Fitbit Charge 2: Sleep Tracking And More

The Fitbit Charge 2 is a multisensor fitness tracker that can monitor your sleep. It can track your sleep patterns, including the time spent awake, restless, and asleep. It can also monitor your heart rate and track your time in light, deep, and REM sleep. The Fitbit Charge 2 is water-resistant and has a battery life of up to 5 days. To track sleep, the device should be worn higher on the wrist, and its sleep tracking features include bedtime reminders and silent alarms.

Fitbit Charge 2 accuracy

The Fitbit Charge 2 can track sleep. It monitors heart rate activity through a patented PPG technology called PurePulse, which counts steps, calories burned, and tracks sleep activity. The Fitbit app allows users to understand their sleep patterns and quality. The time asleep is calculated by subtracting the time spent awake and restless from the overall tracked sleep time.

The accuracy of the Fitbit Charge 2 has been assessed in several studies. One study found that the Fitbit Charge 2 underestimates heart rate, with a mean bias of -5.9 bpm and wide limits of agreement (+16.8 to -28.5 bpm). This indicates that an individual heart rate measure could be underestimated by almost 30 bpm. Another study compared the Fitbit Charge 2 to a gold standard electrocardiograph and found an ICC of 0.21, suggesting low agreement between the two methods.

User experiences with the Fitbit Charge 2's accuracy have been mixed. Some users have reported that the device accurately measures heart rate at rest, but there can be discrepancies during physical activity. For example, one user found that their heart rate was accurately measured while simultaneously taking their pulse, but noticed a lag during workouts. Additionally, some users have questioned the accuracy of the heart rate monitor, with one user reporting that it detected a heart rate even when not being worn.

It is important to note that the accuracy of the Fitbit Charge 2 may depend on various factors, such as skin characteristics, BMI, and age. While it can provide insights into sleep patterns and heart rate, it is not intended to diagnose or treat any medical conditions and should not be solely relied on for medical purposes.

How to track sleep with Fitbit Charge 2

The Fitbit Charge 2 has a robust sleep-tracking function. To track your sleep with the Fitbit Charge 2, you simply need to wear it to bed. The device will automatically start logging your sleep once it recognises that your body is going into sleep mode.

The Fitbit Charge 2 will monitor your sleep by tracking your sleep stages and heart rate. It will record the amount of time you are asleep, as well as the quality of your sleep. The device will detect restless sleep through the way your body moves. If your Fitbit detects excessive movement, it will record this time as being awake.

To accurately track your sleep, make sure your device is positioned higher on your wrist, about 2-3 finger widths above the wrist bone. The band should feel secure but not too tight.

You can sync your device each morning to review your sleep data, such as your sleep score, in the Fitbit app. The app will show you the number of hours you slept each night and your weekly average. You can also see your sleep score and weekly average score. You can toggle between 'Hours Slept' and 'Sleep Schedule' using the buttons under the charts.

If you have a Fitbit Premium subscription, you can get a Sleep Profile. This provides a detailed sleep breakdown that is available on the first of every month. This breakdown includes 10 monthly metrics and also features a sleep animal that characterises your long-term sleep behaviours.

Fitbit Charge 2 battery life

The Fitbit Charge 2 has a battery life of around 3 to 7 days, depending on usage. Some users have reported that the battery life of their Fitbit Charge 2 decreased over time, with the battery lasting only 2 to 3 days before requiring recharging. The device takes around two hours to charge.

It is worth noting that the battery life of the Fitbit Charge 2 may vary depending on various factors, such as the age of the device, usage patterns, and the condition of the battery. While some users have reported using their Fitbit Charge 2 for 5 to 6 years, others have mentioned that the battery life decreased significantly after a few years of use.

To ensure optimal battery performance, it is recommended to follow the manufacturer's guidelines for charging, usage, and storage. Additionally, regular software updates may also help improve battery life, as Fitbit may release updates that optimize the device's power consumption.

It is also important to note that certain features of the Fitbit Charge 2, such as the heart rate sensor, may consume more power and impact the overall battery life. Users who prioritize longer battery life may consider disabling certain features or adjusting the settings to extend the battery life of their Fitbit Charge 2.

Fitbit Charge 2 sleep tracking features

The Fitbit Charge 2 can track your sleep patterns and quality. It can also track your heart rate all day and during exercise. To track your sleep, you should wear your Fitbit Charge 2 to bed. The device will then record your sleep pattern, including your time spent awake, restless, and asleep. The Fitbit Charge 2 will also track your heart rate during sleep, which can be used to determine the sleep stages you cycle through. These sleep stages include light sleep, deep sleep, and REM sleep.

To get the best results from the Fitbit Charge 2's sleep tracking features, it is recommended to wear the device higher on your wrist, about 2-3 finger widths above your wrist bone. The band should be secure but not too tight. Additionally, you can set bedtime reminders to help maintain a consistent sleep schedule. The Charge 2 will prompt you to unwind 30 minutes before your bedtime target. You can also set silent alarms to wake you up in the morning or alert you at a certain time of day.

The sleep data recorded by the Fitbit Charge 2 can be synced and reviewed in the Fitbit app. This includes your sleep score and the number of hours you slept each night. You can also check your averages for the week or longer periods of time for certain sleep stats. The Fitbit app also allows you to manually adjust your sleep data and set sleep reminders.

It is important to note that the Fitbit Charge 2 is not intended to diagnose or treat any medical condition, and you should consult your healthcare professional for questions about your health. The sleep tracking features of the Fitbit Charge 2 can provide insights into your sleep patterns and quality, but they should not be relied upon for any medical purposes.

Fitbit Charge 2 sleep tracking limitations

The Fitbit Charge 2 can track sleep and heart rate. However, it has some limitations. Firstly, it is not intended to diagnose or treat any medical condition and should not be relied on for any medical purposes. Fitbit recommends consulting a healthcare professional for any health-related questions.

Secondly, the Fitbit Charge 2's sleep staging algorithm may not accurately treat REM and deep sleep states of less than 4.5 minutes, introducing a non-biological discontinuity. This indicates the potential limitations of the tracker's staging algorithm. Additionally, the PSG measurement corresponding to the "restless" stage on the Fitbit is unclear, making meaningful comparisons challenging.

Thirdly, the Fitbit Charge 2 only provides 7.4 measurements per minute on average, which may lead to higher variance in PSG recordings. This is due to the algorithm averaging values in specific intervals, such as 5, 10, and 15 seconds. In contrast, a PSG-derived HR value can be computed for each IBI, resulting in more detailed data. Furthermore, the Fitbit's heart rate values are integers, while PSG values are real values, causing slight differences in the HR10 and HRvar10 measures.

Lastly, the Fitbit Charge 2's battery life is up to 5 days when fully charged, but this may vary depending on usage, settings, and other factors. Therefore, users should ensure the device is charged regularly to avoid interruptions in sleep tracking.

Frequently asked questions