Most of us have been kept awake by pain, so it seems counterintuitive that a good dose of caffeine is just what the doctor ordered. However, a study by researchers at the University of Michigan finds that administering caffeine before surgery can block an increase in pain caused by sleep deprivation.

Sleep-deprived patients are likely to be in acute and longer-lasting pain after surgery than those who get a good night’s sleep. But researchers think caffeine may help to counteract the negative impact of sleep loss on post-op pain.

In the study, researchers conducted experiments on multiple groups of rats, including those that were deprived of sleep before surgery, and those that were allowed to sleep for six hours before surgery. In two of the experiments, each rat received an injection of caffeine before receiving a surgical incision. The rats were evaluated daily to measure the effects on post-operative pain for the next six days.

Results showed that the sleep-deprived rats were much more sensitive to pain following surgery and took longer to recover compared with rats that were permitted to sleep before the procedure. Researchers noted that the caffeine injections blocked the receptors for adenosine — a neurotransmitter that plays a key role in regulating sleep — thereby reducing the effects of sleep deprivation on post-op pain.

And while the scientists say more research is needed, a good night’s sleep before surgery could go a long way in recovery afterward. And coffee always seems like a good idea.