Do wearables make us healthier? It depends.
Tracking your health with wearable technology such as watches, fitness trackers and rings has become ubiquitous. According to Deloitte, 57% of households have a smartwatch or fitness tracker, and 87% of wearable owners track health metrics with their devices. This ‘quantified-self’ movement is changing how people think and talk about health, and the fitness and health tech industry is quick to allege them to be the best way to take control of your well-being. Even the healthcare industry is putting its hat in the ring and claiming they can save lives or at least make us live healthier lives. A lot is riding on these devices but are they really making us healthier? Well, it’s complicated.
The wearables have advanced a lot since they first came out. Besides the basic body functions such as heart rate (HR), distance, and speed, we can now track calories, sleep, heart rate variability (HRV), recovery status, blood glucose, and much more. The problem is that most people still don’t know what to do with all the data. Any behavioral scientist can tell you that knowledge alone isn’t enough to change behavior. Some people still choose to smoke even with its commonly known risks to health.
Mixed messages
A couple of days after going on vacation where all I did for exercise was walk about an hour a day, I got an Apple Health notification that said I had been burning fewer calories in the past week than normal. A day later another health app that has access to the same data told me that I had been more active than usual lately. What is one supposed to do with such mixed messages? I took it as just another annoying example of a bad algorithm, but what about someone who reads their wearables’ suggestions like a gospel from God?
Whereas some studies are promising, the track record of wearables’ ability to make us healthier and give us accurate data seems dubious. One of the reasons is that people are, well, complicated. Many studies show that the initial enthusiasm and motivation with wearables wane out quite quickly, and about a third of the users will stop using them altogether or disregard the data they’re seeing. A study that tracked weight loss over two years showed that the group who used wearables lost less weight than the group who didn’t use wearables to track their exercise and calories. The study authors speculated that being able to see how many calories they burned during exercise made people eat more.
In general, when it comes to calorie counting, the wearables are way off. A Stanford University School of Medicine tested seven different activity trackers and found that none of them measured energy expenditure accurately. Even the most accurate device was off by an average of a whopping 27%! Energetics and metabolism are more complicated subjects than a simple plus-minus game. Our bodies don’t work like machines because they’re not products of engineering but products of evolution. If you count on your device to tell you exactly how many calories you can eat to lose (or gain) weight, you could be setting yourself up for a big disappointment.
How was your sleep?
The importance of sleep to our health and longevity has finally reached a consensus in the overall population. Unfortunately, many sleep medicine experts, as well as studies in sleep wearables reveal that health trackers do a poor job at measuring your actual sleep (duration, sleep cycles, and wakefulness) although they can do a good job at recording certain parameters like body temperature, HR and heart rate variability (HRV).
I have owned an Oura ring for almost 5 years and it has both helped me and baffled me in about an equal amount. I find it useful in assessing my resting HR, body temperature, and HRV but somewhat useless when it comes to actual sleep data and recovery. By tracking my body temperature I could predict when my periods would start, and my resting HR can tell me when I’m not recovered from a workout or long travel across time zones. But the ring frustrates me to no end by regularly telling me that I’ve been in deep sleep when in fact I’m reading or watching TV. Similarly, I often get a good sleep score although I’ve had a night of tossing and turning because of too much on my mind.
I also feel that Oura doesn’t appreciate athletes or anyone whose exercise routine is more strenuous than a brisk walk around the neighborhood. Any time I go for a bike ride longer than two hours the ring “freaks out” and gives me a low activity score. These longer workouts also result in a low recovery status the next day even if I get 9 hours of sleep and feel refreshed in the morning. I would never be able to be a hardcore competitive athlete if I followed the ring’s advice.
But, even with the limits of accuracy, most sleep experts agree that sleep trackers can help people realize how their lifestyle choices such as alcohol use, or having a late dinner affect their sleep quality and thus hamper their readiness for the following day. For some people having hard data about how these interactions work can be strong enough an incentive to change their sleep hygiene which helps them improve their sleep, and ultimately health.
Trust your feelings
Competitive athletes are one of the biggest market for wearables, and companies pledge them to be an affordable and easy way to monitor training quantitatively and prevent injuries. A pilot study among athletic trainers and strength and conditioning coaches revealed, however, that 76% of the interviewees had a “very negative” verdict on wearables and their ability to meet the needs of the end user.
“If you track it, the results will come” goes the saying but when it comes to wearables, well, it’s a bit more complicated than that. I do agree that tracking your workouts and e.g. heart rate is sometimes super important. A person recovering from a long illness should wear a heart rate monitor to make sure they’re not overdoing it. When people ask me if they should get a wearable my question is “What are you going to use it for”? If you’re just starting to exercise and you have no previous background in regular exercise meaning you’re not good at assessing when you’re going easy or hard, wearing an activity tracker can give you general guidance. Similarly, if you’re training for a sporting event it’s useful to measure HR, HRV, mileage, power, etc. so you can track your progress and keep an eye on overtraining. Just remember to always wear a chest strap, otherwise, the HR might not be accurate.
I feel like the longer I’ve been an athlete, the less I depend on technology. I know my body well and I can tell pretty accurately when I’m on my anaerobic threshold or just cruising in zone 2. If I’m in the gym and my heart is pounding after pushing a weighted sled at full speed across the room but my wristwatch says my HR is 90, I know it’s full of shit. At the end of the day, you always have to rely on your feelings, not technology. The good-old ‘rate of perceived exertion’ (RPE) never fails.
Just move
Wearables are not a magic bullet to better health and performance. They can be great tools but you still have to be willing to do the hard work whether it’s being active, losing weight, or sleeping better. Also, knowing what data to track and what to do with it is key to getting the best out of your wearable.
Having hard numbers about your health and progress at your fingertips can be a powerful incentive. If you’re a person who loves data or needs regular feedback and reminders to keep on track with your goals, wearables can be very beneficial. On the other hand, if using an activity tracker makes you overthink your health and obsess about your activity level, sleep, or burned calories, and instead of helping you, it increases your overall anxiety, it might be time to toss your gadget into a drawer. The most important thing is not to be the king or queen of Strava but to get out there and move in whatever way is the most enjoyable and doable for you.
