New UK research has found that as many as one in five young people regularly wake up in the night to use social media.

Carried out by Professor Sally Power, Co-Director (Cardiff) Wales Institute for Social & Economic Research, Data & Methods (WISERD), the research looked at more than 900 school pupils aged between 12-15 years, who were asked to complete a questionnaire on their sleep and nighttime social media habits.

The students were asked about their bedtimes and waking times as well as how often they woke up at night to check social media.

Participants were also asked about how happy they were with various areas of their life including school, friendships and appearance.

Published in the Journal of Youth Studies, the responses showed that one in five pupils reported "almost always" waking up to log onto social media, with girls much more likely to use social media during the night than boys.

In addition pupils who woke up nearly every night to use social media, or who didn't wake up at a regular time in the morning, were around three times more likely to report being constantly tired at school compared to those who never log on at night or had a regular wakeup time each day.

The study also found a link between always being tired at school and being on average significantly less happy than other young people, suggesting that logging onto social media during the night could be affecting young people's happiness and wellbeing.

Calling the number of young people affected by the lack of sleep "small but significant," Professor Power believes that the "use of social media appears to be invading the 'sanctuary' of the bedroom."

Although the findings support growing concerns and previous research on young people's nighttime use of social media, the exact cause of the tiredness at school could be one of many possible explanations.

However the results come after a 2015 study also found that U.S. teens are increasingly sleep-deprived. After finding that in 1991 72 per cent of 15-year-olds reported sleeping a minimum of seven hours a night on a regular basis, compared to just 63 per cent reporting the same in 2012, lead author Dr. Katherine W. Keyes also suggested that the increasing use of social media could be one of the main reasons for the sleep problem among teens.

A study published last year also observed that among university students a lack of sleep is linked to a higher level of social media use, also finding a direct connection between a chronic lack of sleep, a bad mood, lower productivity, and more time spent checking Facebook.