A British team led by researchers from the University of Manchester has discovered that people who regularly sleep for more than 11 hours or less than 4 hours are 2-3 times more likely to have the incurable disease, pulmonary fibrosis, compared to those who sleep for 7 hours a day.
According to the study reported in the recent issue of the Pnas journal, the researchers attribute this association to the body clock.
Our internal body clocks regulate nearly every cell in the human body, driving 24-hour cycles in many processes such as sleeping, hormone secretion and metabolism.
In the lungs, the clock is mainly located in the main air carrying passages. However, the team discovered that in people with lung fibrosis, these clock oscillations extend out to the small air spaces, called alveoli.
Studies on mice revealed that by altering the clock mechanism it was possible to disrupt the fibrotic process making the animals more likely to develop pulmonary fibrosis.
The researchers then showed, that pulmonary fibrosis is associated with short and long sleep duration using human data from the UK Biobank.
People who reported that they regularly sleep 4 hours or less in per day doubled their chance of having pulmonary fibrosis while those sleeping for 11 hours or more in a day tripled their chance of having the disease, compared to those sleeping 7 hours per day. At a lower level, but still elevated, risks were also seen in people who like to stay up late at night.
In a report released Monday on the university's website, Dr. John Blaikley from The University of Manchester, who led the project said: "Pulmonary fibrosis is a devastating condition which is incurable at present.
Therefore, the discovery that the body clock is potentially a key player potentially opens new ways to treat or prevent the condition. If these results are confirmed, then sleeping for the optimal time may reduce the impact of this devastating disease."
For his part, Dr. Peter Cunningham, joint lead author on the paper, said: "Previous studies have shown that the clock also plays an important role in infection, cancer and diabetes. The discovery that the clock plays a role in fibrosis suggests that altering these oscillations could become an important therapeutic approach."