Alcohol and caffeine

Alcohol helps you fall asleep but breaks up the second half of the night, and hangovers often bring anxiety. Caffeine can make you jittery, especially in large doses.

• Evidence: Some

Why it matters

Alcohol and sleep. A review of every known study on alcohol and sleep in healthy volunteers found the same pattern at all doses. People fell asleep faster and slept more deeply in the first half of the night, then slept worse in the second half [1]. Dream (REM) sleep started later and, at moderate and high doses, there was less of it overall.

Alcohol and the next day. The anxious, low feeling some people get the day after drinking has a nickname, “hangxiety”. A systematic review of 22 studies with over 6,000 people found hangovers were consistently linked to more anxiety and stress [2]. It was worse for people who tend to dwell on things or who were anxious to begin with. Most of these studies are surveys of young adults, so they show a link rather than measuring how big the effect is for you.

Caffeine and anxiety. In a meta-analysis of 14 studies with 546 healthy people, caffeine raised anxiety. The effect was moderate at lower doses and much larger at high doses, especially above 400 mg [6]. The US Food and Drug Administration says about 400 mg a day, roughly two to three 12-ounce cups of coffee, is not generally linked to harm for most adults. It also notes that some people are more sensitive, including during pregnancy and with some medicines [7].

How to do it

Alcohol

• Know the official numbers. The NHS advises no more than 14 units a week, spread over three or more days, with several drink-free days [3]. A pint of ordinary lager is about 2 units and a standard 175 ml glass of wine about 2.1. The 2025–2030 US Dietary Guidelines dropped their old daily drink limits and now simply say to drink less for better health [4].
• Stop earlier in the evening. If you drink, finishing a few hours before bed gives your body time to clear some of it before you sleep.
• Alternate drinks. Have water or a soft drink between alcoholic ones. It slows you down without making a big deal of it.
• Plan the morning after. After a big night, keep the next day light and don’t read too much into a gloomy mood.
• Try a month off, if you’re curious. In a survey of 857 British adults who signed up for Dry January, people were drinking less six months later, even those who didn’t finish the month. Very few drank more afterwards [5]. People who sign up are a self-selected group, so this can’t show the month itself caused the change.

Caffeine

• Count roughly. Coffee, energy drinks, strong tea and pre-workout powders add up.
• Cut back if you feel jittery or wired. Try a smaller cup, a half-caf, or tea instead of coffee before something stressful.
• Set an afternoon cutoff. Caffeine lasts for hours. sleepgood.now covers cutoff times for sleep.
• Reduce gradually. Dropping from several cups to none overnight often brings headaches and tiredness for a few days. Cut by one cup every few days instead.

Common mistakes

• Using a nightcap to sleep. It shortens the time to fall asleep and makes the second half of the night worse [1].
• Treating next-day anxiety as a sign something is wrong in your life. It may just be the drinks.
• Using coffee to cover a short night, then sleeping badly again because of the coffee.
• All-or-nothing rules that you drop after a week.

Evidence

Rated Some. The sleep findings come from many lab studies with consistent results, though the review was qualitative rather than a meta-analysis [1]. The hangover review shows a clear link, but most studies were surveys [2]. The caffeine meta-analysis is small and the studies varied a lot [6]. The Dry January study is observational [5].

Topics: Alcohol, Caffeine, Sleep, Anxiety, Foundations

Sources checked 4 October 2026. Spot a mistake? Tell us.