Drinking too much alcohol appears to interfere with a surgeon’s skills even into the next day, according to a study that used a virtual reality simulator to test the theory.

Medical News Today reports that researchers in Ireland studied 16 university science students and eight surgeons. At the beginning of the study, all participants were tested on their surgical skills using the virtual reality simulator. The students were then randomly assigned to drink as much as they wanted or to not drink any alcohol. All of the surgeons were told to drink as much as they wanted. All participants then performed tests of simulated surgery the next day at 9 a.m., 1 p.m. and 4 p.m.

The nondrinking students showed no changes in performance, while students in the alcohol group performed worse. The surgeons also performed worse overall after they had been drinking.

Writing in the Archives of Surgery, the researchers say that, “Excessive consumption of alcohol appeared to degrade surgical performance the following day even at 4 p.m., suggesting the need to define recommendations regarding alcohol consumption the night before assuming clinical surgical responsibilities.”