Scientists have found that sleeping for an hour or more extra a night can dramatically improve an individual’s alertness and reduce their sensitivity to pain.

In fact, say the researchers, getting nearly 10 hours a night – rather than the recommended 8 – is more effective at reducing pain than taking the drug codeine.

The study used 18 healthy, pain-free volunteers who were randomly assigned either four nights of their normal sleep pattern or four nights of 10 hours in bed.

The American researchers measured daytime sleepiness using the multiple sleep latency test – a standard method used by doctors to diagnose sleep problems in which brain waves, eye movement, heart rate and muscle tone are measured.

Pain sensitivity was assessed using a heat source.

Results showed the extended sleep group slept 1.8 hours more per night than those on a regular sleeping pattern. This was associated with increased daytime alertness and significantly less pain sensitivity.

Those getting more sleep were able to keep their finger on a heat source for 25% longer, showing a loss of pain sensitivity.

Scientists have found that sleeping for an hour or more extra a night can dramatically improve an individual’s alertness and reduce their sensitivity to pain

The findings, published in the journal Sleep, also revealed the magnitude of this increase is greater than the effect found in a previous study of 60 mg of codeine.

The results, combined with data from previous research, suggest increased pain sensitivity in tired people is the result of their underlying sleepiness.

Dr. Timothy Roehrs, an expert in sleep disorders and their treatment based at the Henry Ford Hospital in Detroit, said: “Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures.

“We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine.”