stressors such as divorce or losing a job. Extensive research has demonstrated a negative relationship between mental resilience and alcohol consumption. That is, both the quantity and frequency of alcohol consumption are greater in individuals with lower levels of mental resilience. There has, however, been little scientific attention paid to the relationship between mental resilience and alcohol hangover severity. The objective of this study was to evaluate psychological factors that may impact the frequency and severity of alcohol hangovers, including alcohol intake itself, mental resilience, personality, baseline mood, lifestyle, and coping mechanisms. An online survey was conducted among Dutch adults (N = 153) who had a hangover after their heaviest drinking occasion in the period before the start of the COVID-19 pandemic (15 January to 14 March 2020). Questions were asked about their alcohol consumption and hangover severity on their heaviest drinking occasion. Mental resilience was assessed with the Brief Mental Resilience scale, personality with the Eysenck Personality Questionnaire–Revised Short Scale (EPQ-RSS), mood via single item assessments, and lifestyle and coping with the modified Fantastic Lifestyle Checklist. The partial correlation, corrected for estimated peak blood alcohol concentration (BAC), between mental resilience and hangover severity was not significant (r = 0.010, p = 0.848). Furthermore, no significant correlations were found between hangover severity or frequency and personality and baseline mood. For lifestyle and coping factors, a negative correlation was found between the use of tobacco and toxins (i.e., drugs, medicines, caffeine) and the frequency of experiencing hangovers. Regression analysis revealed that hangover severity after the heaviest drinking occasion (31.2%) was the best predictor of hangover frequency, and that subjective intoxication on the heaviest drinking occasion (38.4%) was the best predictor of next-day hangover severity. Mood, mental resilience, and personality were not relevant predictors of hangover frequency and severity. In conclusion, mental resilience, personality, and baseline mood do not predict hangover frequency and severity.

This study investigated potential differences in baseline (i.e., non-hangover-related) levels of depression, anxiety, and stress between individuals who are sensitive to and those resistant to hangovers after consuming alcohol. Participants included 5111 university students from the Netherlands and the U.K., including 3205 hangover-sensitive and 1906 hangover-resistant drinkers. All participants completed surveys on their demographics, alcohol consumption, and hangover susceptibility (whether they experienced a hangover in the past 12 months), as well as their baseline levels of depression, anxiety, and stress on the DASS-21 scale. The results showed that hangover-sensitive drinkers had significantly higher levels of anxiety and stress, but not depression, compared to hangover-resistant drinkers. However, the observed differences between the two groups were small, with a magnitude of less than 1 out of 42 points on the DASS-21 anxiety and stress subscales, and are thus unlikely to be clinically meaningful.

The combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero, are collectively referred to as the alcohol hangover. Previous research revealed that 10 to 20% of drinkers claim not to experience next-day hangovers. Past studies were usually limited to single timepoint assessments. The aim of the current semi-naturalistic study was to compare the next-day effects of an evening of alcohol consumption of self-reported hangover-resistant drinkers (n = 14) with those of a group of self-reported hangover-sensitive drinkers (n = 15) at hourly timepoint throughout the day (09:30 until 15:30). Assessments of 23 hangover symptoms, mood (Profiles of Mood States-Short Form), and daytime sleepiness (Karolinska Sleepiness Scale) were made hourly after both an alcohol day and an alcohol-free control day. Additional morning assessments were made for mood (State-Trait Anxiety Inventory-Y, Beck’s Depression Inventory-II), risk-taking behavior (RT-18), past night sleep (Groningen Sleep Quality Scale), alcohol consumption, and activities during the test days. No significant differences were found regarding the amount of alcohol consumed and the total sleep time of the two groups. The hangover-sensitive group reported having a hangover as well as the presence of a variety of hangover-related symptoms, which were most severe in the morning and then gradually decreased during the day. The most frequently reported and most severe symptoms were sleepiness and fatigue, concentration problems, and headache. In contrast, the hangover-resistant group reported the absence of a hangover and the presence and severity of next-day symptoms did not significantly differ from the control day, except for increased fatigue and reduced vigor. The next-day effects on sleepiness-related complaints and vigor were significantly more pronounced among hangover-sensitive drinkers compared to hangover-resistant drinkers. In conclusion, contrary to hangover-resistant drinkers, hangover-sensitive drinkers report a variety of hangover symptoms that gradually ease during the day, but are still present in the afternoon.

In Argentina, the 2019 coronavirus disease (COVID-19) pandemic led to serious changes to social interaction, health, economy, and education. Argentina experienced two extensive lockdown periods. University education remained virtual for almost two academic years. The purpose of the present work was to analyze the impact of the COVID-19 lockdowns in Argentina on alcohol consumption, hangover severity and smoking among university students in Buenos Aires. A retrospective online survey was conducted in 2021 among students of the University of Buenos Aires. Participants aged 18–35 years old were asked about the average number of alcoholic drinks and number of drinking days per week, binge drinking occasions, drunkenness, next day hangover severity, number of hangovers per month, and smoking behavior. The results showed that the first and second COVID-19 lockdowns were associated with significant reductions in both weekly alcohol consumption, and hangover severity and subjective intoxication on their heaviest drinking occasions. Males consumed significantly more alcohol than females, and older students (25–35 years old) consumed more alcohol than younger students (18–24 years old). In addition, younger students reduced the number of cigarettes smoked per day during the two lockdown periods while older students exhibited significantly more smoking days per week. In conclusion, the present work in Argentinian students revealed a significant reduction in weekly alcohol consumption, and subjective intoxication and hangover severity on their heaviest drinking occasions during the pandemic lockdown periods.

On 19 November 2021, the first Irish Alcohol Hangover Research Seminar was held at the Atlantic Technological University, Donegal. In these proceedings, the presentations of the seminar are summarized. Topics discussed included the pathology and treatment of the alcohol hangover, cognitive and functional consequences, and the impact of the COVID-19 pandemic and associated lockdowns on alcohol consumption and experiencing hangovers.

Abstract Objective Knowing the purpose of a clinical study may provoke expectancies among subjects that may influence the study outcome. For example, expectancies about a drug effect may cause subjects to put in more effort to counteract these effects on performance tasks, or cause stress or other mood alterations in anticipation of expected adverse effects. The objective of this study was to investigate to what extent expectancy effects will influence the magnitude of cognitive performance decrement in the alcohol hangover state. Results Forty subjects with a mean (SD) age of 24.0 (7.4) years old participated in a naturalistic study to examine the alcohol hangover effects on cognitive performance. Subjects in the expectancy group were informed of the purpose of the study. In the control group subjects were told that the purpose of the study was to investigate the effects of time of day on cognitive performance. Subjects consumed a mean (SD) of 12.9 (10.0) alcoholic drinks the night before testing. Cognitive tests included the Stroop test, Eriksen’s flanker test, a divided attention test, intra-extra dimensional set shifting test, spatial working memory test, and free word recall test. Expectancy effects did not differentially affect cognitive performance in the alcohol hangover state.

Abstract Objective Recent research comparing hangover sensitive drinkers with hangover resistant drinkers has revealed that experiencing alcohol hangovers is associated with significantly poorer self-reported immune functioning (p

In the Netherlands, the 2019 coronavirus (COVID-19) pandemic had a significant impact on daily life, with two extensive lockdowns enforced to combat the spread of the SARS-CoV-2 virus. These measures included the closure of bars and restaurants, and the transition from face-to-face to online education. A survey was conducted among Dutch pharmacy students and PhD-candidates to investigate the impact of COVID-19 lockdown on alcohol consumption, hangovers, and academic functioning. The analysis revealed a significant reduction in both quantity and frequency of alcohol consumption during the COVID-19 lockdown periods. This was accompanied with a significant reduction in hangover frequency and lower hangover severity during COVID-19 lockdown periods. The distribution of scores on academic performance showed great variability between respondents: while some participants reported impairment, others reported improved performance during the COVID-19 pandemic, or no change. Women reported that significantly more time investment was associated with maintaining these performance levels. Consistent among participants was the notion of reduced interactions with teachers and other students. Participants who reported more hangovers and most severe hangovers before COVID-19 benefited from the lockdown periods in terms of improved academic performance. Positive correlations were found between study grades/output and both the frequency and severity of hangovers experienced before COVID-19, suggesting that heavier drinkers, in particular, improved academic performance during the lockdown periods. In conclusion, COVID-19 lockdowns were associated with a significant reduction in both alcohol consumption and experiencing hangovers, which was, among heavier drinkers particularly, associated with significantly improved academic functioning.

Since the outbreak of the 2019 coronavirus (COVID-19) pandemic, lockdown periods have been installed to counteract the spread of the virus. These lockdowns, characterized by social isolation, have been associated with mood changes and increased stress. Individuals have used various strategies to cope with the negative effects of being in lockdown, including increasing the frequency and quantity of alcohol consumption. The aim of this study was to investigate mood before and during lockdown of individuals who reported consuming more, less, or the same amount of alcohol during lockdown, and examine how this impacts and perceived immune fitness and the presence and severity of COVID-19 symptoms. Analysis included a sub-sample from the ‘Corona Lockdown: how fit are you?’ (CLOFIT) study, comprising N = 761 participants who reported consuming alcohol in 2020. The results of the online survey showed that half of the participants did not alter their weekly alcohol consumption during lockdown (50.4%), whereas 25.9% of drinkers reported a reduction and 23.8% reported an increase in weekly alcohol consumption. Compared to individuals that did not alter their drinking behaviour, both increased and reduced alcohol consumption during lockdown was associated with poorer mood and higher stress levels. Increased alcohol consumption was associated with significantly reduced perceived immune fitness and a high presence and severity of COVID-19 symptoms. This effect was not significant among individuals with reduced or unaltered alcohol consumption.

Background: Resistance to alcohol hangover may be a risk factor for alcohol use disorder. Previous research to establish the prevalence of hangover resistance in a drinking population has either not used comparable intoxication levels or has considered hangover resistance over a limited time frame. The purpose of this study was to examine the prevalence of lifetime hangover negative (LHN) drinkers across comparable eBAC values ranging from 0 to 500 mg/dl. Methods: Students at an eastern Canadian university were surveyed about their heaviest drinking episode in the past month and indicated whether they had ever experienced a hangover in their lifetime (LHN) and, if they had, the hangover severity they experienced the next day. eBACs were calculated and the percentage of LHN drinkers was computed at each 10 mg/dl eBAC increment from 0 to 500 mg/dl. Results: Most LHN drinkers (58% female, 71% male) had an eBAC on their heaviest drinking occasion below 80 mg/dl. Above eBACs of 80 mg/dl, 5.8% of female and 5.1% of male drinkers were lifetime hangover negative. Conclusions: The results suggest that only a small percentage of heavy drinkers lay claim to being lifetime hangover negative.

Alcohol hangover is associated with the development of alcohol use disorders, yet few studies have examined the influence of hangover on cognitive processes that may contribute towards future alcohol consumption such as response inhibition and attentional bias towards alcohol-related stimuli. Therefore, the current study aimed to explore the effects of hangover on these processes. In total, 37 adult drinkers who reported regularly engaging in heavy episodic drinking and experiencing a hangover at least once in the previous month took part in this within-subjects, “naturalistic” crossover study. Participants completed Go/No-Go (assessing response inhibition) and Visual Dot Probe (attentional bias) tasks in a hangover condition (morning following alcohol consumption) and a no-hangover condition (no alcohol consumption for at least 24 h). Participants also completed measures of hangover severity, mood, and perceived mental effort. Results indicated impaired response inhibition during hangover compared to the no-hangover condition (p < 0.001, d = 0.89), but no difference in attentional bias scores between conditions. Participants reported expending greater mental effort to complete tasks (p < 0.001, d = 1.65), decreased alertness (p < 0.001, d = 3.19), and reduced feelings of tranquillity (p < 0.001, d = 1.49) in the hangover versus no-hangover condition. Together, these findings suggest that alcohol hangover is associated with impaired response inhibition and lower mood. However, problems with recording eye-tracking data on the Visual Dot Probe task used in the present study may limit the reliability of our attentional bias findings.

The limited number of available studies that examined the pathology of alcohol hangover focused on biomarkers of alcohol metabolism, oxidative stress and the inflammatory response to alcohol as potentially important determinants of hangover severity. The available literature on alcohol metabolism and oxidative stress is reviewed in this article. The current body of evidence suggests a direct relationship between blood ethanol concentration and hangover severity, whereas this association is not significant for acetaldehyde. The rate of alcohol metabolism seems to be an important determinant of hangover severity. That is, fast elimination of ethanol is associated with experiencing less severe hangovers. An explanation for this observation may be the fact that ethanol—in contrast to acetaldehyde—is capable of crossing the blood–brain barrier. With slower ethanol metabolism, more ethanol is able to reach the brain and elicit hangover symptoms. Hangover severity was also significantly associated with biomarkers of oxidative stress. More oxidative stress in the first hours after alcohol consumption was associated with less severe next-day hangovers (i.e., a significant negative correlation was found between hangover severity and malondialdehyde). On the contrary, more oxidative stress at a later stage after alcohol consumption was associated with having more severe next-day hangovers (i.e., a significant positive correlation was found between hangover severity and 8-isoprostane). In conclusion, assessment of biomarkers of alcohol metabolism suggests that fast elimination of ethanol is associated with experiencing less severe hangovers. More research is needed to further examine the complex interrelationship between alcohol metabolism, the role of acetaldehyde and oxidative stress and antioxidants, and the pathology of the alcohol hangover.

The aim of this study was to investigate whether baseline mood and/or mood while drinking have an impact on alcohol hangover severity. A survey was held among N = 331 young adults (mean age = 23.6 years, range = 18–35 years). Demographics, alcohol consumption, subjective intoxication, and hangover severity were assessed for the past three days. In addition, mood (baseline, while drinking, and during hangover) was also assessed. N = 143 participants reported to be hungover on the day of assessment, N = 122 participants reported to have been hungover the previous day (‘yesterday’), and N = 87 participants reported to have been hungover two days before the assessment (‘2 days ago’). The analyses revealed that baseline mood and mood while drinking had no relevant effect on the amount of consumed alcohol and did not significantly contribute to hangover severity. However, hangover severity was associated with significantly increased negative affect, particularly with higher levels of subjective stress on the day of the hangover.

Hangover resistance may be linked to an increased risk of continuing harmful drinking behaviours as well as involvement in potentially dangerous daily activities such as driving while hungover, mainly due to the absence of negative consequences (i.e., hangover symptoms) the day after alcohol consumption. The aim of this study was to examine the occurrence of claimed alcohol hangover resistance relative to estimated blood alcohol concentration (eBAC). A total of 1198 participants completed an online survey by answering questions regarding their demographics, alcohol consumption and occurrence of hangover. Two methods were used to calculate eBAC, one based on the modified Widmark Equation (N = 955) and the other from an equation averaging the total body water (TBW) estimates of Forrest, Watson, Seidl, Widmark and Ulrich (males only) (N = 942). The percentage of participants who claimed to be hangover resistant decreased rapidly with increasing eBAC and only a small number of hangover resistant drinkers remained at higher eBACs. Comparisons of the eBACs calculated by the two methods revealed significantly higher BACs when using the modified Widmark equation. These findings suggest that additional research for eBAC calculations is needed to improve accuracy and comprehensiveness of these equations for future alcohol hangover research.

An increasing number of studies are focusing on the inflammatory response to alcohol as a potentially important determinant of hangover severity. In this article, data from two studies were re-evaluated to investigate the relationship between hangover severity and relevant biomarkers of alcohol metabolism, oxidative stress and the inflammatory response to alcohol. Hangover severity was significantly and positively correlated with blood concentrations of biomarkers of the inflammatory response to alcohol, in particular, Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and C-reactive protein (CRP). At 4 h after alcohol consumption, blood ethanol concentration (but not acetaldehyde) was significantly and positively associated with elevated levels of IL-6, suggesting a direct inflammatory effect of ethanol. In addition, biomarkers of oxidative stress, i.e., malondialdehyde and 8-isoprostrane, were significantly correlated with hangover severity, suggesting that oxidative stress also contributes to the inflammatory response. The timing of the assessments suggests initial slow elimination of ethanol in the first hours after alcohol consumption. As a consequence, more ethanol is present in the second half of the night and the next morning, which will elicit more oxidative stress and a more profound inflammatory response. Together, these processes result in more severe hangovers.

Driving is increasing across the world and road traffic accidents are a major cause of serious injuries and fatalities. The link between alcohol consumption and impaired driving has long been established and has led to legislation in many countries, with enforcement of legal limits based on blood alcohol concentration levels. Alcohol hangover research is an emerging field with a range of laboratory and naturalistic studies now clearly demonstrating the significant impairments that can result from hangover, even when alcohol levels are measured at or close to zero the day following a social drinking occasion. Driving is a commonplace activity but requires competency with a range of complex and potentially demanding tasks. Driving impaired can have serious consequences, including death and serious injury. There have been only limited alcohol hangover driving studies. The studies presented examined the consequences of alcohol hangover with a driving simulator contrasting a group with zero residual alcohol (N = 26) next day and another with residual alcohol (N = 26) assessed with breathalyzer in the morning before undertaking a 20 min commute to work. All participants completed a morning drive after a night without alcohol consumption and another after a night of social drinking. The driving scenarios were relatively demanding including traffic and pedestrians, traffic lights and other potential hazards in a mixed rural and urban journey. Subjective hangover and workload were assessed in addition to a range of driving performance variables, including divided attention, steering control and driving violations. Analyses contrasted driving in the no alcohol condition with the residual alcohol condition. The combined groups data (N = 52) was contrasted with the zero and residual alcohol groups. Significant contrasts were found for a range of driving measures, including divided attention, vehicle control, and driving violations as well as perceived workload. The pattern of impairment was broadly similar across both groups, indicating that whether or not residual alcohol was present, consistent driving impairment was seen. The relatively high number of significant variables may reflect the increased cognitive demand of the 20 min commute drive including busy and complex urban environments. This was also reflected in the significant increase in perceived workload recorded across the 6 dimensions of the National Aeronautics and Space Administration Task Load Index (NASA-TLX). Associations between subjective measures and driving performance with hangover suggested a potential lack of awareness of impairment, though were limited in number. The overall findings indicate that the levels of impairment seen reflect those seen with alcohol impaired driving, even when breath alcohol is zero.

The current study evaluated the next day consequences of a social night of drinking compared to a no alcohol night, with standardised mood and portable screen-based performance measures assessed in the morning at participants’ homes, and a breathalyser screen for zero alcohol. A mixed sex group (n = 20) took part in the study. Participants reported consuming on average 16.9 units (135 g) alcohol, resulting in a hangover rating of 60 (out of 100) compared to 0.3 following the no alcohol night. Statistical significance comparisons contrasting the hangover with the no alcohol condition revealed an increase in negative mood and irritability during hangover and an (unexpected) increase in risk and thrill seeking. Performance scores showed an overall slowing of responses across measures, but with less impact on errors. The results support the description of hangover as a general state of cognitive impairment, reflected in slower responses and reduced accuracy across a variety of measures of cognitive function. This suggests a general level of impairment due to hangover, as well as increased negative mood. The use of a naturalistic design enabled the impact of more typical levels of alcohol associated with real life social consumption to be assessed, revealing wide ranging neurocognitive impairment with these higher doses. This study has successfully demonstrated the sensitivity of home-based assessment of the impact of alcohol hangover on a range of subjective and objective measures. The observed impairments, which may significantly impair daily activities such as driving a car or job performance, should be further investigated and taken into account by policy makers.

Recent research has suggested that processes reliant on executive functions are impaired by an alcohol hangover, yet few studies have investigated the effect of hangovers on core executive function processes. Therefore, the current study investigated the effect of hangovers on the three core components of the unity/diversity model of executive functions: the ability to switch attention, update information in working memory, and maintain goals. Thirty-five 18-to-30-year-old non-smoking individuals who reported experiencing a hangover at least once in the previous month participated in this study. They completed tasks measuring switching (number-switching task), updating (n-back task), and goal maintenance (AX Continuous Performance Test, AX-CPT) whilst experiencing a hangover and without a hangover in a ‘naturalistic’ within-subjects crossover design. Participants made more errors in the switching task (p = 0.019), more errors in both the 1- (p < 0.001) and 2-back (p < 0.001) versions of the n-back, and more errors in the AX-CPT (p = 0.007) tasks when experiencing a hangover, compared to the no-hangover condition. These results suggest that an alcohol hangover impairs core executive function processes that are important for everyday behaviours, such as decision-making, planning, and mental flexibility.

In 2016, the Alcohol Hangover Research Group defined the alcohol hangover as “the combination of mental and physical symptoms experienced the day after a single episode of heavy drinking, starting when blood alcohol concentration (BAC) approaches zero”. In the light of new findings and evidence, we carefully reviewed the different components of that definition. Several studies demonstrated that alcohol hangovers are not limited to heavy drinking occasions. Instead, data from both student and non-student samples revealed that at a group level, alcohol hangover may occur at much lower BAC levels than previously thought. Regression analysis further revealed that for individual drinkers, the occurrence of hangovers is more likely when subjects consume more alcohol than they usually do. However, hangovers may also occur at a drinker’s usual BAC, and in some cases even at lower BAC (e.g. in case of illness). We also carefully reviewed and modified other parts of the definition. Finally, hangovers are not necessarily limited to the ‘next day’. They can start at any time of day or night, whenever BAC approaches zero after a single dinking occasion. This may also be on the same day as the drinking occasion (e.g. when drinking in, or until the morning and subsequently having a hangover in the afternoon or evening). To better reflect the new insights and sharpen the description of the concept, we hereby propose to update the definition of the alcohol hangover as follows: “The alcohol hangover refers to the combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero”, and recommend to use this new definition in future hangover research.

The hangover is the most commonly reported negative consequence of alcohol use with several studies reporting the detrimental consequences of hangover on health, economy, and society. Research has emphasized the socioeconomic consequences of experiencing these physical and psychological symptoms in relation to absenteeism, increased risk of having accidents and injuries, and impairment of daily activities, such as job performance and driving a car. During the 10th Alcohol Hangover Research Group meeting, held on 29 April 2018, in Utrecht, The Netherlands, aspects of alcohol hangover were presented with regards to determinants, biological and cognitive consequences and potential treatments. Precursory and posterior factors influencing alcohol hangover, including biological, psychological, behavioral, metabolic aspects, cognitive functioning, and the role of the immune system in the development of alcohol hangover, were presented. In addition, potential preventive measures and treatments of alcohol hangover to reduce the adverse consequences of alcohol consumption and hangover symptoms were discussed. One study revealed that an average of 24% of social and heavy drinkers claimed not to experience hangover symptoms across time. Another study showed that food intake (either healthy or junk food) had no significant impact on next-day hangover severity. Research examining cognitive and psychomotor functioning during hangover revealed impairments in collective problem solving and response inhibition, but not attentional bias towards alcohol-related cues. The alcohol hangover state further significantly impaired driving performance, even for a short commute to work. With regard to the pathology of the alcohol hangover, research was presented that demonstrated increases in saliva cytokine concentrations confirming drinking alcohol and the hangover phase are both associated with an immune response. Other presentations discussed that scientific literature shows that there are no effective hangover treatments available yet. However, although promising, new hangover treatments are currently in development. Taken together, at the 10th Alcohol Hangover Research Group meeting, a comprehensive overview of the causes, consequences, and potential treatments of the alcohol hangover was presented.

The present proceedings offer a summary of the 11th meeting of the Alcohol Hangover Research Group held in April 2019 in Nadi, Fiji. The aim of the meeting was to gather the world’s leading experts in the field of alcohol hangover and share advances and ideas to help better understand the underlying pathology, consequences, and potential therapeutics. Several aspects of alcohol hangover research were discussed, including hangover-associated impairments of cognitive performance and health, novel and best research practice, the validation and use of wearable technology and online tools for off-site data collection, effects of hangover on physical strength performance, new evidence on sex differences in the occurrence and severity of alcohol hangover, and exciting future projects and directions.

Studies assessing alcohol mixed with energy drink (AMED) use and drinking behaviors have been largely restricted to student-only cohorts. Thus, it is not known whether evidence from these studies is applicable to non-student populations. This study examined alcohol consumption and involvement in negative alcohol-related consequences among AMED and alcohol-only (AO) users, with the aim of determining whether drinking behaviors differ according to student status. An online survey was conducted in Australia to assess alcohol consumption and alcohol-related consequences following AMED and AO consumption, according to student status. The final sample consisted of 1369 participants. Between-subjects analyses comparing AMED and AO users, confirmed previous findings in that, compared with AO users, AMED users consumed significantly more alcohol, consumed alcohol more frequently and were involved in a greater number of alcohol-related consequences. Within-subjects analyses of AMED users comparing AMED and AO drinking occasions revealed that significantly less alcohol was consumed and involvement in negative alcohol-related consequences was lower during AMED compared with AO drinking occasions. Regardless of drink type, compared with students, non-students consumed more alcohol, consumed alcohol more frequently and were involved in a greater number of negative alcohol-related consequences. These findings provide further evidence that AMED use is one manifestation of a risk-taking personality and suggest that non-students drink more alcohol, drink more frequently and are involved in a greater number of negative alcohol-related consequences than students.

The 2010 Alcohol Hangover Research Group consensus paper defined a cutoff blood alcohol concentration (BAC) of 0.11% as a toxicological threshold indicating that sufficient alcohol had been consumed to develop a hangover. The cutoff was based on previous research and applied mostly in studies comprising student samples. Previously, we showed that sensitivity to hangovers depends on (estimated) BAC during acute intoxication, with a greater percentage of drinkers reporting hangovers at higher BAC levels. However, a substantial number of participants also reported hangovers at comparatively lower BAC levels. This calls the suitability of the 0.11% threshold into question. Recent research has shown that subjective intoxication, i.e., the level of severity of reported drunkenness, and not BAC, is the most important determinant of hangover severity. Non-student samples often have a much lower alcohol intake compared to student samples, and overall BACs often remain below 0.11%. Despite these lower BACs, many non-student participants report having a hangover, especially when their subjective intoxication levels are high. This may be the case when alcohol consumption on the drinking occasion that results in a hangover significantly exceeds their “normal” drinking level, irrespective of whether they meet the 0.11% threshold in any of these conditions. Whereas consumers may have relative tolerance to the adverse effects at their “regular” drinking level, considerably higher alcohol intake—irrespective of the absolute amount—may consequentially result in a next-day hangover. Taken together, these findings suggest that the 0.11% threshold value as a criterion for having a hangover should be abandoned.

Although hangover is a common consequence of heavy alcohol consumption, the area is heavily under-researched. Hangover frequency is a potential predictor of future alcohol use disorder that may be affected by hangover severity, yet the relationship between hangover frequency and severity has not been investigated. Using different methodologies and assessment instruments, two surveys, and one naturalistic study collected data on hangover frequency, hangover severity, and alcohol consumption. The relationship between hangover frequency and severity was investigated via correlational analysis, considering potentially moderating variables including alcohol intake, estimated blood alcohol concentration, demographics, and personality characteristics. In all the three studies, a positive and significant association between hangover frequency and severity was found, which remained significant after correcting for alcohol intake and other moderating factors. These findings suggest that hangover severity increases when hangovers are experienced more frequently and may be driven by sensitization or reverse tolerance to this aspect of alcohol consumption. Future research should further investigate the relationship between hangover frequency and severity and alcohol use disorder and its implications for prevention.

Several dietary components have been shown to influence alcohol metabolism and thereby potentially affect the development of a hangover. From the literature, it is evident that dietary nicotinic acid and zinc play a pivotal role in the oxidation of ethanol into acetaldehyde. The aim of the current study was to associate dietary intake of nicotinic acid and zinc with hangover severity. To this end, data from n = 23 healthy social drinkers who participated in a naturalistic hangover study were analyzed. n = 10 of them reported to be hangover-resistant (the control group), whereas n = 13 reported to have regular hangovers (the hangover-sensitive group). Two 24 h dietary recall records were completed, one for the day of alcohol consumption and another one for an alcohol-free control day. Dietary nutrient intake was averaged and did not significantly differ between hangover-sensitive and hangover-resistant drinkers. For the hangover-sensitive drinkers, partial correlations with overall hangover severity were computed, controlling for estimated blood alcohol concentration. A bootstrapping technique was applied to account for the relatively small sample size. The results showed that dietary intake of nicotinic acid (rPB = −0.521) and zinc (rPB = −0.341) were significantly and negatively associated (p < 0.002) with overall hangover severity. Dietary zinc intake was also significantly and negatively associated with severity of vomiting (rPB = −0.577, p < 0.002). No significant associations with hangover severity were found for other nutrients, such as fat and fibers. In conclusion, this study suggests that social drinkers who have a higher dietary intake of nicotinic acid and zinc report significantly less severe hangovers. As hangover-resistant and hangover-sensitive drinkers had a similar dietary nutrient intake, the claim of being hangover-resistant must be based on other unknown biopsychosocial factors. These findings should be replicated in a larger sample and include more elaborate food frequency questionnaires or nutrient-specific dietary intake records for zinc and nicotinic acid, and preferably accompanied by nutrient assessments in urine and/or blood.

Studies have demonstrated significant sex differences in alcohol intoxication effects. In contrast, the majority of studies on the alcohol hangover phase did not investigate sex differences. Therefore, the current study examined possible sex differences in the presence and severity of alcohol hangover symptoms. Data from n = 2446 Dutch students (male = 50.7%, female = 49.3%) were analyzed. They reported the presence and severity of 22 hangover symptoms experienced after their past month heaviest drinking occasion. Subjects were categorized according to their estimated peak blood alcohol concentration (eBAC) and presence and severity of the hangover symptoms were compared between men and women. In the lowest eBAC group (0% ≤ eBAC < 0.08%), no significant sex differences were found. In the subsequent eBAC group (0.08% ≤ eBAC < 0.11%), severity of nausea was significantly higher in women than in men. In the third eBAC group (0.11% ≤ eBAC < 0.2%), women reported higher severity scores on nausea, tiredness, weakness, and dizziness than men. Men reported the presence of confusion significantly more often than women, and women reported the presence of shivering significantly more often than men. In the fourth eBAC group (0.2% ≤ eBAC < 0.3%), women reported higher severity scores on nausea and tiredness than men. In the highest eBAC group (0.3% ≤ eBAC < 0.4%), no significant sex differences were found. In conclusion, across the eBAC groups, severity scores of nausea and tiredness were higher in women than in men. However, albeit statistically significant, the observed sex differences in presence and severity of hangover symptoms were of small magnitude, and therefore, have little clinical relevance.

Alcohol consumption can negatively affect sleep quality. The current study examined the impact of an evening of alcohol consumption on sleep, and next day activity levels and alcohol hangover. n = 25 healthy social drinkers participated in a naturalistic study, consisting of an alcohol and alcohol-free test day. On both days, a GENEactiv watch recorded sleep and wake, and corresponding activity levels. In addition, subjective assessments of sleep duration and quality were made, and hangover severity, and the amount of consumed alcoholic beverages were assessed. Alcohol consumption was also assessed in real-time during the drinking session, using smartphone technology. The results confirmed, by using both objective and subjective assessments, that consuming a large amount of alcohol has a negative impact on sleep, including a significant reduction in objective sleep efficiency and significantly lower self-reported sleep quality. Activity levels during the hangover day were significantly reduced compared to the alcohol-free control day. Of note, next-morning retrospective alcohol consumption assessments underestimated real-time beverage recordings. In conclusion, heavy alcohol consumption impairs sleep quality, which is associated with increased next day hangover severity and reduced activity levels. The outcome of this study underlines that, in addition to retrospectively reported data, real-time objective assessments are needed to fully understand the effects of heavy drinking.

Results from studies into the cognitive effects of alcohol hangover have been mixed. They also present methodological challenges, often relying on self-reports of alcohol consumption leading to hangover. The current study measured Breath Alcohol Concentration (BAC, which was obtained via breathalyzer) and self-reported drinking behavior during a night out. These were then related to hangover severity and cognitive function, measured over the internet in the same subjects, the following morning. Volunteers were breathalyzed and interviewed as they left the central entertainment district of an Australian state capital. They were provided with a unique identifier and, the following morning, logged on to a website. They completed a number of measures including an online version of the Alcohol Hangover Severity Scale (AHSS), questions regarding number and type of drinks consumed the previous night, and the eTMT-B-a validated, online analogue of the Trail Making Test B (TMT-B) of executive function and working memory. Hangover severity was significantly correlated with one measure only, namely the previous night’s Breath Alcohol Concentration (r = 0.228, p = 0.019). Completion time on the eTMT-B was significantly correlated with hangover severity (r = 0.245, p = 0.012), previous night’s BAC (r = 0.197, p = 0.041), and time spent dinking (r = 0.376, p < 0.001). These findings confirm that alcohol hangover negatively affects cognitive functioning and that poorer working memory and executive performance correlate with hangover severity. The results also support the utility and certain advantages of using online measures in hangover research.

Extensive research exists on relationships between psychological constructs and alcohol consumption. However, research on relationships with hangover severity remains limited. This study aimed to assess the associations between mental resilience, mood (i.e., depression, anxiety, and stress), coping, personality, and hangover severity. A total of N = 690 participants completed an online survey by answering questions regarding their demographics, alcohol use, hangover prevalence and severity, and several psychological assessments (Brief Resilience Scale, DASS-21, Brief Cope, and Brief Version of the Big Five Personality Inventory). Significant associations were found between hangover severity and mental resilience, mood, and avoidant coping. Higher levels of mental resilience were associated with less severe hangovers, whereas poorer mood was associated with more severe hangovers. No significant associations were found with personality traits. These findings demonstrate that several associations between psychological constructs and hangover severity exist and suggest a role of psychological factors in the pathology of the alcohol hangover. As our findings contrast with the results of previous studies that did not report an association between mental resilience and the presence and severity of hangovers, further research is warranted.

This study investigated immunological changes during an alcohol hangover, and the possible difference between hangover-resistant and hangover-sensitive drinkers in terms of immune reactivity. Using a semi-naturalistic design, N = 36 healthy social drinkers (18 to 30 years old) provided saliva samples on a control day (after drinking no alcohol) and on a post-alcohol day. Hangover severity was rated directly after saliva collection. Cytokine concentrations, interleukin (IL)-1β, IL-6, IL-8, IL-10 and tumor necrosis factor (TNF)-α, and hangover severity were compared between both test days and between hangover-sensitive and -resistant drinkers. Data from N = 35 drinkers (17 hangover-sensitive and 18 hangover-resistant) were included in the statistical analyses. Relative to the control day, there were significant increases in saliva IL-6 and IL-10 concentrations on the post-alcohol day. No significant differences in cytokine concentrations were found between hangover-sensitive and hangover-resistant drinkers, nor did any change in cytokine concentration correlate significantly with hangover severity. In line with previous controlled studies assessing cytokines in blood, the current naturalistic study using saliva samples also demonstrated that the immune system responds to high-level alcohol intake. However, further research is warranted, as, in contrast to previous findings in blood samples, changes in saliva cytokine concentrations did not differ significantly between hangover-sensitive and hangover-resistant drinkers, nor did they correlate significantly with hangover severity.

The aim of this study was to evaluate the efficacy of putative hangover treatment, Rapid Recovery, in mitigating alcohol hangover (AH) symptom severity. Using a double-blind, randomized, placebo-controlled, balanced crossover design, 20 participants attended the laboratory for two evenings of alcohol consumption, each followed by morning assessments of AH severity. Participants were administered Rapid Recovery and placebo on separate visits. In the first testing visit, participants self-administered alcoholic beverages of their choice, to a maximum of 1.3 g/kg alcohol. Drinking patterns were recorded and replicated in the second evening testing visit. In the morning visits, AH severity was assessed using questionnaires measuring AH symptom severity and sleep quality, computerized assessments of cognitive functioning as well as levels of blood biomarkers of liver function (gamma-glutamyl transferase (GGT)) and inflammation (high-sensitive C-reactive protein (hs-CRP)). There were no differences in the blood alcohol concentrations (BAC) obtained in the Rapid Recovery (mean = 0.096%) and placebo (mean = 0.097%) conditions. Participants reported significantly greater sleep problems in the Rapid Recovery compared to placebo condition, although this difference was no longer significant following Bonferroni’s correction. There were no other significant differences between Rapid Recovery and placebo. These data suggest that Rapid Recovery has no significant effect on alcohol hangover nor on associated biomarkers.