London: People who love sleeping or who are sleep deprived please note, it can age your brain up to seven years.

According to a study, researchers in Britain have found that getting less or more than six to eight hours of sleep every night can trigger a person's mental and physical decline, and ultimately lead to an early death.

Seven hours of shut-eye will keep the brain in peak condition, according to the researchers at the University of London Medical School, who also claim that lack of sleep affects reasoning and vocabulary.

In their study, the researchers found "the magnitude of the effect is equivalent to four to seven years of ageing", a daily newspaper reported.

Following a study of sleep patterns, they said changes over a five-year period in late middle-age affect the function of the brain. Between seven and eight percent of those who slept longer than recommended amount did worse in cognitive tests with the exception of short-term verbal memory.

But a quarter of women and one in six men who failed to get a good's night sleep suffered a decrease in reasoning, vocabulary and cognitive tests, the findings revealed.

Lead researcher Jane Ferrie said, "The main result to come out of our study was that adverse changes in sleep duration appear to be associated with poorer cognitive function in later middle-age.”

The detrimental effects of too much, too little and poor quality sleep on various aspects of health have begun to receive more attention.

However, the study found that the ideal amount of sleep duration of seven hours per night resulted in the highest score for every cognitive test. Among men, a change in brain function was noticeable after less than six hours or more than eight hours of sleep.

The study tested 5,431 participants for two periods over five years alongside a study of London civil servants aged 35 to 55.

(Agencies)