How do MvBii trackers measure activity and balance?


Our trackers use your motion to estimate the level of physical activity you're doing. Virtually all trackers do the same.  We use this to produce an average activity level every 15 minutes which is on a scale from 0 (not being worn) to 15 (very active). This scale is similar to a scale used in measuring physical exertion known as METS. 

From this data we can then work out what time you have spent at certain activity levels and give you some times per day to track how much of each type of activity you are doing. We use three boundaries: rest, moderate activity (light work or walking), and higher activity (brisk walking, jogging). You can use these times as a target (like the well known 30 mins exercise a day) to be more active.

We provide you with an activity target measure as well. This uses the activity scale and counts the time you spend (in 15 min chunks) above a certain level to fill up the target.  In normal mode (set from the app), the lowest level we count as activity is 3 which is broadly equivalent walking. In Sport mode it is 5 which is very vigorous walking or jogging.

Its worth bearing in mind that as the tracker measures motion it can (as with all trackers) be fooled by excessive movements of the wrist, or the other way round - we recommend you wear the tracker on your non-dominant hand (the one you don't write with), or if you do activities which use more lower body movement (walking or cycling) carry it in your pocket or on your belt. The key thing to remember is if you consistently wear it in the same way, the relative comparison day to day will also be consistent.  


We estimate calories by using something called your Basal Metabolic Rate (the calorie energy you burn simply being alive) and then using the activity level to work out what extra calories your activity is causing you to burn.  Again, as with all trackers it's an estimate because to know for sure you have to measure how much oxygen and CO2 is going in and out of your body! To be as accurate as possible it's important you use the app to set your age, sex and weight. 


Balance is not an absolute measure - it's meant as a personal prompt for you. You will need to learn how it adapts to your typical activity pattern and then it will become easy to spot significant changes. The concept is all about the rhythm of activity and uses time of day and the pattern to either push your balance towards a rest or exercise deficit. You can then use this as a prompt to decide if you want to take some action. For example - overnight you will see the balance level usually restores back to being close balance (100%). If you don't wear the tracker to sleep in, we do have to assume you have slept! If you work in an office and in the morning sit at your computer for a long time you will see your balance moves to an exercise deficit. If you take a break and have a walk for 10 mins for example (I know this may depend on how mean your boss is!) you will see the balance swing back.  If you're active for longer the rate of recovery will slow a little and if you're on the go for a long time it will move into a rest deficit. Using the diary annotations to make notes is a good way of helping if you want to make a change in how your day to day patterns are and how they make you feel. You can look back at how what you did (alongside things like what and when you eat), made you feel. 

One quick way of watching balance is to look at the colour of the balance stone on your tracker - if it's becoming pale it's nudging you to do some activity or take a break - if it's getting darker - think about a rest of doing some relaxation exercises.

The science of balance is only just emerging so expect us to be adding to this area in the future and be sure to keep up-to-date with our app updates.

My z-Track time display isn't on all the time

This is intended - we only display time for a few seconds when you lift the tracker up and hold it flat and steady (like you would when looking at a normal watch) to save battery power.  Mostly the display will be off but you should see a 5 second "heartbeat" flash of the 12 O'clock LED to show you the tracker is working. If you leave the unit overnight on a bedside cabinet we will even stop flashing the LED after a while to avoid keeping you awake! - It should start flashing again as soon as you move the tracker.  

My z-Track only connects to the phone/pad for a short time period

This is intended - we only connect to the phone long enough to transfer data to the app to save battery life on both devices.  If you have selected standard user mode (the unit ships with this selected), once connected it will transfer data and then shut down. In advanced user mode (set using settings screen on the app settings/my tracker), you can set longer times if you want to use the tracker to control your music player (default is 15 mins). 

The time on my tracker is wrong and the app doesn't show my activity data

This usually means the BluetoothTM link to the phone or Pad isn't working.

Check the phone or tablet Bluetooth is enabled and the tracker is charged.

The tracker must be on (done using a half roll gesture) to connect.

If you have done all this and are still seeing the issue you may need to repair the pairing on your phone or pad.

Go to the Z-Track section and select downloads to find an instruction note on how to do this.

My tracker won't switch on

Usually this means the unit battery is too low and the tracker is hibernating. Try connecting  it to a USB charger for a while (usually 2hours from flat).

My z-Track or z-ZAP won't pair with my app

Make sure Bluetooth is enabled and your phone device supports a specific type of Bluetooth known as Bluetooth SMART. Check with the shop or internet if you are not sure.

The tracker cannot pair to a phone unless the tracker is switched on  - see the quick start guide or the pairing video on how to do this.

If the tracker has been already paired with another Bluetooth device it can fail to pair. To solve this you need to repair by resetting the unit using a pin or paper clip.

Go to the Z-Track section and select downloads to find an instruction on how to do this.


How safe is MvBii messaging?

Our messaging is a private messaging system intended for a few close friends. You cannot search and find people to try to connect via the internet like bigger social media platforms. To make a group you need to be told the specific username by the person who knows it and you will only receive messages from users who are in your group. You can also delete group members from your group privately. As with all internet based systems supervsion of younger users is a sensible precaution. 


Sometimes my tracker doesn't recognize gestures

Our gestures are definitely a learnt skill so you will need a little patience to get them. The key thing to remember is that the starting point for any gesture is time showing on the unit, which is achieved by holding the tracker horizontal and steady. It can be harder if you're walking and if you're really moving you may need to slow down. The tracker does adjust its thresholds to account for movement - so for example the music shuffle shake requires more force when you're running than if you are sat still, but in this case you do not need to start with time showing. Gestures need steady not violent or rapid movements so patience is the key. 

Can I swim or bathe with my tracker?

No, z-Track and z-ZAP units are not  waterproof and may be damaged if you do - in normal use when fitted in a holder (like the diamond strap) the unit should withstand splashes and rain.


What does the balance colour mean?

When you set up your tracker you select a favourite colour to set the centre zone of the unit to - we call this the balance stone. During the day a clever algorithm in the unit looks at activity patterns and other things and changes the intensity of the colour - it is vibrant when you have had a reasonable balance of rest and activity, becomes pale if for example you are sitting for a long time, and becomes darker if you are active. We dont propose this is a scientific thing or medical measure- we can't tell if you are feeling ill or well,  or even if your cat's just died - but it can act as a means to prompt you to think about what you have been doing in a day and if you should think about taking a break or being more active. The diary function allows you to make notes at specific times for this reason.


Can I be tracked by my z-Track or z-ZAP?

No. One of the key things about our trackers is you decide when to switch it on so it wont be detected when it is off. The range of the tracker is small (a few 10's of meters) so again when it is on,  anyone trying to detect it needs to be virtually in eyesight of you. Our units wont pair with any device other than the one you paired it with so no one can read your data. 

How do I pair my tracker with a new tablet or phone?

Before you can pair a tracker which has already been paired to another phone or pad you need to reset it. See the how to guide section. 

Go to the Z-Track section and select downloads to find an instruction on how to do this. 

What is Paced Breathing

Paced breathing is a relaxation exercise.  You can use the tracker display or the app to use it.

The idea is to concentrate on the display pattern and your breathing for a short period (say 5 mins) to give your mind and body a fast but effective break from busy lives.


Only do paced breathing where its safe and secure for you to relax. You should be sitting down and not operating any machinery.

If you feel uncomforable at all doing the exercise STOP.

If you have any medical condition which may be affected by breathing exercises (cardio respiratory issues for example) talk to your doctor before doing it.

Can I change straps or accessories after I bought it?

Yes - the main electronics unit is intended to be removed and swapped over by users as they wish. You dont need tools to do this.

How often do I need to connect to the app?

Our tracker stores its data for several days so don't worry that you need to connect it frequently - you will need to charge it more often than this. When it connects to the app (when its switched on and connected), it will transfer data to the app so you should see the app data sync up.  We would recommend you connect it at least once a day however - mainly because you will get more out of it then, but also because it sync's its time with the phone or pad and it means the time will be as accurate as possible.

The time on my tracker isnt correct ?

When the battery goes really flat it can loose the time setting. Recharge the tracker and connect to the app - the time should sync to the phone's time.

How do I understand how to use all the features fully?

See the full user guides in the downloads sections of each product type.