If you are reading this post, it is definitely because your Garmin GPS Watch has been flashing red or green from the back, and you are either terrified or curious about what it might mean.
First and foremost, it is important to mention that the red or green blinking light on your Garmin watch is not a bad thing. In fact, it is quite the opposite.
If your Garmin Watch is flashing red, it means that it is equipped with a Pulse Oximeter optical sensor that uses LED lights to measure the amount of oxygen in your blood.
Whereas, the Green light on your Garmin Watch is used by the optical heart rate sensor that also uses LEDs to take your heart rate readings from the blood flow.
Here’s more about the red and green flashing Garmin Watch light and how to disable it if you do not like what it does.
Table of Contents
How does Pulse Oximeter Work on Garmin Watch?
Pulse Oximeter, also known as a SpO2 sensor, uses a combination of red and infrared lights to determine how much oxygen is being carried by the red blood cells from the heart to the various parts of the body.
Oxygenated and deoxygenated blood differs in their absorption of light. Oxygenated blood absorbs more infrared light, whereas deoxygenated blood absorbs more red light. This difference is what the sensor uses to calculate the amount of oxygen in your blood.
As you breathe, your lungs fill your blood with oxygen, and your heart then pumps it to all parts of your body. Hemoglobin is the protein is responsible for absorbing oxygen in the blood.
In normal cases, this value should be more than 95%. If the value falls below 90%, you have every reason to visit your doctor.
- Blood oxygen saturation level is particularly helpful for climbers and divers, as it can give them an indication of how their bodies are adjusting to the altitudes or depths.
- It helps the athletes to adjust their performance as the oxygen level drops if they overdo an activity.
- It also feeds into the Sleep tracking data of most watches and can help detect Sleep Apnea.
Keep in mind that the red and infrared light from the SpO2 sensor of Garmin watches doesn’t harm you in any way.
How accurate is Garmin Pulse Oximeter?
Optical Sensors are not as accurate as clinical-grade fingertip sensors. However, they are good enough to give you a general idea about your blood oxygen saturation.
Generally speaking, Garmin’s Pulse oximeter sensor is as good as you find in the Apple and Fitbit watches. However, just like its competitors, Garmin advises its users to not rely on the data from the SpO2 sensor as a replacement for a medical-grade device.
Pulse oximeter readings can be affected by various factors such as skin color, wrist movement, physical exertion, and so on. So, your SpO2 data might not be entirely accurate. We would recommend you keep close tabs on the trends rather than fretting about individual readings.
How does the optical Heart Rate Sensor Work on Garmin Watch?
Garmin watch come equipped with a green light-emitting optical heart rate sensor that uses what is called Photoplethysmography (PPG) to take your heart rate readings.
PPG is a method of measuring blood volume change in the microvascular tissue using a light source and photosensor. The light sensor emits green light, which is then absorbed by your blood via Hemoglobin.
The more green light reflected by the photosensor back to the watch, the lower your heart rate. Why is that so? During relaxation (diastole), the density of Hemoglobin drops significantly, and so drops the blood absorption. This results in more green light reflecting back to the photodiode detector in the watch.
How do I turn off the red light in Garmin? (Venu, Forerunner, Fenix)
To turn off the red light on Garmin Watch, you will have to disable the Pulse Oximeter Sensor. Here is how you can do that on different Garmin Watches.
| Product Name | How do I turn off the red light in Garmin? |
| Garmin Vivoactive 4/4S | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Select Pulse Ox >>Select Tracking Mode >> Tap Off to Turn off the Pulse Oximeter Sensor. |
| Garmin Venu 2 | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Select Pulse Ox >>Select Tracking Mode >> Select On Demand to Turn off the Pulse Oximeter Sensor. |
| Garmin Venu | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Select Pulse Ox >>Select Tracking Mode >> Tap Off to Turn off the Pulse Oximeter Sensor. |
| Garmin Venu 2 Plus | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Select Pulse Ox >>Select Tracking Mode >> Select On Demand to Turn off the Pulse Oximeter Sensor. |
| Garmin Venu Sq | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Select Pulse Ox >>Select Tracking Mode >> Tap Off to Turn off the Pulse Oximeter Sensor. |
| Garmin Fenix 7 | Hold Down the Menu >> Select Sensors & Accessories >> Select Pulse Oximeter >> Select Pulse Ox Mode >> Tap Manual Check to Turn off the Pulse Oximeter Sensor |
| Garmin Fenix 6/6S/6X Pro | Hold Down the Menu >> Select Options >> Select Pulse Ox Mode >> Tap off to Turn off the Pulse Oximeter Sensor |
| Garmin Forerunner 245/ 245 music | Open the Menu >> select Pulse Oximeter widget >> Hold the Up button >> Select Sleep Pulse Ox >>Tap off to Turn off the |
| Garmin Forerunner 255/255S/ 255 music/ 255S music | Open the Menu >> select Pulse Oximeter widget >> Hold the Up button >> Select Pulse Ox Options >>Tap off to Turn off the |
| Garmin Forerunner 945/945 LTE | Open the Menu >> select Pulse Oximeter widget >>Select Options >> Select Pulse Ox Mode >>Tap off to Turn off the |
| Garmin Forerunner 955 | Open the Menu >> select Pulse Oximeter widget >>Select Options >> Select Pulse Ox Mode >>Tap off to Turn off the |
How do I turn off the green light in Garmin?
To turn off the green light on the Garmin watch, you will have to disable the heart rate sensor. Here is how you can do that on different Garmin Watches.
| Product Name | How do I turn off the Greenlight in Garmin? |
| Garmin Vivoactive 4/4S | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Venu 2 | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Venu | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Venu 2 Plus | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Venu Sq | Hold Down the Side Button >> Tap on the Settings >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Fenix 7 | Hold the Down button and open the Menu >> Select Sensors & Accessories >> Select Wrist Heart Rate >> Tap on the Status to turn Off HRs. |
| Garmin Fenix 6/6S/6X Pro | Hold the Down button and open the Menu >> Select Heart Rate Options >> Tap on the Status >> Select Off to turn Off HRs. |
| Garmin Forerunner 245/ 245 music | Open the Menu By Holding the Up Button>> select Wrist Heart Rate >> select Status >>Tap off to Turn off the HRs. |
| Garmin Forerunner 645 | Open the Menu By Holding the Up Button>> select Settings >> Select Wrist Heart Rate >> select Status >>Tap off to Turn off the HRs. |
| Garmin Forerunner 255/255S/ 255 music/ 255S music | Open the Menu By Holding the Up Button>> select Settings >> Select Wrist Heart Rate >> select Status >>Tap off to Turn off the HRs. |
| Garmin Forerunner 945/945 LTE | Open the Menu By Holding the Up Button>> select Settings >> Select Wrist Heart Rate >> select Status >>Tap off to Turn off the HRs. |
| Garmin Forerunner 955 | Open the Menu By Holding the Up Button>> select Settings >> Select Wrist Heart Rate >> select Status >>Tap off to Turn off the HRs. |
Wrapping Up:
If your Garmin watch is blinking red and green on the underside, there is no need to worry. It is completely normal and just indicates that the watch is taking your Pulse Oximeter and Heart Rate readings.
However, you might want to turn these lights off during sleep to avoid any disturbance or to save the battery. We have shared with you, how you can turn on and off both the red and green lights.