You’re hard pressed to find someone NOT sporting some type of fitness tracker, smart watch, or other wearable health technology product as you walk down the street. In fact, at least 1 in 5 US adults uses a mobile health app or wearable device. Rings, watches, bands, and other wearables have exploded in popularity in the last decade due to the focus on increasing activity, tracking calories burned, and monitoring sleep as a means of weight loss and disease prevention.
But have you ever considered that these fancy devices hold a goldmine of health data, collected over time, and customized to your specific body? In light of the current health challenges we’re facing, there is enhanced attention on understanding our body’s from the inside out, and identifying potential risk factors that are compromising our immune systems.
Scripp’s Research Lab published a study in January 2020 that showed changes in certain physiological metrics, such as resting heart rate, sleep & activity, could predict early onset of seasonal respiratory infections, such as influenza, through the use of daily wearable sensors. The success of this key study led the same team of researchers to launch the DETECT Study in the face of the coronavirus outbreak. DETECT is an app-based research program that will analyze participants’ wearable health data to detect early signs of an immune response. Understanding important health metrics such as heart rate, respiration rate, body temperature, blood pressure, sleep, and others can provide first insights into potential immune infections days before any noticeable symptoms are reported! Emerging research shows that 30%-40% of patients with COVID-19 are asymptomatic yet still contagious, so we need more usable data besides the traditional approach of using body temperature.
And the secret to tapping into your healthiest self may be on your wrist everyday. You just have to know what you’re looking for.
One of the most basic, yet misunderstood, vital signs is heart rate. Heart rate is expressed in beats per minute (bpm). An optimal resting heart rate (RHR) is between 50 – 70 bpm. However, just like every health metric, RHR is completely individualized from person to person. Any perceived internal or external stressors will elevate your RHR – such as infection, dehydration, or poor sleep. Even early stages of illness increase physiological stress on the body which typically manifests as an overall increase in RHR, and can be detected hours or days before the onset of other symptoms. Elevation in RHR is also a typical physiological response during fever as the body begins to mount a defense to infection.
Be mindful of your average RHR. If you usually run between 51-55 bpm on most days, then begin noticing an elevation of your RHR into the low 60s or 70s and is accompanied by fatigue, changes in appetite, or disruptions in sleep, it could be early signs of an immune response.
HEART RATE VARIABILITY
Heart rate variability (HRV) is a health metric gaining attention of many fitness professionals to assess their athlete’s recovery capacity. HRV is measured as the average time difference between heart beats, or the ‘R-R interval’ as read on an EKG tracing. A lower HRV score indicates that our “fight or flight” central nervous system is activated due to a presence of increased physiological stress – such as high intensity exercise, undereating, poor sleep, or an immune response.
Measurement of HRV was added to Garmin devices in 2017, and is also featured in products like Oura ring and Whoop. A significant decrease in HRV score should be an indicator that it’s time to take a break, either from a work/life situation or scale the intensity back in your training to allow your body time to rest & recover. If you notice a decrease in your HRV score, but haven’t significantly changed your routine, it may indicate stress coming from an immune response mounting. While there is a lack of clinical evidence on the predictive value of HRV for viral illness detection, there is a large amount of self-reported and anecdotal evidence which leads us to hypothesize that HRV trends can be used to predict the onset of illness.
Respiration rate (RR) describes how often you inhale and exhale in a minute. It is also a primary vital sign along with heart rate, blood pressure and body temperature. Resting RR are typically between 8-15 breaths per minute. Elevations in your RR could indicate signs of perceived stress – either internal or external – and are cause for questioning.
Respiration rate (RR) is of critical interest when looking to identify early signs of viral respiratory diseases. These viral infections cause inflammation of lung tissue, coughing, and shortness of breath, which reduces the overall efficiency of the lungs and results in an increased RR to compensate. Baseline resting of respiration rate can be measured in a seated / resting position, or during sleep using a wearable like Whoop or other brands. Note your typical RR and be mindful of any elevations from normal.
Sleep is a complex and multidimensional subject that involves a range of essential recovery & restoration processes for the body & brain. Through the detection of micro-movements using accelerometer technology within a fitness tracker, many wearable units can capture when the wearer is sleeping and how much sleep they get each night. In the morning, the wearer will see a detailed breakdown of their previous night’s sleep, such as overall sleep duration, distribution of time in various of sleep stages (i.e. REM, light, deep sleep), how long it took to fall asleep, the number of awakenings during the night and others.
Specific sleep duration and patterns are highly subjective, and what works well for one person may not work well for another. There are days when you wake up after 6-7 hours of sleep feeling great, and there are days when 8 hours don’t feel like nearly enough. Some people tend to recover faster or slower than others and require more or less sleep to achieve the same benefits. However, we know that consistent sleep is associated with better health outcomes, performance, and longevity as it is very closely tied to our autonomic nervous system. The goal is to uncover what goes into a good night’s sleep for you, personally.
The key is to notice deviations from normal. For example, an increase in sleep duration paired with a decrease in sleep quality (i.e. less deep sleep, more times awakened in the night, etc) would be expected to occur when the body is mounting a potential immune response to infection. A downward trend in sleep scores may be an early symptom to recognize!
PUT THE POWER OF DATA TO WORK FOR YOU
There are many other useful health metrics to be aware of such as blood pressure, blood glucose, oxygen saturation, and more that can be tracked daily for useful health data. But don’t overwhelm yourself with fitness trackers and smartwatches – these are simply tools and the most important part is that you know how to interpret what you’re tracking. So where should you start?
Choose a fitness tracker, smart watch or other wearable device that suits your basic needs and preferences and begin wearing it consistently everyday to learn your baseline metrics. Use the data to become more in tune with how your body operates and feels. Once you know your ideal baseline metrics like average resting heart rate, average sleep quality, and estimated recovery scores, you will be able to easily identify when one or more metrics is “off” and take immediate action.
Discover how your body responds to life’s challenges. Whether it is early signs of getting ill or simply just how you respond to changes at work or family life, it’s important to identify key moments of stress and rest throughout the day and how you can better manage stress day-to-day.
Use these metrics as a guide to make better informed health and lifestyle decisions. Do you find that an extra cup of coffee in the afternoon jacks up your resting heart rate? Try going without it! Do you notice that the mornings you prioritize a healthy breakfast lead to better recovery scores? Keep that up! Maybe a few too many weekend adult beverages destroys your sleep? Scale back.
No one should know your body better than you, and with the help of technology, we can be our best health advocates in a time where preventative & proactive care is needed the most.