My sleep score has always been the first metric I check when I wake up each morning, but that’s changing as wearables shift focus to a new rating: the circadian score.
Picture the scene: you got at least seven hours of sleep last night and your sleep score was high, but you're still exhausted. The issue might have nothing to do with your quality of sleep and everything to do with your internal body clock.
A growing body of sleep tech recognizes this gap, moving beyond simple sleep scores toward circadian scores—a whole-picture metric that evaluates your 24-hour biological rhythm. Instead of just tracking time in bed or each stage of sleep, a circadian score factors in how daily habits like morning sunlight exposure and evening meal timing impact your rest.
Here, I'll explain how monitoring your circadian score can help you fall asleep faster, wake up with more energy, and optimize your schedule. Plus, we look at six trackers leading the circadian health trend.
Key takeaways: At a glance
- Your circadian rhythm is a 24-hour body clock that regulates sleep, depending heavily on light exposure and habits.
- A sleep score is how you slept (duration, deep/REM sleep, night awakenings)
- A circadian score is why you slept that way (consistency, morning light exposure timing and duration, and timing of evening meals, etc).
- Leading sleep trackers that offer circadian scores, including the pre-order Rhythm Ring, the Ultrahuman Ring AIR, and the Circular Ring 2.
What is a circadian score?
To understand what a circadian score is, let's recap on what a circadian rhythm is. Depending on light exposure, our circadian rhythm acts as a 24-hour body clock that regulates sleep, hormones, temperature, and digestion to keep body processes synchronized with day and night.
Dr Nisa Aslam, advisor to Evera Nutrition, explains that our circadian rhythm is regulated heavily by the sleep hormone melatonin, calling it a "time keeper".
Dr Aslam continues: "It is produced in response to darkness, begins rising in the evening and then under normal conditions peaks at approximately 3:00am before declining towards morning.
"Its role is to signal when to sleep, not necessarily how deeply to sleep."
“Melatonin plays a central role, but restoring circadian rhythm requires more than a single hormone, it involves a balance of light exposure, behaviour, and neurotransmitter support,” he adds.
According to the health expert, irregular sleep schedules, artificial light, and travel can disrupt this balance, "making it harder to wind down".
So, a circadian score measures how well your daily routines strike this balance, aligning your sleep schedule with your circadian rhythm.
For example, studies show that exposure to sunlight in the morning can regulate your circadian rhythm, while research suggests that eating too close to bed can goes against your natural body clock.
Why circadian scores are dethroning sleep scores
While sleep scores tell you how you slept (for example, for how long you slept and how many nighttime awakenings you experienced), it can't tell you why you slept that way. A circadian score can give you key insight into how your daily habits are affecting your sleep quality.
For instance, going to bed at different times every night may be why you find it hard to fall asleep, or maybe a late night workout may be causing sleep disruptions.
6 wearables that track aspects of your body clock
1. Rhythm Ring
If you're looking to find out how late nights or an irregular schedule are affecting your sleep, then the pre-order Rhythm Ring (which you can now reserve for $1) is worth considering.
It's designed specially for shift workers (the first of its kind to do so), where erratic work hours lead to fragmented sleep.
The wearable offers a Circadian Score (rated on a scale of zero to 100) to tell you how well your natural light exposure matched your schedule that day.
2. Ultrahuman Ring AIR
The Oura Ring-rivalling Ultrahuman Ring AIR is a sleep-tracking smart ring, and with no subscriptions necessary you can now buy the Ultra Ring Pro for $479 via Ultrahuman.
The smart ring has a dedicated Circadian Phase Alignment Clock, which maps your body’s Phase Response Curve (PRC) to show where you are in your circadian cycle and gives real-time nudges for light exposure, exercise, and caffeine cutoff windows.
3. Circular Ring 2
The Circular Ring 2 is a smart ring (notice a pattern, here?) that tracks health, fitness and sleep, and it starts at $379 at Circular.
It uses an internal AI assistant (Kira) to track a sub-metric of its overall sleep score. This sub-metric scores your Circadian Rhythm (or rather how your sleep and activities align with it).
4. Oura Ring 5
I have an Oura Ring 5 (now $399 at Amazon) and the sleep tracking is excellent. While it doesn't provide a circadian score per se, it does rank how your sleep timing aligns with your own personal circadian rhythm.
While I'm still in the early stages of wearing my Oura Ring, once I've consistently worn my smart ring for 90 days, I'll be able to unlock the Body Clock feature to help optimize my daily schedules based on my sleep chronotype.
5. Withings
If you don't enjoy wearing sleep trackers to bed, the under-the-mattress Withings Sleep Analyzer, now $199.95 at Amazon) is perfect for tracking your sleep schedule.
While it doesn't provide a standalone circadian score, it factors a Regularity score directly into the overall Sleep Score calculation.
By continuously monitoring bedtime and wake-up consistency night after night, the mat highlights how well-synced a user's sleep habits are with their biological clock to help optimize their overall rest
6. Garmin
Now $169.99 at Amazon, the Garmin Sleep Index Monitor has circadian monitoring feeds into Sleep Alignment metric, which rates how closely a person's sleep schedule matches their underlying biological clock.
While the armband wearable starts logging core recovery metrics right away, once it tracks skin temperature and sleep patterns over a few weeks, it generates personalized guidance to help align daily routines with natural circadian rhythms.
How to improve your circadian score
Using a wearable to track your body clock is Act 1 – the exciting part happens when you use all that data to adjust your daily routine.
Here are four lab-tested, expert-vetted habits to boost your circadian score:
- Get morning light within 30 minutes of waking: Ideally step outside for this, as the sun contains natural blue light to wake you up and signal to your circadian rhythm that sleep is over and its time to be productive.
- Aim for the same wake-up time every day, even on weekends: Your rise time is more important than the time you go to sleep. Consistency is important, as varying your wake-up time from day to day can cause 'social jetlag'. This confuses your internal body clock and puts your sleep quality in the toilet.
- Switch to dim lighting around 60-90 minutes before bed: Bright, stark, artificial overhead lighting tricks your brain into thinking its daytime. Dim lighting boosts production of melatonin, a master sleep hormone.
