Why daytime wounds heal faster than those that happen at night

Science has just given us another reason to sleep the night away.

Researchers in England have discovered that wounds suffered during the day heal faster than those that are inflicted at night. It sounds bizarre, but apparently the secret lies with your body’s internal clock. Skin cells known as fibroblasts, which are key to healing cuts and scrapes, are more active during the hours in which you are normally awake.

A team of scientists from the Medical Research Council’s Laboratory of Molecular Biology in Cambridge studied the behavior of fibroblasts. They’d hoped to see how the cells’ behavior changed depending on the time of day.

Their research, which was published last month in Science’s Translational Medicine journal, found that just an eight-hour difference in the time a cut occurred could have a big effect on the healing process.

The team initially ran tests on wounded cells grown in petri dishes.

“You can see by eye … the [daytime] wounded ones take off and the [nighttime] one drags,” biologist John O’Neill told Science.

O’Neill’s team then tested their theory on mice and the results “astonished” them. They showed about twice as many fibroblasts moved to a mouse’s wound during daytime hours as compared to nighttime.

After checking data from the International Burn Injury Database, the scientists found that human wounds are also affected by timing. The team found that burns suffered at night took about 11 days longer to heal than similar burns that were suffered during the day. If you get a burn during the day, healing takes about 17 days, versus 28 days for an overnight burn.

The team hopes its research can deepen our understanding of the body’s internal clock and how it affects humans (you know, besides making you insanely tired at 2 p.m. every day for some reason).