[DwnVoteHoneyPot]

I live in a rural area. My old fashioned doctor said to test oxygen levels, all you need to do is pinch your index finger nail down until it goes white. Then when you let go, if it goes back to pink right away, you're good. If it takes more than a few seconds, you're not good.

[qgin]

That's the capillary refill test which tests circulation and perfusion. Doesn't really tell you anything about oxygen levels.

[monkeyelite]

Of course. Billions of people have lived without this. You also don’t need a computer on your wrist.

But many people are willing to pay get more health information, especially wealthier demographics who have interest in health and appearances of health.