Fluctuations in sleep duration can harm mental health, latest research reveals.
Two studies reported in the journal Sleep found that sleeping too less or too more than the usual can increase the risk of depression.
In the first study, researchers looked at 1,788 adult twins. While analysing the participants' sleep duration and its impact on their mental health, they found that constant variations in sleep duration activated genes linked to depression.
Sleeping seven to around nine hours every night was associated with 27 percent heritability of depressive symptoms, compared to the 53 and 49 percent heritability of depressive symptoms associated with sleeping five hours and 10 hours per night, respectively.
"We were surprised that the heritability of depressive symptoms in twins with very short sleep was nearly twice the heritability in twins sleeping normal amounts of time," said principal investigator of the study Dr. Nathaniel Watson, from the University of Washington Medicine Sleep Center US, said in a news release. "Both short and excessively long sleep durations appear to activate genes related to depressive symptoms."
The second study included 4,175 people, aged between 11 and 17. Poor sleep, i.e. sleeping six hours or less than that, was directly linked to depression.
Sound sleep has a crucial role in the mental, physical and emotional health of both adults and children. The importance of getting a goodnight's sleep in remaining fit and fine is well known. Previous studies have shown that short sleep durations increased the risk of obesity, diabetes, heart problems, depression and affected memory and concentration.
Following is the recommended duration of sleep for adults and children, as provided by the National Sleep Foundation:
- From birth to 8 weeks- 12 to 18 hours
- From three to 11 months- 14 to 15 hours
- From 1st Birthday to Age 3- 12 to 14 hours
- Age three to age five- 11 to 13 hours
- Age five to age 10- 10 to 11 hours
- Age 10 to age 17- 8.5 to 9.25 hours
- Adults aged 18 or above- 7 to nine hours