My spo2 level drops 5-10 times at night. Sometimes down to 78. Should I worry ? Avarage is allways above 90

Just as a reference for others, iterested in this topic, I answered the question already on the forum of the standard Instinct (although it has no PulsOx sensor, and I have no personal experience with Instinct Solar's PulseOx):

Generally, (excluding the malfunction of the sensor) when the SpO₂ drops during the night, it may mean you suffer a sleep apnoea. Another possibility is a peripheral vasoconstriction - that can happen again as a consequence of the sleep apnoea, but also for example due to the cold. You should consider visiting a specialist for sleep disorders, since sleep apnoea may lead to serious consequences on your health.

On the other hand, the biggest drop in SpO₂ is at the end of the deep sleep, and it is only brief, so it indeed looks like it could be caused by the low breathing pattern, or a brief apnoea, but generally the saturation levels are not critical the whole night (the wrist PulseOx underreports the SpO₂ value, so the true saturation is likely a bit higher). Consulting a specialist would be still recommandable, though, I think, especialy if such low levels appear regularly.

No, you should not be worried about it. Your watch is not a medical device and is not guaranteed to provide accurate readings. Just look at how many gaps there are in the graph.

If you are feeling OK, just live your life. If you think there is something wrong with see a doctor.

Thanks

My spo2 levels are around that range while using my CPAP machine for sleep apnea. When I'm not using it, the average drops to 82%. I would seek evaluation for possible sleep apnea. I used my Garmin D2 to track my levels and requested a test with hospital grade equipment, they results are the same as the sensor on my watch. Supplemental oxygen was added to my cpap to raise those levels. Although the watch sensor is not a 'medical device', it has literally been a life saver for me. I'm 36 and other than having sleep apnea, I'm a very healthy individual, but oxygen deprivation can have serious consequences on your body.