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Pulse Ox low of 74% during sleep. How accurate is the reading and is it cause for further investigation? Headache, fatigue, CFS/M.E/CPTSD

4859091
over 4 years ago

Hello,
I just got my Venu a couple of days ago. I've only recorded 1 night of sleep so far, so I am probably getting ahead of myself, but I'm curious about the results as I find them very interesting!

During the day my pulse 0x is good, showing 98-99% generally. Overnight it fluctuates a great deal more with an average of 90% and the lowest value being at 74% and a lot of readings in the 80s. My average heart rate is at least 10 points higher overnight than my resting heart rate during the day. Respiration varies from 5 to 18 breathes per minute with an average of 12bpm. Stress levels show as fairly high overnight (I was indeed very stressed out) and my body battery drained by 9 points overnight, showing -17 today. It shows only an hour and a half of deep sleep, with 5.5 hours of light and just over an hour of REM.

This actually seems fairly accurate for my circumstances. I suffer from Chronic Fatigue Syndrome/M.E (for nearly 20 years now), a key symptom of which (besides the obvious of chronic fatigue and not being able to recharge your body battery/recover from exertion) is poor and unrefreshing sleep. I'm often pretty restless in the night, struggle to get off to sleep, wake up a lot, toss and turn or have boughts of insomnia. I feel I get very little deep sleep (and this forms part of the theory as to why people with CFS don't feel rested after sleep). Every morning I wake up with a bad headache, feeling heavy, fatigued and brain fogged with a sense of malaise.

I know my illness is caused by Complex PTSD and I know that my body is stuck in a trauma state, one of the symptoms being shallow breathing. I have noticed when I'm drifting in and out of sleep that my breathing becomes very shallow. I've had a partner comment on how shallow my breathing is during sleep in the past. They said they've often had to check that I'm actually still alive because I look dead!

It's been very interesting to see the results of the pulse ox and sleep analysis seemingly accurately reflect my experience. Again, I know it's waaaay too soon and I need to track my results for several weeks/months to see if this is consistent and I know it's not a medical device and cannot offer any kind of diagnosis. However, I'm interested by the low pulse ox readings during the night and wondering if this could correlate with my symptoms of headache and fatigue upon waking. I tend to feel at my worst upon waking. If these sorts of readings persist and it turns out to be my pattern, is it cause for further investigation with a doctor to check for things like sleep apnea etc? Or are the readings from the Venu just so inaccurate that they cannot offer any insights at all whatsoever? I know factors like how tight the watch is, how much you move, the position you sleep in etc can affect the readings.

Not expecting any medical advice or any advice with regards to my M.E (I'm engaged in a lot of therapies and lifestyle changes right now). I have a very deep understanding of my illness and there are all sorts of complex factors that can cause and influence my symptoms. Sleep apnea or other conditions that affect oxygen levels during sleep however is not a piece of the puzzle I have investigated yet, though I have previously been concerned with how shallow my breathing is. So I'm just wondering how accurate this device is and what insights it can provide someone like me in my situation? Or is it totally useless?

Thanks Slight smile

  • 0 over 4 years ago

    Regarding many of the symptoms you are describing, I would suggest to check if you suffer from sleep apnea. It is possible for sleep apnea patients to have a SO2 of 75% or lower. So the brain and body is always in an alarming status, which can explain the worsening of your other sytoms.

  • 0 over 4 years ago in reply to WidderStand

    Thanks, I appreciate your response. My readings were in the 80s last night, so I shall continue monitoring. I have realised today though, upon measuring my pulse with my fingers that the watch is not measuring my pulse accurately. It's about 15bpm off at rest. It's also inconsistent with my Samsung Galaxy S9+ HR monitor as well, although that is also not matching my actual HR (though is more accurate than the VENU it seems). The steps and flights of stairs climed are way off on the Venu as well, so I'm questioning the accuracy of the pulse ox readings now. Not sure what this £300 watch is supposed to do if all of the readings are inaccurate :(.Body battery dropped another 10 points overnight to a value of 5/100 (which could be accurate, I had a bad night. I am very tired, though not at my worst M.E wise.). I may still consider going to the doctor based on my symptoms though as sleep apnea is not something that has been previously investigated inspite of reporting these symptoms to various GPs for 2 decades.

  • 0 over 4 years ago in reply to 4859091

    There are some possible ideas: 

    1) Your Venu is "out of order", did you already reset it to factory defaults and re-configured it?

    2) Placement of the watch: switch it from left to right (or vice versa), same things happening? Is it too loose?

    3) Just take the values of the watch as a supportive idea to check sleep apnea, your symptoms are too indicative to not evaluate them. If you`re tested and it is not sleep apnea, then you know it by 100% and can go on.

  • 0 over 4 years ago in reply to 4859091

    I agree with . If I were you I'd be getting checked for sleep apnea.  Once diagnosed and treated it will change your life.  Whilst the absolute readings on your Venu are important (and we all want them to be accurate) but what is more important is that the device is telling you that you are Oxygen deprived during sleep.  This interrupts your sleep and your body is in a constant struggle to get the Oxygen it needs - this is what causes the fatigue.  Now I sleep with a CPAP machine and I'm a different person through the day and I sleep well at night.  Trust the watch and get it checked out.  Good luck.

  • 0 over 4 years ago in reply to md1709

    Thanks, yeah you're probably right. The only thing is my Venu has now been showing me daytime pulse ox readings of 89-93% (mostly 90%) whilst awake. Anything below 95% is supposed to be abnormal and indicates a problem. I am a chronically stressed out person who shallow chest-breathes rather than from the diaphragm (but apparently the vast majority of us are! And I do qigong, yoga and breathing exercises during the day, so I would expect to see it increase during those times). So, as I'm not short of breath or anything during the day, don't smoke, am otherwise healthy besides my M.E (no lung issues that I'm awae of), I'm calling into question the accuracy of the Venu again. I have noticed the pulse rate is up to 20 beats below my actual pulse when I've checked throughout the day too. I contacted Garmin about it a few days ago, asking if this margin of error is normal or whether I have a faulty watch. I haven't had a response yet.

  • 0 over 4 years ago

    I would suggest you get tested for sleep apnea. I used to wake up with headaches, sometimes wake up choking and my resting heart rate was always higher after I woke than sleeping. I did a overnight home sleep apnea test and was found to have minor sleep apnea. The test measured my SP02 hitting the low 70's during sleep. I now use a CPAP machine and no longer have morning headaches, my resting heart rate is now much lower and no longer wake up choking. Getting used to the CPAP machine took some time though. Now I sleep much better.

  • 0 over 4 years ago

    I would say the venu’s accuracy should not be totally relied on. It is not a medical device or clinically accurate (I’ve used medical pulse ox)  What would be interesting is perhaps using the sleeprecorder app and seeing if there is any correlation between the two. Pulse ox alone has limited diagnostic value in sleep apnea. Having said that, if you have any of the risk factors for sleep apnea I would definitely suggest contacting your gp and getting investigated. Your current mental and physical health issues sound like they are having a massive impact on your life and so even a mild sleep apnea could be adding to this and there maybe some changes that can be made to help. I tend to view the venu data in terms of a general trend to give me an idea of how well or not so well things are rather than how accurate each data field is as there are limitations to wrist based monitoring. Hope this helps. 

  • 0 over 4 years ago in reply to Fibrillate

    During the sleep I have around 94% in average. 

    But I always have a drop to 79%

    When I measure it during the day I have around 95% sometimeds a bit more. But when I use a certified medical device it is always higher. 

  • 0 over 4 years ago in reply to 4859091

    I wonder if applicable, your spouse observed your sleep with snoring AND gasping for air? I found that the Venu Pulse Ox monitoring overnight can tell you how often the O2 saturation levels dip below 90%, to 80% or even lower? This article provides some general info on how to tell or provide indications of a mild, moderate to severe sleep apnea:

    https://www.beverlyhillstmjheadachepain.com/sleep-apnea/pulse-oximeter-report/?fbclid=IwAR0RkNZr2B-tgdmBF8T_Axe_esGvtqi6PwQPuLTY6feoN0RmA4lHmyS6Nsc

    The Pulse Ox Timeline on the app/phone is rather coarse, not very useful. But you can log into Garmin Connect in your laptop, after synchronizing, the sleep report when viewed with Pulse Ox and Body Movement button selected, will show the SpO2 levels over the hours you sleep. There is a vertical marker that you can move along the "noisy" signal to see the exact SpO2 % desaturations at the exact time of the night. If you count total number of dipping below, say 90%, dividing by the hours of sleep, the result will give an idea if you likely have mild, moderate, severe, or unlikely sleep apnea, as suggested in the article above.

    As for accuracy, since i have another Oximeter, https://www.lookeetech.com/products/lookee-ring-sleep-monitor-w-vibrating-notification-for-sleep-apnea, I compare the SpO2 readings on both and found that the Venu is very close, not as refine, but relatively accurate. Note that both devices disclaim a medical device. However, among the reviewers of the Lookeetech Ring Sleep Monitor, someone claimed he/she a paramedic and found the SpO2 reading the same as those in the hospital If true, the Venu SpO2 readings are reasonably accurate, enough to tell if one suffers from mild, moderate or severe sleep apnea.

    Hope this helps!

  • 0 over 4 years ago

    I've VA4 which is basically the same device with a different type of display. And based on my experience, I'd say that you should take any reading with a grain of slat, probably a big grain sometimes Slight smile

    - PulseOX - is very tricky to measure on your wrist, you need to be very steady during measuring, to get it readings. Myself I tried many times do it manually with strap either tightly fit or somewhat loose, and compare my reading in real time with two other SpO2 sensors I have around, and in time when I had 99 on both of them my Vivoactive 4 managed to produce 80 or 90. Both these readings should make me concern and run to doctor of course. As any readings below 90 is a sign of the problem, but as I said I checked it with two other SpO2 meters which fit on finger and both confirmed that VA2 is basically useless which is sad, as cheap Honor Band 5 was measuring it perfectly. I believe it can vary from person to person but myself I kept it disabled.

    - I never enabled it during the day as it eats battery and while you're moving it wouldn't produce meaningful results but I tried it during two nights and it showed me results just like yours, though I can't say that I'm suffering from either headaches or other stuff. So I've just disabled it for sleep tracking too. I hope that Garmin would do something about it's algorithms to make it at least somewhat useful.

    - Sleep tracking, I've been Garmin user since 2017 and it was the reason I switched to other device as I loved activity tracking but sleep was more very inaccurate, and now when I decided to give another chance to Garmin and bought VA4 I have a feeling that sleep tracking is actually degraded even more and now it's just more of a guessing. It records me sleeping when I'm working and can first identify my sleep time one hour off the time I went to bed and during the day re-calculate it to even more weird time and add me 4 non-existing sleeping hours. So I'm using another cheap watch with SleepAsAndroid to track my sleep and set sleep hours correctly in Garmin Connect. At the same time I'm trying to resolve those issues with support. And advise everyone else who has problems with sleep tracking to do so as that what can help them to fix this issue and us to have a more reliable sleep tracking. Just try to reach them via chat, they have great support which I really love or drop them suggestions to www.garmin.com/.../

    - Activity tracking, here I'd say Garmin is way superior than any device I've tried so far and that's why I bought it in the first place and that's why I love my watch. Yes stairs never was accurate especially if you take a shower with your watches but steps, HR and other things seems to work well for me.

    In any case, just as others suggested, your symptoms sounds alarming even without any data from the watch and I'd consult with the doctor about it, sleep quality is important factor of feeling well so this alone should be a good reason to talk to a specialist.

    Good luck to you!