From digital insoles that correct your walk to bracelets that chart your fertility, wearable health technology is a booming industry.
But are these gadgets — which can be eye-wateringly expensive — an accurate way to check our health?
‘Fitness trackers can play a role in getting us motivated to exercise and become more aware of our well-being,’ says Professor Ian Swaine, a sport and exercise scientist at the University of Greenwich.
‘However, the novelty often wears off and while there have been significant advances in the past couple of decades, the technology involves sensors that aren’t always reliable, combined with computer estimations and algorithms that crunch the numbers into results — and research has shown this can be fraught with inaccuracies.’
Dr Nisa Aslam, a London-based GP, adds that although some of this technology can help monitor conditions such as diabetes, ‘initial health assessments and annual check-ups still need to be performed in person by a medical professional’.
We asked Professor Swaine and Dr. Aslam for their opinions on some of the latest gadgets; we then rated them.
From digital insoles that correct your walk to bracelets that chart your fertility, wearable health technology is a booming industry
Activity and heart ‘watch’
Fitbit Charge 5, £129.99, fitbit.com
Claim: The ‘most advanced’ Fitbit, this monitors activity, heart rate and sleep patterns, checks for ‘irregular heart rhythms’ with an ECG and measures stress with an electrodermal activity (EDA) sensor, says the maker. A daily ‘readiness score’ advises exercise or rest.
Expert verdict: ‘This reflects the trend towards health management at home, fueled in part by difficulties seeing GPs face to face,’ says Professor Swaine. ‘But a wrist monitor should never replace a doctor when it comes to heart health, as wrist sensors can’t measure irregular heart rhythms very accurately.
It claims it identifies stress levels through an EDA sensor — by measuring skin sweating — but we sweat for many reasons.
‘The ‘readiness score’ could help increase your awareness of the need to rest sometimes but, overall, there’s not much science to back up the new functions.’
Patch to follow blood sugar levels
FreeStyle Libre 2, £96.58
FreeStyle Libre 2, £96.58, freestylelibre.co.uk
Claim: This stick-on sensor connects to an app and can be used to ‘check your glucose anytime, anywhere, with just a scan of your smartphone’. An alarm on your phone sounds if levels are too high or too low.
Expert verdict: ‘This clinically accurate device is a game-changer for people with type 1 and type 2 diabetes and is available to some on the NHS,’ says Dr Aslam.
‘The small, discreet sensor, worn for 14 days, monitors glucose levels in the interstitial fluid — the clear fluid that sits just under the skin — liberating patients from the hassle and pain of finger-prick blood glucose monitoring.
‘Readings show if glucose is trending up or down. An alarm alerts patients if their glucose is too low or too high. It saves a lot of hassle and offers peace of mind.’
Bracelet that monitors fertility
Ava Fertility Tracker, £249, avawomen.com
Ava Fertility Tracker, £249
Claim: This bracelet helps women track their monthly cycle by monitoring nine ‘biomarkers’, including skin temperature, breathing, heart rate and blood flow. Worn overnight, it tells you every morning if it’s a good day to try for a baby. The maker says it can detect an average of ‘five fertile days per cycle with 89 percent accuracy’.
Expert verdict: ‘Studies show temperature and heart rate change during a woman’s monthly cycle, increasing around the days of ovulation, when an egg is released from the fallopian tubes and a woman is at her most fertile,’ says Dr Aslam.
‘Tracking these factors can indicate with a pretty high degree of accuracy when ovulation occurs.
‘There is some robust research behind it, but this bracelet is very expensive. I suggest patients keep a diary using cheap, chemist-bought ovulation tests. This is adequate for most.’
Sleep tracker you pop in your pocket
WHOOP 4.0, £264, whoop.com
Claim: Worn on the wrist or put inside pockets in sports bras and pajamas to monitor ‘heart rate, respiratory rate, blood oxygen level and skin temperature, it also tracks sleep and breathing patterns’, says the maker.
Expert verdict: ‘Monitoring heart rate and physical movement while sleeping provides a little information, but to measure overall sleep quality requires a polysomnogram — a brain scan where electrodes measure brain waves, muscle movements, breathing and heart rate,’ says Professor Swaine.
‘Using this type of tracker can cause people to become obsessed with how many hours of sleep they’re getting. A better test is how you feel doing your everyday activities.’
Worn on the wrist or put inside pockets in sports bras and pajamas to monitor ‘heart rate, respiratory rate, blood oxygen level and skin temperature, it also tracks sleep and breathing patterns’, says the maker. A file photo is used above
Earbuds for heart rate
Amazfit PowerBuds Pro, £59, amazon.co.uk
Amazfit PowerBuds Pro, £59
Claim: These wireless earbuds ‘measure your heart rate as you exercise’ and give ‘posture reminders’ if you sit for too long.
Expert verdict: ‘Measuring heart rate during exercise can, in theory, help you regulate your effort as you go — and estimate how hard you’ve worked,’ says Professor Swaine.
‘This works well during aerobic exercise such as running or cycling, but it’s not so useful for resistance exercise such as weights or Pilates, where you can be working your muscles hard.
Ear monitors measure heart rate through changes in reflected light as it passes through the skin inside the ear — but chest monitors are more accurate because they’re closer to the heart.
The ‘posture reminder’ is based on the idea that you’re less active when you sit more.
‘However, research shows you gain health benefits from distinct periods of exercise, so the jury’s out on how useful this is.’
Wristband to solve snoring
Viatom Sleep Pulse Oximeter, £134.99, stressnomore.co.uk
Claim: A wrist monitor that measures blood oxygen levels to help ‘Covid patients spot deterioration’. It also acts as a ‘sleep apnea monitor’, says the maker.
Expert verdict: ‘Sleep apnea is a condition in which breathing temporarily stops while you sleep, causing snoring and a drop in oxygen levels,’ says Dr Aslam.
This wristband and finger sensor monitor oxygen levels while you sleep and vibrate if they drop to a preset low level. It could be useful for those with sleep apnea, Covid-19, pneumonia and COPD [chronic obstructive pulmonary disease, a term for conditions which cause breathing problems]alerting the wearer to seek early medical attention.
‘A far cheaper alternative is a pulse oximeter you clip on your finger, which costs around £10 and is very accurate.’
Watch to check hydration
Mifo Walkabout Watch 2, £69.99, mifo.co.uk
Claim: ‘A waterproof smartwatch that measures heart rate, blood oxygen, hydration, sleep patterns and stress levels,’ says the maker.
Expert verdict: ‘Hydration is predicted based on how much exercise you’ve done and how much water you’re likely to have lost [about one litre per hour during exercise] — it can’t actually measure the water levels in our cells,’ says Professor Swaine.
‘Most people know to avoid exercising without water. You should use feelings of thirst to dictate how much water you drink.
It also claims to measure stress through heart rate variability. However, these fluctuations are notoriously difficult to measure and interpret accurately.
‘It is a reasonably priced general fitness tracker, though.’
Insoles to improve your gait
Digitsole, £89.99, decathlon.co.uk
Claim: Digital insoles that promise to measure ‘ten aspects of your walking or running technique’, says the maker, ‘to improve your stride technique and efficiency’.
Expert verdict: ‘These contain embedded sensors which measure changes in pressure as you walk or run,’ says Tim Veysey-Smith, a sports podiatrist at Active Podiatry in Goudhurst, Kent.
This helps to measure stride length, foot strike pattern and velocity of pronation and supination [rolling in and out of the foot, respectively].
But knowing what to do with the data can be difficult. You need to work with a qualified expert so it can be properly interpreted.’