Red Sensor Light was ON

[MattJ71]

I just noticed that my red sensor light was on for a while today.  Looks like the SPO2 sensor might be activated soon.

[SunsetRunner]

Don't hold your breath!

[Cantryboy]

@SunsetRunner Literally 

[N8teGee]

Both my Ionic and Versa have been doing this for a long time. The red LED is activated when you go to sleep and it turns off just after you wake up.

I heard someone post that it's used for more accurate sleep stages, whether this is true or not I don't know. 

[MarreFitbit]

Hey guys @MattJ71, @Cantryboy, and @SunsetRunner, thanks for stopping by!  In regards to the red light, as my friend @N8teGee mentioned, the optical heart rate turns red during the tracking of sleep and changes to green shortly after the customer is awake. This is an expected behavior! 

Hope this clarifies your inquiry, let me know if you need further assistance!  

[SunsetRunner]

So I just had a long chat with support and it said that the ionic specialists could not yet tell us what the red light sensor does or when the red light sensor's mysterious/unknown function will be enabled.

Can someone please clarify what the red light sensor does and when it will be enabled? 

[SunsetRunner]

Kate, Customer Support is the LAST word around here.

[MarreFitbit]

Hey @SunsetRunner, thanks for jumping in here! As I mentioned above, the optical heart rate turns red during the tracking of sleep and changes to green shortly after you are awake. 

[SunsetRunner]

HI Marre - thanks.  So when I am awake there is no difference in the accuracy of the fitness monitoring between the Ionic and the Alta HR.  It is the same technology and even once the red light sensor is enabled on the IONIC, it will ONLY turn on at night and never during the day.  Is that correct?

[MarreFitbit]

You're welcome @SunsetRunner! If you're talking about the red light during the day, so you're right. Only the green lights will be working to detect your heart rate throughout the day.  

I'd recommend taking a look at the article: What should I know about my heart rate data?

Let me know if you need further assistance! 

[MattJ71]

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@MarreFitbit wrote:

Hey guys @MattJ71, @Cantryboy, and @SunsetRunner, thanks for stopping by!  In regards to the red light, as my friend @N8teGee mentioned, the optical heart rate turns red during the tracking of sleep and changes to green shortly after the customer is awake. This is an expected behavior! 

Hope this clarifies your inquiry, let me know if you need further assistance!  

---

Well, the RED light was on during the day today when I was fully awake.  I just happened to check it and it was flashing GREEN and RED.

I've had my Ionic since launch day and have NEVER noticed it before.

[MarreFitbit]

Thanks for reporting this @MattJ71! I'd recommend restarting your Ionic as this should only happen when you're asleep. Here are the steps for the restart:

1. Press and hold the back (left) and bottom buttons until you see the Fitbit logo on the screen. This should take less than 10 seconds.
2. Let go of the buttons.
3. If your Fitbit Ionic doesn't work normally, use the instructions in How do I turn off my Fitbit device? to turn your watch off and on again.

 Hope this helps, I'll be around if you need anything else! 

[SunsetRunner]

Morning all. 

@MattJ71 - just noticed my Ionic (whilst taking it off to charge) had both RED and GREEN lights flashing at the same time - first time I've ever noticed this, and I too have an Ionic since launch. 

Bizarre. Just thought I'd share. Is yours still doing this?

[N8teGee]

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@SunsetRunner wrote:

Morning all. 

@MattJ71 - just noticed my Ionic (whilst taking it off to charge) had both RED and GREEN lights flashing at the same time - first time I've ever noticed this, and I too have an Ionic since launch. 

Bizarre. Just thought I'd share. Is yours still doing this?

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My Ionic and Versa do it every night, they revert to green only soon after I get up. 

[MattJ71]

After weeks, I can confirm that the RED and GREEN flash when I'm sleeping.  Shortly after I get up (after a few minutes) only the GREEN flashes.  Fitbit is definitely activating the SPO2 sensor at night... perhaps testing...

[AD1971]

It's been months since the last post in this thread. Does anyone have a solid answer? Fitbit staff, where are you? I know the red/amber LED light is normal when sleeping...I get that. My question is WHY? What's it doing when it's red/amber? Please make a statement on this.

[Skyrider]

It's a method that can be found in most hospitals and has been used in the medical industry for tests like pulse oximetry, which measures oxygen levels in the body. The body is a poor absorber of red light allowing the light to pass much deeper into the body and a larger volume of tissues to help provide more insightful data and could lead to improved accuracy with biometric data like heart rate.

Using a combination of red and IR wavelengths can be used to assess SpO2 (blood oxygenation) when worn at the finger, forehead, or ear, and to assess muscle oxygenation when worn at the wrist, arm, or leg. Moreover, using IR light can help with reducing sunlight noise (the sun generates a much higher percentage of green light than IR light), helping folks sleep at night (no green light glow in bed), and with helping to remove motion noise from signals

Needless to say, it's used to get the blood oxygen (aka SpO2). Though, as most (and me mostly noticed) the combination of red and green lights are only mostly triggered/enabled while asleep, or when waking up. 

[AD1971]

Yes @Skyrider but what is Fitbit doing with it? There is no such feature. 

[AlexMatthews]

Mine just turned on and won't turn off? It's 11:41 am. Also my sleep tracker hasn't worked these last few days? And the battery dies after just 1 day? Any thoughts?

[SeattleRos]

Exactly the same here