Sleeping badly could age you as much as five years, a study has revealed.
Just three or four years of broken sleep patterns are linked to a loss of memory and concentration, American researchers found.
They say that poor quality sleep is increases the risk of of having impaired mental faculties by up to 50 per cent – equivalent to a five year increase in age.
Study leader Dr Terri Blackwell, of the California Pacific Medical Centre Research Institute, in San Francisco, said: ‘It was the quality of sleep that predicted future cognitive decline in this study, not the quantity.
‘With the rate of cognitive impairment increasing and the high prevalence of sleep problems in the elderly, it is important to determine prospective associations with sleep and cognitive decline.’
The study, published in the journal Sleep, involved 2,820 men with an average age of 76 years.
Each study participant had their sleep patterns monitored over five nights and then each was tested on functions which involved planning, decision making, error correction, trouble shooting and abstract thinking.
The underlying mechanisms linking disturbed sleep to mental decline remain unknown, the authors noted.
They added that additional research is needed to determine if these associations hold after a longer follow-up period.
Dr Safwan Badr, president of the American Academy of Sleep Medicine, said: ‘This study provides an important reminder that healthy sleep involves both the quantity and quality of sleep.
‘As one of the pillars of a healthy lifestyle, sleep is essential for optimal cognitive functioning.’
The news comes just months after a study revealed that going without sleep for just one night causes changes in the brain similar to those that occur after a blow to the head.
Researchers, at Uppsala University, Sweden, found levels of chemicals that act as biomarkers for brain damage rise after sleep deprivation.
They believe this is because the brain usually clears itself of toxic substances during sleep and the biomarkers increase in response to a sudden build-up of these substances after a sleepless night.
The Swedish researchers said their study supports other previous research which linked a lack of sleep to increased risk of Alzheimer’s, Parkinson’s and multiple sclerosis.
Professor Christian Benedict, from Uppsala University, said: ‘In conclusion, the findings of our trial indicate a good night’s sleep may be critical for maintaining brain health.’