I want to start this post by saying that I am a fan and avid user of Fitbit. For my personal use, I have had both the Fitbit Charge HR and Fitbit Blaze, and have been a member for over a year. We also have a large inventory of Fitbits in our lab that we use for research. Fitbits are great in helping motivate people to live more active lives. I’m not alone in thinking this. As of August 2015, Fitbit had 9.5 million active users, with a total of 19 million registered users. All of this being said, I fear that this new feature may encourage poor sleep habits.
In case you missed it, Fitbit recently implemented a new feature that will set a sleep schedule for you that will help optimize your sleep. Here’s how it works. It averages your total sleep time, wake up time, and bedtime over the last month and using this information makes a recommendation for you to set a rigid schedule. I played around with mine, and it told me that averaged about 8 hours of sleep, like to go to sleep around 11:00pm, and wake up at 7:30am. Once this schedule is set up, it tells me to start getting ready for bed at 10:30pm and sets an alarm for 7:30am. Essentially, Fitbit is trying to motivate me to stick to a strict sleep schedule.
At first glance this seems great, right? As we know, sleep is important for health. So, if their app is helping to optimize our sleep, this should in turn make us healthier? This is a great idea! There is one problem though. This rationale does not completely align with the current sleep literature.
Sleep timing regularity is important for our sleep and physical health because it synchronizes our physiological sleep drive and our circadian rhythms1. Having more sleep variability is associated with more sleep problems and daytime fatigue2. So yes, regularity is important. But…the current sleep medicine therapies only target regularity for wake up times3. This contradicts some popular media sleep hygiene recommendations that propose regularity for both bed and wake time (I’m guessing this is what Fitbit based their app feature off of).
So why do sleep medicine therapies (i.e. Cognitive Behavioral Therapy for Insomnia) only target wake up times? The answer is simple. You should only try to sleep when you’re tired! Imagine yourself in this scenario. You fear that you are suffering from insomnia; you are having trouble falling and maintaining sleep and are struggling with bad daytime fatigue. Your therapist suggests setting a rigid sleep schedule for both your bedtime and wake time (let’s say 11:00pm and 8:00am). So the following night you try to implement this. You start getting ready for bed around 10:30 and get into bed at 11:00. But then you realize you aren’t tired! What then? You’re tossing and turning in bed, worrying that the longer you stay awake, the closer you get to your scheduled wake up time. Then you worry some more that you won’t fall asleep, and you worry some more. See this potentially disastrous cycle?
Each day is different, and you may not be tired at the same time every night. Trying to sleep when you’re not tired may not only buffer treatment effects, but could also lead to worse sleep. Due to this, targeting only wake up times may be efficacious and does not have as much potential to disrupt sleep. Trying to sleep when you’re not tired is also a poor sleep habit, because over time it associates your bed as a place where you cannot sleep (click here for more information).
In sum, I believe that this new feature by Fitbit is misleading and may potentially create unhealthy sleep habits. However, the current literature on this topic still needs A LOT more work. My lab has a few ongoing projects that will hopefully shed some light on this topic, so stay tuned in the next few years for updates on sleep schedule regularity!
- Dijk, D. J., & Czeisler, C. A. (1995). Contribution of the circadian pacemaker and the sleep homeostat to sleep propensity, sleep structure, electroencephalographic slow waves, and sleep spindle activity in humans. The Journal of neuroscience, 15(5), 3526-3538.
- Dijk, D. J., & Lockley, S. W. (2002). Invited Review: Integration of human sleep-wake regulation and circadian rhythmicity. Journal of applied physiology, 92(2), 852-862.2. Dijk, D. J., & Lockley, S. W. (2002). Invited Review: Integration of human sleep-wake regulation and circadian rhythmicity. Journal of applied physiology, 92(2), 852-862.
- Morin, C. M. (2011). Psychological and behavioral treatments for insomnia I: approaches and efficacy. In Principles and practice of sleep medicine (pp. 866-883). Elsevier Saunders, St. Louis, MO.