Smartwatches are much more than fashion accessories these days. With its latest range - the Apple Watch Series 6 (from £379) and the cheaper Apple Watch SE (from £269) - Apple is moving more and more into the realms of healthcare. Most notably, the Series 6 can measure blood oxygen saturation.
It's not the first time Apple has hung a USP on health and lifestyle functionality - the Series 4 introduced us to fall detection and ECG (electrocardiogram) measurement, and heart rate measurement was available from the Series 1.
Others have followed suit, and the wearables market now seems firmly focused on a broader range of tracking, as well as fitness.
Read on to find out about some of the key health-tracking features on offer from Apple and wearables brands, and what you could expect to see in the future.
It's all too easy to lead a sedentary lifestyle, especially if pre-lockdown you used to incorporate exercise into your daily commute.
Even 10-minute daily walks can help you build stamina, lose weight and become healthier, according to the NHS. You need to walk 'briskly', though, at a rate of about three miles an hour.
That's where wearables can help. All smartwatches and fitness trackers will count the number of steps you've taken and how far you've travelled (based on GPS if that functionality is available; based on steps if not). Many also track metrics like pace and speed.
If you enjoy walking, a wearable can help you get the most out of your outings, and, if you don't, it might motivate you by giving you a sense of purpose.
Most wearables allow you to set personal targets, meaning you can easily see whether you're meeting them, and some will connect to a smart home speaker, so you can get information about your fitness without needing to get your smartphone out and open the app.
Watch out for the fact that many wearables aren't that accurate when it comes to tracking your steps as you mooch about the house, often mistaking any swing of your arm for a step. Even so, they can give you a sense of how active you're being. Small efforts to get moving during the day all add up to have health benefits. Our guide on has more.
In many ways, the Apple Watch Series 6 doesn't represent an enormous step forwards from the Series 5 when it comes to features, but the new blood oxygen sensor has certainly grabbed attention.
Blood oxygen monitoring, aka SpO2 monitoring, aka pulse oximetry testing, measures the oxygen saturation of your blood.
The new Apple Watch Series 6 (pictured above) can take on-demand readings of your blood oxygen and background readings during the day and night.It works by shining red and green LEDs and infrared light onto your wrist, and measures the amount of light reflected back.An algorithm then estimates the colour of your blood - blood with more oxygen is bright red; blood with less oxygen is darker.
Pulse oximeters have been in the news a fair bit of late. There's currently a trial going on in England called 'COVID oximetry @ home' involving the remote monitoring of patients with coronavirus symptoms using pulse oximeters.Some doctors are saying everyone should have a pulse oximeter just in case, while others question their value for otherwise healthy people.Either way, it's important to remember that a pulse oximetry reading itself isn't enough for a diagnosis.
To stay safe, make sure you follow the latest NHS guidance.
It's also important to remember that smartwatches with pulse oximetry features are not medical devices. In what manufacturers often describe as a 'recreational' setting, though, they can be interesting.If you're a keen alpinist, for example, a wearable that can take on-demand pulse oximetry readings could flag if you're over-exerting yourself.Or a wearable that can take night-time readings could detect signs of sleep apnoea, which you could then discuss with your GP.
Apple isn't the first brand to incorporate pulse oximetry in some format into wearable tech. We test wearables that can take on-demand pulse oximetry readings to see how accurate they are compared to a medical pulse oximeter.Some have impressed us, giving us readings in the same ballpark as our medical pulse oximeter, while others struggled - particularly on darker skin.We'll be putting the Apple Watch Series 6 through our pulse oximetry tests in due course.
Monitoring your heart rate can help you make sure you're pushing yourself hard enough during your workouts, and, if you keep an eye on your heart-rate patterns long term, educate yourself about your overall cardiovascular health.
Heart rate is taken using sensors that measure electrical signals in your heart and check for AFib (atrial fibrillation, irregular heart-rate rhythms).They can also send you alerts if your heart rate goes above or below the normal range.
As with pulse oximetry, though, this shouldn't be relied upon for diagnosis, and nor can it be used for ongoing management of any condition once it has been diagnosed.
Always seek medical advice if you have reason to be concerned.
If you have hypertension, you can use wearable tech to monitor your blood pressure by:
The HeartGuide is extremely hefty: we can't imagine anyone preferring to have this strapped to their wrist all day than to take readings the traditional way.Packing an accurate blood pressure monitor into a slimmer device will be no small challenge, but we're excited to see where Omron and other brands take this technology in the future.
In the meantime, beware of cheap trackers you might see online from obscure brands claiming blood pressure monitoring. Due to the level of tech that would be necessary, these almost certainly can't give you proper readings.
A growing number of wearables will attempt to measure your stress levels and we're even seeing models that claim to gauge your emotional state.
They measure stats such as your heart rate and your heart rate variability (HRV) - the variation in time between your heartbeats - and assign you a stress score, although the name may vary from brand to brand.
Many wearables also offer guided breathing exercises. When you breathe in a more controlled way, you lower your heart rate and increase your HRV. And some will use this information to give you insights as to your readiness for a workout.
One interesting new product is the Amazon Halo, Amazon's new fitness band.The Halo doesn't have a screen - it's a fabric band containing a sensor that gathers a host of health data about you.
As well as run-of-the-mill things such as activity tracking and sleep-tracking, it can also measure your body composition and body-fat percentage, make a digital 3D model of you and use machine learning to analyse your voice, with the aim of helping you improve your relationships and emotional wellbeing.
Amazon says that its Tone feature 'may reveal that a difficult work call leads to less positivity in communication with a customer's family, an indication of the impact of stress on emotional well-being'.It should also be able to tell you things like what events in your day prompt you to snack and whether walking further helps you feel less stressed.
You can't buy the Amazon Halo in the UK just yet, as it's currently only available in the US. It costs $99 (approximately £72), plus $3.99 a month membership.
We don't know yet when it will be fully released to more countries, but it's an interesting example of the way technology is headed.
How useful you find stress and emotion tracking will depend to some extent on your personality and on the device.You might find it really helpful for combating anxiety in these chaotic times, or you might find it a bit creepy, or even naff. The (£99) is a necklace that will give you a stress sensitivity report but it's a fairly tacky product and expensive for what it is.
Sleep can have a huge impact on your health and state of mind.
Insufficient sleep reduces your immunity and puts you at much greater risk of many long-term health and mental health problems.
The sleep data your wearable gives you can only ever be an educated guess, based on data it collects as to your movement and heart rate, so it's best not to get too hung up on it, particularly if you're already prone to lying awake at night beating yourself up for all the things you haven't managed to achieve during the day.
But a wearable with sleep-tracking capabilities can push you towards better night-time routines by making you conscious of how much sleep you're getting (or not getting), which could be good for you if you currently prioritise everything else on your to-do list above sleep.
A wearable can also show you the extent to which activities like exercising late in the day or drinking alcohol just before bed can interfere with your sleep.
Wearables can introduce you to, and help measure, a range of activities beyond walking and running, including ones you can pick up for free from your living room while watching a YouTube tutorial.sFor example, many can track yoga, pilates and dance, which will help improve your posture, balance and flexibility.
If you've spent the best part of a year huddled over a laptop on an uncomfortable kitchen chair, it's important to do exercises to stay supple.Many wearables can only give you top-level stats for such activities, though, so it's important to check the manufacturer site if you're already very into a specific sport and need sports-specific stats.
But for those looking into get into a new type of exercise just a few times a week, stats like heart rate might well be all you're after.
Companion apps, such as Fitbit Coach, also offer short video workouts covering these activities, which you can follow from your phone or computer.
With such a wide range of technology already available, and further developments on the horizon, wearables have come a long way since the days of cumbersome, limited, glorified pedometers.
Wearables are becoming increasingly hi-tech when it comes to health, gathering a vast array of physiological data and even aiming to flag underlying health conditions.
A recent study of more than 30,500 people found that changes detected by the devices in the participants' sleep, activity and heart rate levels, combined with self-reported data, could help identify COVID-19 cases. No surprise, then, that the wearables technology market is surging.
We expect smartwatches will increasingly be used in healthcare in the next few years. We're likely to see data gathered by smartwatches being used more and more for reminding patients to take medication, as an aid to early diagnosis and for remote patient monitoring to avoid healthcare systems being overwhelmed.
And it's not just about wristworn wearables: the smart clothing market is growing too.
Swimsuits containing UV detectors can communicate with your phone to warn you if you're over-exposing yourself to the sun.T-shirts can monitor sports players' biometric data, such as cardiac activity and temperature.
The use of wearables for life-saving medical diagnosis, although still in its infancy, is clearly an area with huge potential.In the meantime, remember a wearable you buy today is no substitute for seeing a doctor. Wearables can make guesstimates about your health and fitness, based on the data their sensors collect. They can be inaccurate and they can malfunction.
What they can do is help you get proactively engaged with your health, helping you build up a more rounded and detailed picture of how your body works, so that, if you do notice anything irregular, you can take it up with your GP.
There's plenty more that the Apple Watch Series 6 has to offer in terms of health features, including detection for hard falls, and the ability to call an emergency contact for you, alerts when noises in your surroundings are so loud they might damage your hearing and reminders to wash your hands properly (this would have sounded patronising just a year ago, but now sounds incredibly useful).