Being a heavy snorer may cause cancer tumours to grow and spread – because it starves vital organs of oxygen.
A new report has found people who suffer from sleep apnoea – which can block the airways for 10 seconds or more – have far worse cancer outcomes than those who sleep soundly.
It is thought that this starves vital organs of oxygen, which makes the body release a signal protein to form more blood vessels.
In turn, this feed tumours allowing them to grow and spread.
This may explain why those who exercise and get oxygen pumping through their blood may be more protected from cancers than those who lead sedentary lives.
Sleep apnoea is thought to affect an estimated 44 per cent of British middle-aged men and two per cent of middle-aged women having it.
Previous studies has linked sleep apnoea with an increased risk of high blood pressure and stroke but there was no explanation of the linked to more aggressive cancers.
But this new study, which used mice with kidney tumours, suggested it could be down to the process known as hypoxia, where a tissue or organ does not get enough oxygen.
Dr Antoni Vilaseca, of the Hospital Clinic of Barcelona, said: ‘Patients suffering from obstructive sleep apnoea usually suffer from intermittent hypoxia at night.
‘This work shows that intermittent hypoxia has the potential to promote the formation of blood vessels within tumours, meaning that the tumours have access to more nutrients.
‘This is of course an early animal study, so we need to be cautious in applying this to humans