To get the most of out of using a heart rate monitor chest strap device, it is important to understand the basics of how these devices work and what you can do to ensure they work as expected. This article references the M7, but the general content is true for all brands of heart rate monitors.
Here are some tips for using a heart rate monitor chest strap:
Fit:
The strap should be snug but comfortable, and shouldn't restrict breathing or movement. The M7 strap needs good skin contact. If the strap is too loose, it may move around when you’re training and lose skin contact.
We have two different strap sizes available. Strap size is chosen at the time of checkout during the purchase process but if you need an extra strap or a different size, you can get one at the appropriate link below.
Wearable size (XS-S): 20″ to 28″ (51 to 71 cm) with max stretch to fit 38″ (97cm)
https://eza.infusionsoft.com/app/orderForms/m7-replacement-strap-small
Wearable size (M-XXL): 24” to 36” (61 to 92 cm) with max stretch to fit 60″ (153cm)
https://eza.infusionsoft.com/app/orderForms/M7-strap-regular
Placement:
The M7 should be placed directly underneath the pectoral muscles with the sensor over the bottom of the sternum. Below represents how the M7 should be positioned for men (left) and women (right). Note that it is also acceptable for women to slide the M7 strap and transmitter under the bottom of a bra.
Note: Some people may benefit from shifting the transmitter slightly to the left instead of having it centered. This may place the electrode area of the strap closer to the heart.
Sensor Orientation:
In order to read accurately, the heart rate sensor must be snapped into the chest strap so that the Morpheus logo is right side up and could be read by someone facing you. This means when you snap the sensor into the chest strap, the Left snap should be on the left side of your body and the Right snap should be on the right. The back side of the sensor also has L and R next to the pins. The circular LED light on the front of the device will be on the left side of your body.
After you attach the transmitter to the strap, you will hear a single audible beep and the LED light will turn on and blink when it's been activated. It will blink a few times in a white color while searching for HR and then it will blink blue for 10 seconds after it has found solid HR signal. After that the LED will shut off, but the device remains powered on and active.
Moisture Pt 1:
Before training, you should always add either water or electrode gel to the rubber sections that cover the electrodes of the chest strap.
Put a fair amount water and/or electrode gel on the skin side of the strap on the rubber sections to the left and right of the middle. If you do this after you are already wearing the strap then it will be less likely to rub off and will also get on your skin where the strap touches. Electrode gel will provide the best contact possible, but water works well for most people. When you do this after you are already wearing the strap it prevents the water or gel from rubbing off as you put on the strap. In addition to this, you can put moisture on the front side of the strap in the same locations.
Moisture Pt 2:
If the environment you train in is cool and dry and/or you wear moisture-wicking training shirts, you’re less likely to have moist contact with the chest strap.
This means you may often get incorrect or sporadic readings, especially at the beginning of workouts. So adding moisture to the electrodes of the strap becomes even more important to ensure the best connectivity and highest level of accuracy during training.
General Maintenance:
Heart rate monitor straps need to be free of non-conductive residues to sense the electrical activity of our heart and send that info from the strap to the transmitter. If the electrode area of the strap and the connection ports that the transmitter snaps onto get too dirty, then they need to be cleaned. After each use, rinse the belt with water and let it dry in the shade to prevent sweat residue buildup. Once every couple of weeks, do a deeper clean of the strap.
See the full details in the question about cleaning at the FAQ link below.
https://trainwithmorpheus.com/topic/m7-heart-rate-monitor/
When you are not wearing the M7, always completely unsnap the transmitter from the chest strap to save battery life and prevent it from power cycling on and off. It will turn on automatically when you snap it back into the strap after you are wearing the strap. Store the sensor in a way that it is not in contact with anything conductive. If it is touching anything conductive it will power cycle on and off repeatedly.
Normal wear and tear:
The M7 strap is made from nylon, spandex, and rubber, which eventually wear out over time.
Routine wear-and-tear isn’t always visible, since the electrodes are covered by rubber strips and may lose effectiveness below the surface.
If the electrodes are not working properly, they cannot accurately measure your heart’s electrical signal.
If you are following the steps above to get accurate and consistent readings, and then the readings become inaccurate and/or you start to experience disconnections, it may be time for a new strap.