In what could give sleepless nights to parents, a new study has found that the adolescents in higher classes are chronically sleep deprived and suffer from disturbed sleep patterns.

Listing television and internet as main factors causing chronic sleep deprivation amongst youngsters, the study found that higher the class the student was studying in, the lesser sleep he or she got.

The findings of the study conducted by researchers at the University college of medical sciences and GTB Hospital in New Delhi, show that sleep debt of approximately one hour per day was seen in all adolescents and progressed with higher grades.

The research team studied sleeping habits of students from classes IX-XII in an average sample age of 15.1 years and found that the total sleep time was 7.8 hours per day.

Most of the students said that they went to bed by 11 pm and took 23.6 minutes to leave the bed after waking up. Though sleep efficiency of the sample was 92.6 per cent, refreshing sleep was reported by less than half of them.

According to the experts, the adolescents need at least 8-9 hours of night time sleep for optimal daytime alertness.

Discrepancy between the ideal sleep debt increased with higher grades and this resulted in surging prevalence of daytime sleepiness in corresponding groups.

The presence of media, television and internet, in the child's bedroom delays the bedtime and wake-up time.

The school children spend less time in bed and are more tired during the day as compared to their peers with no such access in their bedrooms, the study said.

The data available in the study thus suggests that most of the adolescents, especially the higher graders, are chronically sleep deprived.

The study found that while ninth graders had eight hours of sleep, the tenth graders 7.7 hours, eleventh graders 7.9 hours and class XII students managed with only 7.6 hours of sleep on an average count. Most of the respondents complained of pain in the legs.

Daytime napping and sleepiness were prevalent in the study and its incidence increased with higher grades. A whopping 69.8 per cent of twelfth graders confessed to taking naps during daytime and 54.2 per cent of daytime sleepiness.

While daytime sleepiness of the tenth and the eleventh graders was at 39.1 per cent and 39.7 per cent respectively, only 37.2 per cent ninth graders complained of sleepiness. Interestingly, nocturnal awaking increased progressively until eleventh grade but dropped down in twelfth standard. But despite lower incidence, the frequency of nocturnal awakenings in higher grades was quite high, the study revealed. - Bureau Report