am a terrible sleeper. I know this because my Withings Aura and Jawbone UP2 records how much time I spend in the land of nod and then displays it on my phone in the morning. I need to get more shut-eye. People talk about the three pillars of health (sleep, diet, exercise) and sleep is the one I rarely tick off the list. Getting the recommended 7-8 hours a night is tough.
But the fact that I am thinking a lot more about sleep must be a good thing. That doesn't mean the data still doesn't bamboozle me. What it does all mean? What can I do with the information? I needed to talk to someone who lives and breathes sleep data and I think I found that person.
Essential reading: Sleep monitoring explained
Kirstin Aschbacher is a data scientist who works as part of the data team over at Jawbone. Her recent analysis of sleep data from Jawbone users draws the link between restricting sleep and increasing calorie intake.
But there's other key insights I learn you can gain from analysing your sleep aside from knowing you're guaranteed to be napping on the way into work. "You might notice, for example, that you have a lot of awakenings during the night," says Aschbacher.
"Sometimes you get a larger amount of deep sleep or REM sleep than other nights. You might notice that this seems to be correlated with how you feel.
"You"ll be able to notice when bedtime is inconsistent, and how bedtimes may relate to steps or resting heart rate and other factors you can track. Users may notice patterns themselves, and that is part of the power of tracking your sleep."
More sensors, richer data
The large majority of fitness trackers including Jawbone, Fitbit and Misfit rely on an accelerometer motion sensor to detect movement. This can give you basic sleep stats, like hours slept or how long it takes you to actually fall asleep. As Jawbone tells us, this approach has not been formally validated to measure sleep, but can measure light/sound sleep and wake periods.
When you throw in extra sensors like a heart rate monitor, galvanic skin response and body temperature sensors however, then sleep monitoring can start to become more insightful.
"When your resting heart rate deviates (higher than normal), it could be linked to a poor night of sleep," Aschbacher explains.
"Lowering your resting heart rate is a big deal for determining your fitness level and cardiovascular health. Getting a full night's sleep is one way to improve it. But these extra sensors can go beyond that.
"Jawbone's UP3 tracker can detect, for example, that you woke up 8 times the previous night. Or the deviations could be due to dehydration."
Keeping the body clock ticking over
If you take your sleep tracking seriously then you'll know about Circadian rhythms. Better known as the internal body clock that tells you when to go to bed and can be affected by environmental changes. But how important is it to monitoring sleep?
Circadian rhythms encompass a lot of different factors and are definitely related to sleep," explains Aschbacher. "This is a big question, but in essence, the two are linked, yet not the same thing.
"However, we've done some research on our data in the past that has showed how the two relate. Our sleep can be shaped by daylight. In the US, on the westerns extremes of time zones, people tend to go to bed later, and on the eastern edges they go to bed earlier (for example, look at the Central Time Zone).
"The starkest difference can be seen on the Kentucky/Tennessee borders between Eastern Time and Central Time, splitting the states in half (pictured above). The average difference in bedtime across the time zone border is 16 minutes (excluding Hamilton County, TN, since it contains Chattanooga), and some places it's as high as 30 minutes."
Future of sleep monitoring
Interpreting sleep data is one of the greatest challenges faced by fitness trackers. Having that flood of data is great, but knowing what to do with it is where the real value lies.
Jawbone believes it's changing behaviour and features like its Smart Coach is helping users to understand it, know what to do with the information and then show how it can change their lifestyle in a positive way.
There's still a lot to learn about delivering truly meaningful data. Progress is being made though. Garmin introduced Insights earlier this year for its fitness trackers and running watches, while Under Armour is relying on its IBM Watson software to help users make sense of the data.
So what does the future hold for sleep tracking? How much more insightful could it become?
"There's a lot of future potential to deliver more personalised insights to a user about how sleep influences his or her behaviour," says Aschbacher.
"We know a lot about the links between sleep and behaviours at the level of groups of users. It is a harder problem, from a data analysis perspective, to tailor or personalise these kinds of insights for individual users.
"Jawbone has definitely already made significant strides in this area, and we anticipate being able to do more in the near future."
Jawbone is celebrating World Sleep Day by announcing its Sleep Day Challenge. You can find more info here.
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