The Big Health Mistake You’re Making With Your Smartwatch

Smartwatches are nearly ubiquitous in triathlon circles these days, with many athletes completely reliant on them for tracking workouts and planning their training and racing schedules. But according to researchers at The Ohio State University, most of us are making a big mistake when using them: We’re not sharing that data with our health care providers.

This tool, which many people wear 24/7, can provide unparalleled insights into many aspects of health and wellness that go far beyond how far or fast you’re running, swimming, or biking.

Sure, it’s fun to look at your run splits or what your heart rate was during that sprint swim set, but what if you could really go under the hood of your own health with the many other data points your watch quietly collects and records even when you’re not working out?

That’s exactly what those researchers at OSU are hoping more people will do, and if you’re among them, here’s what to look for and how to leverage that information for not only improved athletic performance, but – even more importantly – improved overall health.

What to watch on your smartwatch

While the sophistication and quality of data these devices can collect vary greatly across the spectrum of smartwatch options on the market, they all can offer some insights into your health and wellbeing, says Milica McDowell, a doctor of physical therapy, certified exercise physiologist and vice president of operations at Gait Happens, a group of clinicians focused on providing foot health education and resources to support efficient movement.

“Some of the higher-end devices are going to tell us about HRV (heart rate varibility) and resting heart rate, body temperature, and respiratory rates. These are things that really help us characterize how recovered we are,” which is critical information to have, McDowell says.

The following six buckets of smartwatch data may be most useful to your doctor.

Heart rate

Continuous monitoring can identify abnormal heart rate patterns and provide insight about overall cardiovascular health.

“Heart rate can be one of the biggest signals for true disease,” says Dr. Will Haas, a board-certified integrative and family medicine doctor and founder and CEO of VYVE Wellness, a wellness clinic that specializes in integrative medicine and wellness, with a big focus on natural treatments, prevention, and longevity.

“Especially in athletes, it’s not uncommon to see arrhythmias develop,” such as atrial fibrillation, which most basic smart devices will pick up. This can be seen in sudden spikes in heart rate, generally 120 beats per minute or more, he says.

Some of the more advanced smartwatches on the market can provide more detailed electrical rhythm and ECG information and may be able to detect an actual arrhythmia.

“Any time you’re seeing a full-blown arrhythmia or these sudden spikes in heart rate along with shortness of breath, dizziness or chest pain, those are big red flag symptoms,” Haas says.

And you should absolutely share that data with your health care provider as soon as possible.

Heart rate variability

Beyond simple heart rate data, heart rate variability is another important data set many smartwatches provide. HRV can seem a little confusing at first, says Dr. William B. Workman, a double-board certified orthopedic surgeon and orthopedic sports medicine specialist with Walnut Creek Orthopedics & Sports Medicine and adjunct clinical associate professor at Stanford University School of Medicine in California.

“The metric is counterintuitive, as the higher the number, the better,” he says. But it’s a measure of how fit, recovered, and relaxed an individual is.

It helps you understand this by measuring “how consentient that little time window between hearts beats is,” McDowell explains. For example, the fitter you are, the lower your resting heart rate will be. That means fewer beats per minute and a longer interval (higher number) between each beat.

On the flip side, those who are less trained, unwell, or older typically have a higher resting heart rate and shorter interval (lower number) between heart beats. “So you’re always looking for a higher HRV number,” she says.

Normal HRV levels vary by age and fitness level, but younger adults are usually between 55 and 105 milliseconds while older adults may be in the 20 to 45 millisecond range – HRV usually decreases over time as part of the normal aging process. Young, highly trained athletes can sometimes exceed 200 milliseconds.

Respiratory rate

How often you breathe is another piece of data some watches track.

Triathletes, and indeed any dedicated endurance athlete who’s training mindfully, should see an improvement in fitness over time. And respiratory rate is a strong indicator of your resting fitness, McDowell says.

“A typical respiratory rate for an adult is between 12 and 20 breaths per minute, which is actually a very wide range,” she says.

However, some experts say you should aim to bring your respiration rate under 10 or even eight breaths per minute. This is something you should work with your doctor to pinpoint for your unique situation, McDowell says.

One reason why respiration rate can be so beneficial to track is because it’s an important marker of overtraining. Endurance athletes, especially triathletes who are working to train three sports at one time, are particularly vulnerable to overtraining.

“If your respiratory rate is increasing, you’re doing too much. You’re on the verge of getting sick, you’re overtraining, or you’ve got something else going on that needs to be looked at,” McDowell says.

Blood oxygen levels

Alongside your respiration rate, your blood oxygen saturation level can also provide a window into respiratory and cardiovascular health. This is a measure of the percentage of hemoglobin in oxygen-carrying red-blood cells.

Every cell in your body needs oxygen to function properly, so a higher saturation level means your body is circulating adequate levels of oxygen-rich blood to support physical activity, energy production, organ function, and overall health.

Normal blood oxygen levels are usually between 96% and 100% and show that your cardiovascular and respiratory systems are working properly. However, hypoxemia, or low oxygen levels, can indicate that something is wrong, such as swimming-induced pulmonary edema.

If your blood oxygen saturation levels drop below 92% at night, “that could be a tip-off for sleep apnea,” Haas says, so it’s important to talk to your doctor if you notice nighttime dips in O2 levels.

At any time of the day or night, if you’re seeing a decline in O2 saturation levels while also experiencing shortness of breath, chest pain, rapid heart rate, dizziness, or confusion, seek immediate medical attention.

Age, altitude, underlying health conditions, and the use of certain medications can all affect your blood oxygen levels. If you notice that over time, your average O2 level seems to be declining, bring that to your doctor’s attention as it could mean a chronic lung or heart condition has developed.

Changes in body temperature

Not all devices can manage it, but if yours can, tracking body temperature can also sometimes let you know a little earlier when you’re about to get sick. For example, if you’ve noticed that your core body temperature elevates when it otherwise shouldn’t, such as overnight, that could be an indication that you’re cooking up an infection, Haas says.

Conventional wisdom states that normal body temperature for a healthy adult is 98.6 degrees Fahrenheit (37 degrees Celsius). In reality, there is often some variation in an individual’s body temperature, which can be influenced by any number of factors including hormonal shifts, meal timing, the weather, infection status, and more.

But the beauty of a smartwatch that tracks and records body temperature on a regular schedule is that you’ll be able to spot patterns over time. A single, slightly elevated reading taken as a snapshot in the doctor’s office may not mean much, but if your body temp is consistently running a little high, that’s definitely worth mentioning at your next doctor’s visit.

Sleep quality

“Sleep is a cornerstone of preparing for your next training,” McDowell says. “It’s critical because it tells us a little bit about the percentage of the day that you’re neurologically and cognitively recovering, and it also tells us about your physiology and your musculoskeletal recovery.”

With sleep, consistency is key. Most healthy adults should aim to get between 7 and 9 hours of sleep per night. But some people are able to feel well on less while others may need a little more. Whatever your normal number is, keep an eye on it, and make note if it starts to shift either direction.

“If you’re somebody who gets four hours one night, six another, and then eight the next, that’s kind of wreaking havoc on your melatonin and cortisol cycling – your awake versus rest time,” McDowell says. “So the science-based goal really is just to be consistent.”

Smartwatch data red flags

In addition to those key data buckets, many watches also provide insight into other factors that may be an early warning sign when something’s wrong. Workman, who is also an accomplished triathlete, recommends watching out for the following red flags.

• Abnormal heart rate. Whether you experience persistent tachycardia (a higher than normal heart rate) or persistent bradycardia (a lower than normal heart rate), either can indicate that something is wrong that needs to be checked out ASAP.
• Severe sleep disturbances. Frequent insomnia will impact your ability to not only recover from workouts, but also to engage with the rest of your life fully. In addition, frequent short sleep interruptions could indicate sleep apnea, a treatable condition that can sometimes be difficult to diagnose.
• Sudden changes in activity levels. Any triathlete who’s ever been injured knows rapid declines in physical activity can suggest health problems.
• Persistently high stress levels. Chronically high stress levels can negatively impact overall health. Some watches have settings to monitor stress levels. If yours does, pay attention to it, and if you’re running consistently high, try to determine why or bring that to your doctor’s attention for further investigation.

How to use your smartwatch health data

To get the most out of your smartwatch and the reams of data it can collect, Haas recommends using it “as a mirror and not necessarily a judge.”

To do this, start by establishing a baseline that shows what’s normal or typical for your body. Surfacing deviations from those baselines are where these watches really shine.

Once you have some collected data, “use them for regular check-ins,” Workman says. “Review and analyze weekly or monthly trends. Use the data to set specific fitness, sleep, or wellness goals and track your progress. And, of course, share the data with your doctor.”

You can show your doctor your data on your phone, but many smartwatches have companion apps that offer insights and recommendations you can use to get the most out of it, Workman says.

“The bottom line for me is that a smartwatch is a way to give objective feedback about health and wellness where otherwise we are relying on subjective input that is influenced by emotion and lack of knowledge,” Workman notes. “It’s a good way to stay honest about how well a person is taking care of fitness and recovery.”

However, be prepared that not all health care providers will know what to do with this information, Haas says. “Conventionally, physicians of this generation, myself included, weren’t necessarily trained on this sort of information and data, and may not necessarily know what to do with it.”

But he notes that functional medicine physicians, regenerative integrative medicine practitioners, and primary care doctors who have an athletic background might all have a better orientation around such data and how best to leverage it for improved health outcomes.

“You can’t interpret this data completely in isolation. You have to draw correlations to other pieces of medical data, and that’s why it’s so important to share this information with your physician, even if they are conventionally trained,” says Haas, who is also a runner, duathlete, and triathlete.

Doing so opens the conversation and allows them to make connections and suggestions for tests or other tools they might not have thought of, such as measuring hormone levels or checking in with your gut health.

What’s more, you can become an ambassador for the endurance community and help educate your doctor on the nuances of this data, McDowell says.

“Most general practitioners are not endurance athletes,” says McDowell, a 13-time full-distance triathlon finisher. They may find it hard to believe the multiple workouts per day triathletes tend to log, and they might dismiss you as either nuts or healthy as a horse and not look more closely at the data you’re presenting.

But McDowell recommends advocating for yourself, especially if you see something in the data that’s new or concerning. “I absolutely think it’s in our best interest to provide that information to the medical team because it helps them see longitudinal information about you over time,” rather than just one snapshot collected that day in the office.

The more information you can provide, the better they can know what’s normal for you and when it’s time to intervene. “As a medical provider, I would love it if more people were to walk into my office and say, ‘Here’s my last six months of data,’” she adds.

And that’s one of the things “that’s on us to do,” she says, speaking as a triathlete, “to help our providers better understand us and where we’re coming from.”

Putting that data in the hands of someone who can make better evidence-based decisions about how to manage your health can make a big difference in your health outside the sport as well as your athletic performance, McDowell explains. “Why would you be hiding recent months of data from a person who’s trying to help you?”

Lastly, no matter which type of watch you have, stay consistent with using it. McDowell notes that some people look down on certain devices. For example, some people poo-poo Apple Watches because their sleep data tends to be a little less robust and accurate than other devices.

“But if you’re using the same Apple Watch day after day, that error is the same, so it doesn’t really matter if it’s inaccurate,” she says. The watch will still show you if there’s been a change in your normal, baseline readings.

However, if you use a mix of different devices “then you’re really mixing Apples with pomegranates,” she says.