Apple鈥檚 recently released Series 6 smart watch incorporates a new feature: it can measure your blood oxygen levels. The tech must have been years in the making, but the timing of its release worked well given we are in the middle of a global respiratory pandemic.
The amount of oxygen in the blood is important medical information, and in hospitals it is usually measured with a device called a pulse oximeter, which shines a light through the finger or earlobe. Blood carrying more oxygen absorbs light differently.
It is already possible to buy a fingertip pulse oximeter for use at home for about 拢20. Now Apple says it has replicated this function in its high-tech watch, which shines a light onto the back of the wrist and measures the light reflected back with embedded sensors. For a readout, the user must keep their arm still for 15 seconds, and the device will also take periodic background readings when the person happens to be still, day and night.
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In a press statement, Apple was vague about the purpose, saying it offers 鈥渋nsight into overall wellness鈥�, and didn鈥檛 answer 快猫短视频鈥檚 requests for further details before publication. A spokesperson couldn鈥檛 share any published research showing how oxygen monitoring would help a typical healthy person.
But tools to track personal health may come to the fore as the coronavirus pandemic continues. Home oxygen monitoring is in no way a test for infection with covid-19 鈥� but it could help people who have already been diagnosed and aren鈥檛 sick enough to be in hospital but want reassurance about their condition. Some UK clinics are already piloting 鈥渧irtual wards鈥�, where people who might otherwise have been admitted to hospital stay at home with frequent telephone check-ups, and pulse oximetry is an important part of their monitoring.
There are other conditions for which home oxygen monitoring can be useful, for instance chronic obstructive pulmonary disease 鈥� a long-term lung condition that can cause people to need supplementary oxygen.
It could also help when people use the electrocardiogram (ECG) function that was introduced with the Series 4 watch, launched in 2018. This can detect if people have disturbed electrical activity of their heart. The criticism of that feature was that it might detect harmless small changes that have no effect on the body 鈥� but if someone discovers they are having low oxygen levels at the same time as the heart rhythm problems, that information becomes more useful.
Another potential use is with alerting people that they have sleep apnoea, when they have problems breathing at night, usually caused by being overweight. This can cause people to wake up when their blood oxygen gets too low, although they may not be aware of how much their sleep is being disturbed. The night-time monitoring function could be useful in this case.
鈥淐ould鈥� is the operative word, though. Most existing pulse oximeters are applied to the finger or earlobe so it is unclear how well this new method will compare. And even highly accurate devices sometimes give erroneously low readings when people鈥檚 hands are cold, says Andy Whittamore, clinical lead for Asthma UK and the British Lung Foundation. 鈥淭here are a few gaps there in terms of how we interpret this device,鈥� says Whittamore.
Even Apple says in the that the oxygen measurements are 鈥渘ot intended for medical use, including self-diagnosis or consultation with a doctor, and are only designed for general fitness and wellness purposes鈥�. Until the firm releases data about how accurate the watch鈥檚 readings are and how people tend to use them, it is hard to know how useful the function will be. 鈥淚f we knew the device was absolutely robust and accurate, then there would be a place for it,鈥� says Whittamore.
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