A hangover is a collection of signs and symptoms linked to a recent bout of heavy drinking. A person with a hangover will usually experience a headache, feels sick, dizzy, sleepy, confused and thirsty. They can happen at any time of the day; however, they happen more commonly in the morning directly after a night of heavy drinking.
Aside from the physical symptoms, the person may experience elevated levels of anxiety, regret, shame, embarrassment and depression. The severity of a hangover is closely linked to how much alcohol was consumed, and whether the sufferer had enough sleep; the less sleep, the worse the hangover.
It’s impossible to really say how much alcohol can be safely consumed to avoid a hangover — it depends on the person and other factors, such as how tired they were before they even started drinking, whether they were already dehydrated before drinking started, whether they drank a lot of water during their drinking session, and how much sleep they got after.