Your smartwatch knows when you are sleeping, knows when you're awake and if you have a recent model, it could soon detect signs of a common sleep disorder.
Australia's Therapeutic Goods Administration has for the first time approved smartwatch software from Apple and Samsung to detect and analyse bedtime breathing disturbances.
The analysis could indicate whether their users show symptoms of moderate to severe sleep apnoea, which medical professionals tentatively welcome.
Obstructive sleep apnoea is a potentially serious disorder in which a person stops breathing for short periods repeatedly during the night, resulting in disrupted rest.
About five per cent of Australians are estimated to suffer from the disorder, according to Neuroscience Research Australia.
But the condition is widely under-diagnosed, specialist sleep physician David Cunnington said, and bringing it more attention could prompt sufferers to seek medical help.
"There are many more people in the community than have been diagnosed, which is why anything that will increase people's awareness of it and will give them a notification that it may be going on is going to be helpful," he told AAP.
Sleep apnoea is typically diagnosed during a one-night sleep study, Dr Cunnington said, but more advanced wearable devices could potentially collect data over longer periods and help medical professionals assess the severity of a condition.
"For me, as a sleep physician, I'm absolutely interested in whatever data people are collecting from their wearables and smartwatches," he said.
"If I'm trying to look at how people respond to treatment or what other factors might be impacting things, that's where longer-term data from a wearable can be really helpful."
The software on Apple Watches is not approved to diagnose the disorder but to "identify patterns of breathing disturbances suggestive of moderate-to-severe sleep apnoea" in adults.
Notifications from the app, which will analyse a user's breathing over 30 days, are designed to prompt a conversation with a medical professional.
Apple will issue sleep apnoea software updates for three Watch models from Wednesday, while Samsung has already begun updating its Health Monitor app with sleep-monitoring software for compatible devices.
Samsung's software will monitor a user's sleep for four consecutive hours over two nights, after which the feature will turn off automatically.
The software was not designed as "a medical device", Samsung Electronics Australia wearables head Kylie Mason told AAP, but to alert wearers to potential health issues.
"That's the cool thing about smartwatches: they're getting all this data and allowing you to talk to GPs," she said.
"They're not there to diagnose things or provide technical medical analysis - that's not our job - our job is to show you trends in things happening with your health."
The company's sleep apnoea software is available in Galaxy Watch 7 devices and later models in Australia, and will feature in the upcoming Galaxy Watch 8 when it launches in August.
