Frequently asked questions

Moodmetric / Technology / Frequently asked questions

Smart wristbands, smart watches and smart rings measure physiological signals. Most of the technology is centered on measuring heart rate or heart rate variability. All the trackers have at least one accelerometer which is used for, for example, counting steps.

The Moodmetric smart ring measures electrodermal activity. It is designed to measure stress levels based on the activation of the sympathetic nervous system. Stress can be triggered both by negative (anxiety, irritation, frustration, fear etc.) and positive (enthusiasm, excitement) emotions and reactions. The Moodmetric smart ring can be used for long-term monitoring, or for the detection of single reactions in real time.

The ring helps the user to understand their psychological (emotional and cognitive) load better. For example, intense emotions and demanding math tasks easily raise stress levels.

The Moodmetric smart ring measures electrodermal activity 24/7. The ring is therefore suitable for measuring stress and recovery both day and night. So, to improve your sleep, the Moodmetric smart ring helps you to analyse what causes stress during the day.

Physical activity or sudden peaks in stress levels do not affect the overall average MM levels. The results can be viewed on the app anytime of the day.

The Moodmetric smart ring measures skin’s electrodermal activity. High Moodmetric levels tell about positive or negative stress and low levels about calmness or tiredness.

Electrodermal activity (EDA) tells about the activation of the sympathetic nervous system. Other terms used are galvanic skin response (GSR) and skin conductance (SC).

The Moodmetric smart ring measures electrodermal activity with an accuracy of a laboratory device. The Moodmetric algorithm computes an easy to interpret index on a scale of 1-100.

The Moodmetric index is robust to motion. The index is comparable among users.

The Moodmetric smart ring is not only a tool suitable for personal stress management, but appropriate for field research too.

The practice of measuring electrodermal activity is widely in use in psychological studies. The activation of the autonomic nervous system can be measured from skin conductivity.

An immediate and strong reaction by the autonomic nervous system (ANS) is the so-called fight-or-flight response: a person sees, hears or experiences something that requires instant action. This reaction is unconscious and in the early times of human history reserved for life-threatening situations.

Today many people are continuously in a heightened state of alertness – they experience stress. Also positive stress can wear a person out when it keeps them active for long periods of time, without proper recovery taking place.

The quality of the Moodmetric measurement has been researched in two independent studies. In both the accuracy and precision of the signal was found to be close to that of laboratory research equipment (Torniainen, 2015) (Pakarinen, 2019).

According to these studies, the Moodmetric smart ring is valid for research. It is also a reliable tool for personal well-being.

Read more about the measurement accuracy >>

Measuring skin conductivity requires a high density of so-called eccrine sweat glands. For this reason and for the most accurate results, measuring has to happen on the palm of a hand, finger, or sole of a foot.

The measurement accuracy is optimal when measured with a ring.

No, the measurement does not assess the emotion the wearer is experiencing, only the strength of the reaction. The diary feature in the Moodmetric app gives the wearer of the ring the possibility to determine if their mood is positive or negative in relation to a certain event.

The ring is meant to be personal. It has a self-learning algorithm that adjusts to one user in the first 12 hours of the ring being worn.

When changing from one user to another, there is a calibration time that needs to be considered: During the first hours, measurement results tend to be closer to the median (50) than later on.

Having said that, the ring can be used for short periods of time by several users in, for example, group testing circumstances. In such cases a calibration time of at least 30 minutes should be allowed, during which the wearer should try to experience sensations of both relaxation and intense excitement. This enhances calibration and makes the test results more accurate.

The Moodmetric measurement result range of 1-100 is defined by an algorithm that adjusts to the wearer of the ring. In practice this means that the lowest possible level (1) is reached in deep sleep, and the maximum (100) when experiencing, for example, a sudden and profound threat. When the ring has been measuring at least for several hours, the maximum and minimum values for the wearer have been detected and set as personal limits.

After this the measurement results are accurate and always show the typical levels for that particular user. Calibration is complete at the latest once the first 24 hours of measuring have been reached, if not sooner.

Adjusting is begun by pressing Calibrate in the Moodmetric mobile app. The ring needs to be worn at this stage, as otherwise the app does not detect the ring and calibration can not be done.
The ring should be calibrated for a user only once, as doing it again would restart the process of adjusting from the beginning and make previous and new data incomparable.

Note: When pressed, the Calibrate button in the app turns red for a second on phones running Android, and pale or grey on phones running iOS. This might go unnoticed. To confirm that calibration has been successfully executed, you return to the home screen of the app to see the MM level 50 beginning to change.

Yes. The Moodmetric index learns the baseline of the user and gives 100 for the detected maximum reaction and 1 for the minimum. The lowest reaction typically occurs in deep sleep and maximum in a very exciting or frightening situation.

When two persons each have their app showing 100, they are both in their maximum alertness level.

No. The ring is a standalone device and stores the data in the memory of the Moodmetric smart ring. The data can be downloaded whenever you open the Moodmetric app and tap the calendar icon.

The Moodmetric smart ring stores data up to 24 hours. However, it is advised to download the data from the ring to the app a few times a day for the most successful data transfer.

You get the most out of the Moodmetric data when you use the ring day and night.

You can choose to conduct measurements also periodically. In this case, it is good to note that the battery may be discharged. Always charge the battery before taking the ring into use.

No. The bluetooth connection has to be on only when downloading the data from the ring to the app, or when viewing the real-time Moodmetric level.

Note: If bluetooth on the phone has been turned off, it is advisable to refresh the connection between the ring and the phone by taking these steps:

  • Go to the app, Select ring and choose your ring
  • Make sure that the phone is connected to the ring by viewing what reads on the bottom left of the screen: ‘Forget’ means that the connection has been successful, ‘Connect’ that you need to press Connect again to try and establish the connection.
  • On some Android models, you need to reconnect each time you open the Moodmetric app. Go to your phone’s bluetooth settings and select ‘remember this device’.

The Moodmetric smart ring is available in five sizes:
XS (16 mm / US 5.5)
S (17 mm / US 6)
M (18.5 mm / US 8.5)
L (20 mm / US 10)
XL (21.5 mm / US 12)

The ring can be worn on any finger. It can also be changed from one finger to another. For example, it is recommended that at nighttime you put the ring on a finger where it feels loose, because fingers normally swell a bit during sleep.

Note that finger sizes vary between your left and right hand.

The right size can be found by measuring the inner diameter of an existing ring or using a sizing chart, for example

You can wear the Moodmetric smart ring on any finger. Note that fingers are usually of different size on different hands.

Temperature variation affects the thickness of the fingers.

You can change the ring to another finger at any time.

Fingers tend to swell during the night. It is a good idea to put the ring overnight on a finger where it feels loose.

Cold temperatures can also reduce blood circulation in fingers, causing the ring to become loose and impacting its ability to give a consistent reading.

No. The ring is splashproof and should be removed when coming in direct contact with water, such as when washing hands, taking a shower, or swimming.

Sweating will not harm the ring, so you can wear it while doing heavy exercise.

Remember that the ring is not waterproof and you need to take it off e.g. when washing hands. Also excessive use of hand lotion or desinfectant might damage the ring. If the ring gets wet, wipe it dry immediately.

If the measurement signal does not appear on the Moodmetric app, or the app does not find the ring, check the following:

  • The bluetooth of your phone is turned on
  • The location services are turned on (Android)
  • The Moodmetric smart ring is charged
  • The phone’s battery level is at least 20%
  • Your ring appears on the Select ring view of the Moodmetric app
  • If your hands are very dry, try adding some moisturizer for better skin contact
  • Cold hands or a ring too loose can cause poor skin contact

If the problem still persists,

  • Make sure that the phone is connected to the ring. Forget on the main view of the Moodmetric app means that the ring is connected to the phone, Connect that you need to press Connect again to try and establish the connection.
  • Shut down the app and open it up again
  • Plug the ring and lightly touch the band and while doing so, try to find the ring with the app (the ring signal is stronger when in charger)
  • Try to turn the bluetooth off and back on again
  • With Android phones it can take some time to form a connection, even up to one minute.
  • If location services have been turned off, you might need to restart the phone (Android).
  • On some Android models you need to reconnect each time you open the Moodmetric app. Go to your phone’s bluetooth settings and select ‘remember this device’.

Android devices require that location services are turned on. iOS devices do not require this. Moodmetric does not use location data for anything other than creating the connection.

The Moodmetric app works on iOS and Android phones.

Note: With some Android phones establishing the connection might be very slow.

Read about data interpretation here.

Chronic or acute illness

A serious medical condition often affects the autonomic nervous system, resulting in either very high or very low Moodmetric levels. The same goes for medication and other treatments (see below).


All strong medication, but especially central nervous system agents, affect the balance of the autonomic nervous system. This might result, temporarily or permanently, in abnormal MM levels.