Hangovers Might Not Be From Alcohol Alone—Your Breathing Could Be to Blame
We usually chalk hangovers up to dehydration, poor sleep, or one drink too many. But what if one of the biggest reasons you feel awful the next morning isn’t just the alcohol itself—but how your body breathes to deal with it?
Emerging research and basic physiology suggest that low-grade hyperventilation—subtle over-breathing during and especially after drinking—could be a major contributor to hangover symptoms.
When the Liver Gets Overwhelmed, the Lungs Step In
The liver is your main detox organ, breaking down alcohol in a two-step process:
- Ethanol → Acetaldehyde (a toxic byproduct)
- Acetaldehyde → Acetate → CO₂ + Water
That final step produces carbon dioxide (CO₂), which is expelled through the lungs. CO₂ buildup in the blood stimulates the brainstem’s breathing center and drives the urge to take your next breath. Since alcohol is quickly absorbed, more CO₂ is produced—so drinking increases your breathing rate.
When you drink more than your liver can process, your lungs are recruited to assist. This isn’t just theory—breathalyzers measure alcohol in your exhaled breath, confirming the lungs' role in elimination.
To support this process, the body subtly shifts into faster, bigger, or mouth-based breathing—classic signs of low-grade hyperventilation.
The Tradeoff: Help With a Cost
This survival mechanism may help offload alcohol, but it comes with side effects. When you overbreathe, even slightly, CO₂ levels drop. This leads to narrow blood vessels and reduced oxygen delivery to the brain—mimicking classic hangover symptoms [ref1, ref2].
It also dehydrates you. A study found that we lose 42% more water when breathing through the mouth compared to the nose [ref3].
So yes, the lungs are trying to help—but in doing so, they may also be setting the stage for the headache, anxiety, and fatigue you wake up with the next day.
Champagne, Beer, and the Breathing Connection
This breath-alcohol connection works in both directions. It is widely believed that champagne is more intoxicating than wine—and for good reason. Carbonated beverages have been shown to speed up the emptying of the stomach into the small intestine, where alcohol is absorbed faster.
Drinks like champagne, beer, and whisky + soda aren't just carbonated for fun—the CO₂ they contain accelerates gastric emptying and alcohol absorption. [ref4, ref5] That's why fizzy drinks tend to hit faster.
Ever sipped a cold, bubbly beer and loved the crisp bite—only to return later to a flat, warm version that tastes dull? The alcohol content is the same, but without CO₂ absorption slows. The drink feels weaker, and the buzz is delayed. It’s not just about flavor—it’s about how your body processes it.
The reason bubbles speed things up comes down to digestion. The carbonation increases pressure in the stomach, stimulating the pyloric sphincter—a valve at the stomach’s base that opens to allow contents into the small intestine. That internal pressure causes the valve to open sooner, letting alcohol enter the bloodstream more quickly. In other words, bubbles don’t increase the amount of alcohol absorbed—they just deliver it faster.
Hangover Symptoms = Hyperventilation Symptoms
Let’s compare:
| Symptom | Hangover | Hyperventilation |
|---|---|---|
| Headache | ✅ | ✅ |
| Anxiety or uneasiness | ✅ | ✅ |
| Mood swings and irritability | ✅ | ✅ |
| Fatigue or brain fog | ✅ | ✅ |
| Dry mouth & dehydration | ✅ | ✅ |
| Dizziness or lightheadedness | ✅ | ✅ |
| Muscle aches or shakiness | ✅ | ✅ |
| Snoring & mouth breathing | ✅ | ✅ (strong signs) |
How to Recover Smarter (and Breathe Better)
The obvious way to avoid a hangover is, of course, not to drink at all. But if you're going to have that next drink and want to minimize the after-effect, don’t just hydrate—optimize your breathing:
- Breathe slowly through the nose (try “double out” breathing: exhale twice as long as you inhale)
- Sleep with your mouth closed—nasal strips or Sleep Tape can help
- Take a slow nasal “breath walk” the next day to restore balance
- Use a breath trainer like the Relaxator to improve CO₂ tolerance
- Hydrate steadily, but avoid chugging excess water
Final Thought: You Might Be Breathing Your Way Into a Hangover
The headache, restlessness, and next-day anxiety may not be just from alcohol—they could be from how your body tried to eliminate it. Snoring, dry mouth, and waking up too early? All signs that your breathing has gone into overdrive.
Next time, don’t just blame the booze or reach for water. Pay attention to your breath—it might be the missing link to waking up clear-headed and hangover-free.
Scientific References
Title: The Effects of altered arterial tensions of carbon dioxide and oxygen on cerebral blood flow and cerebral oxygen consumption of normal young men
Authors: Kety SS, Schmidt CF.
Journal: J Clin Invest. 1948 Jul;27(4):484-92. doi: 10.1172/JCI101995. PMID: 16695569; PMCID: PMC439519.
Link to full text: The Effects of altered arterial tensions of carbon dioxide and oxygen on cerebral blood flow and cerebral oxygen consumption of normal young men 
Abstract: A method for measuring quantitatively the volume of cerebral blood flow in man by inhalation of nitrous oxide (1) found its first application in a study of the cerebral circulatory effects of low CO2 tension achieved by hyperventilation; of high CO2 tension, and of high and low 02 tensions obtained by inhalation of appropriate gas mixtures (2). Only the first part of this study, the effects of active and passive hyperventilation, has been published in detail (3). The purpose of the present paper is to present the remainder of these findings and to derive from them, together with those of the hyperventilation experiments, evidence bearing on the intrinsic control of the human cerebral circulation as revealed by quantitative measurements.
Title: The influence of carbon dioxide on brain activity and metabolism in conscious humans
Authors: Xu F, Uh J, Brier MR, Hart J Jr, Yezhuvath US, Gu H, Yang Y, Lu H.
Journal: J Cereb Blood Flow Metab. 2011 Jan;31(1):58-67. doi: 10.1038/jcbfm.2010.153. Epub 2010 Sep 15. PMID: 20842164; PMCID: PMC3049465.
Link to full text: The influence of carbon dioxide on brain activity and metabolism in conscious humans
Abstract: A better understanding of carbon dioxide (CO(2)) effect on brain activity may have a profound impact on clinical studies using CO(2) manipulation to assess cerebrovascular reserve and on the use of hypercapnia as a means to calibrate functional magnetic resonance imaging (fMRI) signal. This study investigates how an increase in blood CO(2), via inhalation of 5% CO(2), may alter brain activity in humans. Dynamic measurement of brain metabolism revealed that mild hypercapnia resulted in a suppression of cerebral metabolic rate of oxygen (CMRO(2)) by 13.4% ± 2.3% (N=14) and, furthermore, the CMRO(2) change was proportional to the subject's end-tidal CO(2) (Et-CO(2)) change. When using functional connectivity MRI (fcMRI) to assess the changes in resting-state neural activity, it was found that hypercapnia resulted in a reduction in all fcMRI indices assessed including cluster volume, cross-correlation coefficient, and amplitude of the fcMRI signal in the default-mode network (DMN). The extent of the reduction was more pronounced than similar indices obtained in visual-evoked fMRI, suggesting a selective suppression effect on resting-state neural activity. Scalp electroencephalogram (EEG) studies comparing hypercapnia with normocapnia conditions showed a relative increase in low frequency power in the EEG spectra, suggesting that the brain is entering a low arousal state on CO(2) inhalation.
Title: Increased net water loss by oral compared to nasal expiration in healthy subjects
Authors: Svensson S, Olin AC, Hellgren J.
Journal: Rhinology. 2006 Mar;44(1):74-7. PMID: 16550955.
Link to full text: Increased net water loss by oral compared to nasal expiration in healthy subjects
Abstract:
Aim of the study: To compare the difference in respiratory water loss during expiration through the nose and through the mouth, in healthy subjects.
Methods: The study included 19 healthy, non-smoking volunteers without any present history of non-infectious rhinitis, presenting with symptoms of rhinitis, asthma or previous nasal surgery. Nasal and oral expiratory breath condensates were collected using a breath condenser during tidal respiration at indoor resting conditions. During the nasal breath condensate sampling, the subjects were breathing into a transparent face mask covering the nose and the mouth with the mouth closed. During the oral breath condensate sampling, the subjects inhaled through the nose and exhaled through a mouthpiece connected to the condenser. The airflow during the sampling was assessed with a dry-spirometer connected to the condenser. Sampling was stopped after 100 litres of expired air for each breathing mode. Nasal sampling was done before and after decongestion of the nasal mucosa with oxymetazoline, 0.5 mg/ml. The effect on the nasal mucosa was assessed with acoustic rhinometry.
Results: The mean loss of expired water was 42% less by nasal expiration before decongestion than by oral expiration (1.9 x 10(-3) g/L min compared to 2.7 x 10(-3) g/L min, p < 0.001). The mean expiratory minute ventilation was 9.0 L/min by nasal respiration and 9.8 L/min by oral respiration. Decongestion of the nasal mucosa showed a mean increase of the cross-sectional area at 4 cm from the nostril (1.44 to 1.67 cm2, p = 0.0024), but there was no effect on the net water loss (1.9 x 10(-3) g/Lmin vs 1.9 x 10(-3) g/Lmin).
Conclusion: This study showed that the net water loss increased by 42% when the breathing mode was switched from nasal to oral expiration during tidal breathing in healthy subjects. Increased water and energy loss by oral breathing could be a contributing factor to the symptoms seen in patients suffering from nasal obstruction.
Title: The effects of carbon dioxide in champagne on psychometric performance and blood-alcohol concentration
Authors: Ridout F, Gould S, Nunes C, Hindmarch I.
Journal: Alcohol Alcohol. 2003 Jul-Aug;38(4):381-5. doi: 10.1093/alcalc/agg092. PMID: 12814909.
Link to PubMed: The effects of carbon dioxide in champagne on psychometric performance and blood-alcohol concentration 
Abstract:
Aims: To assess the effects of carbon dioxide (CO(2)) in champagne on psychomotor performance and blood-alcohol concentration (BAC).
Methods: Twelve subjects consumed ethanol (0.6 g/kg body weight) served as champagne or champagne with the CO(2) removed, in a crossover study.
Results: Champagne produced significantly greater BACs and significantly increased reaction times in a divided attention task, than degassed champagne.
Conclusions: The CO(2) in champagne may accelerate absorption of alcohol, leading to more rapid or severe intoxication.
Title: Alcohol concentration and carbonation of drinks: the effect on blood alcohol levels
Authors: Roberts C, Robinson SP.
Journal: J Forensic Leg Med. 2007 Oct;14(7):398-405. doi: 10.1016/j.jflm.2006.12.010. Epub 2007 May 16. PMID: 17720590.
Link to PubMed: Alcohol concentration and carbonation of drinks: the effect on blood alcohol levels
Abstract: Alcohol absorption and elimination vary considerably amongst individuals, and are subject to influences from a variety of factors. The effects of alcohol concentration and beverage mixer type on the rate of alcohol absorption, in a controlled environment was studied. 21 subjects (12 male, 9 female) consumed a solution containing alcohol, on three separate occasions. The three solutions were, A: Neat vodka (37.5 vol%), B: Vodka mixed with still water (18.75 vol%), C: Vodka mixed with carbonated water (18.75 vol%). The volume of alcohol each subject consumed was determined by Widmark's equation. The alcohol was drunk in a 5 min period following an overnight fast and breath alcohol concentrations were measured over a 4h period using a breathalyser. 20/21 subjects absorbed the dilute alcohol at a faster rate than the concentrated alcohol. The difference between the absorption rates was found to be significant (p<0.001). The use of a carbonated mixer had varying effects on the alcohol absorption rate. 14/21 subjects absorbed the alcohol with the carbonated mixer at a faster rate, with 7 subjects showing either no change or a decrease in rate. The mean absorption rate for solution C was 4.39+/-0.45 (mg/100ml/min), and the difference between this absorption rate and that with the still mixer (1.08+0.36) was significant (p=0.006).
