It sounds like common sense, “Don’t drink before an operation,” right along with, “Don’t smoke before an operation.” But, not many people see it so. After reviewing multiple studies and cases, people who drink more than a few drinks a day are more susceptible to post-operative complications compared to someone who is considered to be a “light-drinker.”

From examining 55 different pre-op and post-op results within 30 days after surgery, it was shown that people who drank heavily were two times more likely to die a month after surgery, depending on which procedure and which complication, of course. Infections and wound-healing were amongst the common problems that occurred after surgery, says Marie Eliasene from the National Institute of Public Health at the University of Southern Denmark in Copenhagen and the author of this study.

80% of the patients in the study were more likely to have a difficulty in breathing, as well as 73% being more likely to contract an infection, and an additional 29% being admitted into the ICU, says Annals of Surgery. Alcohol diminishes the immune system, which is the majority of the reason for infections and troubles, and increases the risk of heavy bleeding.

Although doctors don’t advise you to refrain from drinking for a minimum of four weeks before surgery, it’s one of those things that really will improve your overall recovery.