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Apple Watch uncovered my toxic stress level, and helped me fix it

With Sleep Watch, HRV Tracker and Breathe on the Apple Watch, I was able to change the most unhealthy part of my life.

Jason Hiner VP of Content, CNET Labs; Editor in Chief, ZDNET
Jason is Vice President of Content for CNET Labs and the Editor in Chief of ZDNET. From CNET's world-class testing facilities, the CNET Labs team designs tests to quantify the best products worth buying.
Expertise Over 20 years of experience covering Apple, Google, Microsoft, Samsung, computers, smartphones, wearables, and the latest technology products. Credentials
  • Jason is an award-winning journalist, editor, and video host with a passion for covering cutting edge innovation.
Jason Hiner
7 min read

The Apple Watch's built-in Breathe app is an excellent way to begin a meditation routine.

Jason Hiner/CNET

When I started using the SleepWatch app on the Apple Watch  a year ago, I intended to mostly compare it to other sleep tracking products I had tried. But it led to a series of events that helped me not only quantify my sleep better than other sleep tech, but also identified a bigger issue: my unhealthy level of stress. Combined with a couple other apps on the Apple Watch, I was able to improve my stress and track my progress by following Heart Rate Variability.

It all kicked off last May when I started testing the SleepWatch app and a couple other sleep tracking apps on the Apple Watch. Part of my motivation was that reports had begun circulating that Apple was working on adding built-in sleep tracking to the Apple Watch. So I wanted to see if the Apple Watch actually had strong enough battery life to handle sleep tracking, if I minded wearing my watch while I slept, how accurate its tracking could be, and what kinds of data it could provide.

After testing the free versions of several sleep tracking apps. I gravitated to SleepWatch because it felt like the most polished, most detailed and the one that was most like a feature Apple would design.

Since CES 2018, I had been testing a number of different sleep technologies since sleep was one of the hottest new categories at the show that year. I also knew that of the three pillars of health -- nutrition, exercise and sleep -- sleep was the one where I needed the most help. I already had discipline and a good routine for exercise and nutrition, and tech played an important part in that. 

Read moreApple Watch saved my life: 5 people share their stories

I had been an early adopter of Fitbit in 2010 and switched to the Apple Watch to track activity when it launched in 2015. I had also been using apps like LoseIt to track my meals and daily nutrition for nearly as long. 

By early 2018, the tech industry had woken up to the fact that sleep was one of the next frontiers where technology could help improve lives. The CES Sleep Tech pavilion had all kinds of tech products aimed at helping people sleep, from special glasses to high-tech sleep masks to smart air filters to smart pillows to speakers for creating a sound blanket. 

The first product that I tried out for tracking sleep was EarlySense Live, when I was working on a story about how their under-the-mattress sensor was being used to monitor patients in hospitals as well as kids with asthma. It worked pretty well. It seemed to track my sleep correctly about 80% of the time and the app was pretty simple. 


The Apple Watch continues to add more health features over time.

Sarah Tew/CNET

A couple months after CES, I also got a Sleep Number 360 Smart Bed. It had some features that made it a terrific bed, like the ability to adjust mattress firmness and tilt so that my wife and I could each customize for our side of the bed. But the sleep tracking features weren't great. I only found them to be accurate about 50% of the time and the data visualizations weren't nearly as detailed as EarlySense. Several times a week the SleepNumber would miss tracking times when I slept, or would erroneously pick up extra sleeping hours when my wife rolled slightly to my side or the bed or the cat hopped onto the bed after I got up. 

All in the all, the best thing about SleepNumber's tracking was that you didn't have to wear anything, add anything or do anything extra. The best thing about EarlySense was its detailed data visualizations that showed quality of sleep, such as Deep Sleep, Light Sleep and REM Sleep. 

When I started using SleepWatch, I quickly found it to be far more accurate than either SleepNumber or EarlySense. In my personal usage, it tracked correctly about 95% of the time. Since the Apple Watch was on the body and directly tapped into heart rate, that appeared to make it much more accurate. 

Read more: We look back at five years of the Apple Watch

I didn't mind wearing the watch to sleep in as much as I thought I would, mostly because the Sport Band straps on the Apple Watch were pretty comfortable and so it wasn't distracting or uncomfortable. The Apple Watch battery life also exceeded my expectations. I found that if I charged it for two to three hours a day -- when I was in the shower, reading at night before bed or while I was a meeting during the day -- that was enough to get a full day's charge. 

All of that gave me the confidence to track my sleep every night and to trust the data I was getting back. So I set a goal of averaging at least seven hours of sleep per night. That made it like a game -- like getting 10,000 steps a day or closing the Activity rings on the Apple Watch. And within a few months I was able to change my habits and routines so that I went from averaging five to six hours of sleep per night to at least seven. 

Once I had improved the overall amount of sleep I was getting, I started to dig into the other metrics that SleepWatch was tracking to understand the quality of my sleep. While SleepWatch didn't track REM sleep like EarlySense, it did add a number of other indicators that went into daily SleepWatch score. These included Total Restful Sleep Time, Sleeping Heart Rate Dip, 7-Day Sleep Rhythm, Sleep Disruption Percentage and Average Sleeping HRV. 


The SleepWatch app showing very low HRV.

Screenshot by Jason Hiner/CNET

When you look at each of these, you can click into them and see how your 30-day average compares with other SleepWatch users. Once I got my sleep up to an average of seven hours per night, all of my numbers were in the top 70th to 90th percentile -- except for one, Average Sleeping HRV. And that one was really bad, in the lower 25th percentile (meaning 75% of SleepWatch users were scoring better than I was). 

To be honest, I didn't even know what HRV was. The SleepWatch app itself had a little bit of information built into the app. So, I read that, "Heart rate variability (HRV) is not the same as heart rate. HRV is a relatively new and growing area of health research. HRV may reveal information about your well-being that heart rate can't." It also said, "Health research suggests that higher levels of heart rate variability during sleep are associated with more youthful physiology, better sleep quality, and less mental stress." 

The app included a few tips to improve HRV: consume less alcohol (I don't drink), adopt a regular long-term exercise routine (I was already doing that) and practice mindfulness activities before sleep. 

While I regularly practiced prayer and meditation, I tended to do most of it in the early mornings. So I started researching more about HRV, along with how mindfulness, meditation and deep breathing could improve HRV. I learned that the Apple Watch had just started tracking HRV with WatchOS 4 in 2018. 

I also learned that HRV essentially takes the pulse of your nervous system. Another way to think about it is that it's measuring the impact that stress is having on your overall health and well-being -- something that's normally hard to quantify since lots of adults internalize things rather than acting out. 

The Average Sleeping HRV reading in my SleepWatch data was saying that I had a potentially toxic amount of stress in my life and I needed to do a better job of managing it.

I started listening to the audiobook Breathing: The Master Key to Self Healing by Dr. Andrew Weil and started trying out a bunch of meditation apps. I eventually began using Dr. Weil's 4-7-8 deep breathing technique before sleep and I settled on Simple Habit as my favorite meditation app. I liked that one because it was the most focused on reducing stress and improving sleep. It also had the most free content so I was able to use it for a couple months before giving my credit card to opt for the subscription. 


The HRV Tracker app lets you see the full day and show progress over time.

Screenshot by Jason Hiner/CNET

Basically, I started taking meditation, breathing and mindfulness as serious as my workout regimen. Gradually, my overnight HRV numbers started to improve in the SleepWatch app. But since I was focused on improving my HRV, I also wanted to track it a little more closely and not just while I was sleeping, so I also downloaded the HRV Tracker app. Sure enough, I started noticing that when I had a stressful conflict, confrontation or setback, my HRV reading would often bottom out. 

But the Apple Watch doesn't track HRV constantly, and I wanted a better way to take the pulse of my HRV manually. I learned that the Breathe app built into the Apple Watch automatically triggers an HRV reading, so I started using that to get my HRV at different times when I was meditating or breathing during the day. 

It didn't take long for me to realize that the Breathe app itself is actually a great tool for meditation, deep breathing and mindfulness -- especially when you slow down the "Breath Rate" in the Apple Watch settings to four breaths per minute. Now, I keep tabs on my daily numbers with HRV Tracker -- and not just my sleeping HRV. I regularly use the Breathe app for two-minute sessions throughout the day and I've mixed it in with my other deep breathing exercises and the short meditations I do from the Simple Habit app. 

Read more: 9 native Apple Watch apps you should be using

With that, I've been able to increase my daily HRV averages from the mid-20s to the low-50s. That's still not outstanding, but it's much more normal and it continues to improve. The whole process has also trained me to understand my body better. I now realize when certain signals in my body -- that I would have previously ignored -- are sending up red flags to tell me I need to take moment to breath a little and reorient my thoughts. It's been a solid quality-of-life upgrade.

Watch this: The Apple Watch has been life changing for these four people