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A sleep bracelet: what it measures and how to choose

A useful sleep tracker stays out of your way at night and explains in plain language how you are doing in the morning.

tri bracelet on a wrist at night

What the bracelet sees while you sleep

At night, the bracelet tracks heart rate, heart rate variability (HRV), movement and skin temperature. Together, these form a picture of your night: when you fell asleep, estimated deep, light and REM sleep, awakenings and how your heart behaved.

One night alone says little. Value builds after a week or two, when the bracelet knows your baseline. You can then observe patterns such as less deep sleep after evening coffee or higher resting heart rate after exercise.

What to consider when choosing

  • Comfort at night. A rigid case or screen that lights up when you move can disturb you. Choose a soft strap and no light.
  • Battery life. If a tracker needs charging every night, eventually you may forget to wear it and lose useful data.
  • Insights you can use. A hypnogram looks good, but in the morning you need to know whether you rested and what you can do.
  • An alarm on your wrist. Wrist vibration wakes you rather than the person beside you.
  • Language and payment. A Russian app and guidance, payment in rubles and direct access without workarounds.

How tri does it

Bracelet tri is designed to stay out of your way: fabric strap, no screen or notifications, and up to 15 days per charge. In the morning, the app shows a sleep score from 0 to 100, sleep stages and sleep debt: how much sleep you missed over recent days. Recovery appears alongside it, estimated from nighttime HRV, resting heart rate and breathing.

In the evening, the app suggests a bedtime to help you get enough sleep. Write ‘Wake me at 6:40 on weekdays’ to the assistant. It sets an alarm on the bracelet to wake you by vibration.

What the bracelet cannot replace

A consumer tracker is not a medical device. It helps reveal trends and habit patterns, but does not diagnose apnea or insomnia. If poor sleep persists for weeks, the bracelet can help you notice it; discuss the cause with a doctor.

Read more about routines and habits in articles on sleep routine, on when to go to bed and on your last coffee.

Questions

How accurately does the bracelet identify sleep stages?

Sleep stages are measured with polysomnography in a laboratory. The bracelet estimates them using heart rate, HRV and movement. This helps you observe your baseline and patterns related to coffee, alcohol or late workouts. It does not diagnose conditions.

Does the bracelet disturb sleep?

tri has a soft fabric strap and no screen. Nothing lights up or vibrates with notifications. Only an alarm you set can wake you.

Do I need to charge it every night?

No. It runs for up to 15 days per charge. Charge it during the day while you shower or work.

Can I sleep without my phone nearby?

Yes. The bracelet stores up to 30 days of data and sends it to the app when your phone is nearby.