My Experience with Wearable Technology

Throughout my life, I have been fascinated by the use of technology in sports. I remember the triathlon handlebars used by the American cyclist Greg Lemond in the 1989 Tour de France, which led him to victory in the final time trial stage. Or the special biking position of Graeme Obree in 1993, or his "Superman" position in 1995. I also admired the various innovations in bike frames used by the British cyclist Chris Boardman during those years, as well as the widespread adoption of heart rate monitors in the late '80s and early '90s, and the expansion of power meters towards the end of the '90s and the beginning of the 2000s. All these technological innovations in cycling particularly marked me.

Personally, by 1994, I was already using a Polar watch with a heart rate monitor, being the first or one of the first cyclists in my cycling club in Cali, Colombia, to use it. And by 1998, I had my first smart indoor trainer that could simulate slopes, analyze power and pedaling biomechanics, and virtually simulate almost any course I programmed. It was the CompuTrainer by Racermate Inc., discontinued in 2017 due to the rapid evolution of the smart indoor trainer market and the emergence of new technologies and competitors, such as indoor trainers offering direct-drive systems, wireless connectivity, and integration with immersive training platforms like Zwift, TrainerRoad, and Sufferfest. This began to eclipse traditional wheel-on trainers like the CompuTrainer. These new smart indoor trainers provided a more realistic riding sensation, easier setup, and were often more affordable, attracting a broader segment of the cycling community. However, I will leave the topic of cycling indoor trainers for another post.

Regarding wearable technology specifically, the first smartwatches capable of monitoring health, wellness, and fitness variables hit the market in the 2010s. I had the opportunity to experience this technology around 2014, first with the Polar Loop bracelet and later with the first-generation Apple Watch in 2015 and Garmin Fenix in 2019. It should be clarified that it was only around 2018 that these watches were able to perform measurements through heart rate variability (more specifically, heart pulse variability). This allowed for monitoring a greater number of health, wellness, and fitness variables such as physiological stress, sleep quality, maximum oxygen consumption, among others.

In the academic field, there has been great controversy about whether these wearable devices can accurately and consistently measure such variables 24 hours a day, 7 days a week. To obtain such scientific evidence, the ideal would be to have review articles or meta-analyses. The issue is that being a new technology, it is constantly evolving. To date, not only are there smartwatches, but we also have rings, bracelets, bands, sleeves, and even smart glasses. Additionally, the sensors in each of these devices are also evolving and changing, increasing their measuring power and accuracy. So when a scientific article is published about any of these devices, one or more years have passed since it was evaluated. And it turns out that by then, the device has an improved sensor.

Another factor complicating the analysis of the accuracy and consistency of wearable technology devices is the variation in use among people. Factors such as skin tone, the fit of the device, the brand and model of the device, the sensor, the presence or absence of tattoos at the site of device placement, its calibration, the amount of body movement, and even the blood flow in the area where it is located influence its accuracy. For example, it is reported that tattoos and darker skin tones may have difficulties in measuring variables due to the light technology (photoplethysmography) used. If the device is too tight or too loose, it also contributes to measurement errors.

However, if we leave behind these variables and the device has a latest-generation sensor, is properly adjusted and located, and there are no skin variables that negatively influence, nearly a decade of experience has shown me that these devices can become an indispensable element in measuring variables related to health, wellness, and fitness.

Almost 10 years of data accumulated using and comparatively analyzing devices like the Apple Watch Series (including the Apple Watch Ultra), the Garmin Fenix (6 onwards), Garmin Epix, the Polar V2, the Whoop band, and even the Oura ring have shown me that all this wearable technology (those with the latest generation sensors) can measure data such as heartbeats per minute, oxygen saturation, breaths per minute, sleep quality and quantity, physiological stress, calories burned, floors climbed, steps taken, maximum oxygen consumption, heart rate variability (HRV), body battery, acclimatization to heat and altitude, jet lag, and even body temperature with sufficient accuracy and consistency. I have thousands of data points in various scenarios that allow me to corroborate this information: baseline and rest states, states of fatigue, viral conditions, trips to altitude and sea level, different moments of fitness, and correlation on multiple occasions between two or more devices simultaneously (for example, an Apple Watch Ultra on one wrist and a Garmin Epix on the other).

I still could not say that there is accuracy in blood pressure data in those devices that claim to measure it. For this, we are still a few years away. Nor could I say that devices using photoplethysmography are more accurate than chest heart rate monitors that use electrocardiography for their measurements. But let's remember that the purpose of wearable technology is to continuously monitor physiological variables, 24 hours a day, 7 days a week. That it be easily accessible and reasonably priced for most people and that its battery allows these continuous measurements for hours, days, weeks, and months.

What comes in the near future? Better analysis of all these variables using artificial intelligence to issue more appropriate recommendations regarding health, wellness, and fitness; the possibility of non-invasively monitoring blood glucose (blood sugar) and lactate, which would revolutionize the world of sports and applied sports sciences; and having more options to wear this technology with different brands and models. For example, there are rumors that Apple would enter the competition with the Oura ring with its own ring, as Samsung has already announced. I also hope that the sensors evolve to the point where they can match the gold standard of measurement by electrocardiography. I will be very attentive to when these innovations are commercialized and will surely be reporting my experience with them.

Jaime Roa, M.D., M.S.E.P., M.Ed, ACSM-CEP

Founder-CEO & Scientific Director at SportsMedTraining