Teenagers who go to bed late and have long lie-ins are almost three times more likely to develop asthma, according to a new study.
Researchers from the University of Alberta in Canada discovered that youngsters who have a disrupted body clock, due to sleeping late at night and in the morning, will harm their lungs.
Symptoms of the inflammatory respiratory condition include wheezing and shortness of breath and some sufferers may need a reliever inhaler to help alleviate severe symptoms.
The study found that teenagers who went to bed late and subsequently slept late into the morning could be at risk of the immune function of the lungs being negatively affected, leading to an onset of asthma.
And those youngsters who spend hours at night scrolling through social media on their smartphones fared worse, as the blue light further disrupted the body's ability to distinguish night from day.
Researchers studied almost 1700 teenagers, aged 13 to 14, and nearly one in 10 self-confessed 'night owls' were three times more likely to suffer from allergies and asthma-like symptoms, such as sneezing and a runny nose.
Dr Subhabrata Moitra, senior author of the study, urged parents to enforce a stricter bedtime for the youngsters.
"Teenagers are not naturally night owls, whatever they might think. But our results suggest there's a link between the time they prefer to go to sleep, and asthma and allergies," he explained.
"So the advice to parents, based on these findings, might be for them to make sure their young teenagers go to bed between 9:30 and 10:30pm, and put down their electronic devices two hours before that."