Alcohol Hangover Research Group
The Alcohol Hangover
Published as: Verster JC. The alcohol hangover: a puzzling phenomenon. Alcohol &
Alcoholism 2008, 43: 1-
Many people favour the (unproven) popular belief that dehydration is the main cause
of alcohol hangover symptoms. However, taking a closer look at the present research
on biological changes during alcohol hangovers suggests otherwise. A limited number
of experiments have studied biological changes that are present the day after excessive
drinking (for a review, see Ylikahri and Huttunen, 1977). Significant changes were
reported on endocrine parameters (increased concentrations of vasopressin, aldosterone,
and renin) and metabolic acidosis (reduced blood pH values due to increased concentrations
of lactate, ketone bodies, and free fatty acids). These effects are related to dehydration
and cause symptoms such as dry mouth and thirst. In addition, changes in immune system
parameters (increased concentrations of pro-
The first line of evidence for the hypothesis that effects of immune activity on
the CNS may be the cause of alcohol hangover comes from studies showing that cytokines
communicate with the brain. The nervus vagus pathway is the main afferent pathway
mediating the effects of peripherally released cytokines in the CNS (Dantzer et al.,
1998). Peripherally released cytokines thus have central effects, by signaling the
brain to up-
Second, the effects caused by cytokines are very similar to the core symptoms of
alcohol hangover, suggesting that underlying processes might be the same. Cerebral
cytokines (IL-
Third, in humans, a relationship between the presence of cytokines and memory impairment
has been demonstrated (Reichenberg et al., 2001). Endotoxin, injected to provoke
sickness behaviour in healthy volunteers significantly increased cytokine concentrations
(IL–1ß, IL-
There have been a few studies that proposed that dehydration itself is a cause of memory impairment (e.g. Cian et al., 2001; Tomporowski, 2003; Lieberman et al., 2005). However, intense stressors (e.g. simulated combat or heavy prolonged exercise) were used to cause dehydration. Hence, it can be argued that these stressors have mobilized the immune system that in return causes memory impairment, independent of the dehydration effects that accompany these stressors. In support for this idea, in passive circumstances without a stressor (e.g. using abstinence from water for 11 h) no significant effects were reported on tests examining memory functions (Neave et al., 2001). Thus, these findings support the hypothesis that not dehydration, but a stressor causes an immune response which results in memory problems. Future research should verify this hypothesis.
In this issue of Alcohol & Alcoholism, the article by Stephens and colleagues clearly
discusses the difficulties and pitfalls of hangover research. Hangover research showed
conflicting results: half the studies report significant performance effects whereas
the other half do not. The most important cause of this is the fact that the pathology
of alcohol hangover has not been elucidated. This is illustrated by the fact that
whereas numerous hangover cures are available, only few of them are scientifically
investigated and none of them prevents or relieves hangovers in a significant way
(Pittler et al., 2005). Since the biology of hangovers is not well understood, it
is not surprising that the design of experiments and the included psychological tests
lack an evidence-
Blinding, i.e. preventing participants from knowing which is the hangover or placebo
test day, is especially difficult in alcohol hangover research. Considerable amounts
of alcohol (> 1.0 g/kg) need to be consumed to produce a hangover. Alcohol intoxication
and its after-
As pointed out by Stephens and colleagues, the small sample size of many hangover experiments is another issue that resulted in conflicting results. Several studies tested less than 10 subjects, and thus, do not have enough statistical power to draw strong conclusions from the outcome measures. Moreover, in most studies only young healthy men participated. It is well known that men and women differ in alcohol metabolism, and thus, may differ in the presence and severity of hangover symptoms. More recent studies (Verster et al., 2003; McKinney et al., 2004) acknowledged this and did use larger groups of subjects consisting of both men and women.
To make matters complicated, the presence and severity of alcohol hangovers is influenced
by many factors other than the amount of alcohol. One is these factors is the presence
of congeners in alcoholic drinks. Congeners are substances that flavour and colour
drinks. In laboratory experiments mixing pure alcohol with orange juice can prevent
the presence of congeners. However, in real life (and naturalistic experiments) people
consume a variety of different alcoholic drinks which all have different congener
content. Stephens and colleagues shortly discuss the impact of congeners on performance
measures during alcohol hangover, but acknowledge that not much research has been
done in this area. As summarized in Figure 1, it can be concluded that alcoholic
drinks that contain more congeners produce more severe alcohol hangovers. Moreover,
a recent survey showed it takes fewer high-
Fig. 1 Number of drinks that produce a hangover and the reported corresponding hangover
severity for beer, wine and liquor.Hangover severity ranges from 0 (no hangover)
to 8 (extreme hangover). Significant differences (P < 0.05) are indicated by *. Note:
In The Netherlands a standardized drink of beer, wine or liquor all contain the same
amount of alcohol.
A second factor that is often not incorporated in research is the effect of sleep
duration and quality on the hangover state. Whereas in laboratory studies participants
are often allowed a full night of sleep, in real life drinking time often goes at
the expense of sleep time. The results of a recent survey, summarized in Figure 2,
show that some of the symptoms that are experienced the day after excessive drinking
are significantly related to sleep duration and quality and not to the amount of
alcohol that was consumed (Verster and Roehrs, 2007). The resulting daytime sleepiness
is significantly related to several affects that are generally ascribed to be alcohol
hangover symptoms.
Fig. 2 Schematic representation of the relationship between individual hangover
symptoms and sleep quality, daytime sleepiness and alcohol quantity. Please note
that only alcohol quantity and daytime sleepiness correlated significantly with overall
hangover severity. All depicted correlations were significant (P < 0.05), except
vomiting (P < 0.06) and guilt (P < 0.07).
The results from this survey underline the fact that many factors influence the hangover
state. On the other hand, it is essential to keep in mind that several factors co-
Although there are many methodological shortcomings in alcohol hangover research,
it is evident that alcohol hangovers do have an impact on daily activities such as
on-
They conducted structured interviews among 800 assembly workers in order to examine
the relationship between hangovers and work-
Interestingly, no significant differences were found in absenteeism between workers reporting hangovers and those who did not. A possible explanation may be that workers with a hangover feel that having a hangover is ‘their own fault’, and the obligation they have to go to work may prevent calling sick. The fact that workers do go to work when having a hangover is of concern, especially since some in jobs making the wrong decisions may have serious consequences.
The article by Stephens and colleagues calls for additional hangover research, using
more sophisticated research methods. In this context, researchers should ask themselves
the question ‘what is the alcohol hangover?’. It is evident that besides the alcohol
amount many other factors play a role in determining the presence and severity of
hangovers. To complicate matters, co-
References
Ames G. M., Grube J. W., Moore R. S. The relationship of drinking and hangovers to workplace problems: an empirical study. Journal of Studies on Alcohol (1997) 58:37–47.
Cian C., Barraud P. A., Melin B., et al. Effects of fluid ingestion on cognitive
function after heat stress or exercise-
Dantzer R., Bluthe R.-
Kim D.-
Lieberman H. R., Bathalon G. P., Falco C. M., et al. Severe decrements in cognition function and mood induced by sleep loss, heat, dehydration, and undernutrition during simulated combat. Biological Psychiatry (2005) 57:422–429.
Maier S. F. Bi-
Maier S. F., Watkins L. R. Cytokines for psychologists: implications of bidirectional
immuno-
McKinney A, Coyle K. Next day effects of a normal night's drinking on memory and psychomotor performance. Alcohol Alcohol (2004) 39:509–513.
Neave N., Scholey A. B., Emmett J. R., et al. Water ingestion improves subjective alertness, but has no effect on cognitive performance in dehydrated healthy young volunteers. Appetite (2001) 37:255–256.
Parnet P., Amindari S., Wu C., et al. Expression of type I and type II interleukin-
Pittler M. H., Verster J. C., Ernst E. Interventions for preventing or treating alcohol hangover: systematic review of randomized trials. British Medical Journal (2005) 331:1515–1518.
Reichenberg A., Yirmiya R., Schuld A., et al. Cytokine-
Stephens R., Ling J., Heffernan T.M., Heather N., Jones K. A review of literature
on the cognitive effects of alcohol hangover. Alcohol and alcoholism (2008) 43: 163-
Tomporowski P. D. Effects of acute bouts of exercise on cognition. Acta Psychologica (2003) 112:297–324.
Verster J. C. Congeners and alcohol hangover: differences in severity among Dutch college students after consuming beer, wine or liquor. Alcoholism: Clinical and Experimental Research (2006) 30(Suppl. 6):53A.
Verster J. C., Roehrs T. Sleep after an evening of heavy drinking and its impact on daytime sleepiness and alcohol hangover severity. Sleep and Biological Rhythms (2007) 5(Suppl. 1):A18.
Verster J. C., van Duin D., Volkerts E. R., et al. Alcohol hangover effects on memory functioning and vigilance performance after an evening of binge drinking. Neuropsychopharmacol (2003) 28(4):740–746.
Ylikahri R. H., Huttunen M. O. Metabolic and endocrine pathology during hangover. Advances in Experimental Medicine and Biology (1977) 85B:423–442.
The alcohol hangover develops when blood alcohol concentration (BAC) returns to zero
and is characterized by a feeling of general misery that may last more than 24 h.
It comprises a variety of symptoms including drowsiness, concentration problems,
dry mouth, dizziness, gastro-
Although numerous scientific papers cover the acute effects of alcohol consumption, researchers largely neglected the issue of alcohol hangover. This lack of scientific interest is remarkable, since almost everybody is familiar with the unpleasant hangover effects that may
arise the day after an evening of excessive drinking, and with the
ways these symptoms may affect performance of planned activities.