Hypoxia

"HOWEVER, you will see that people will tend to GO bradycardic (and eventual heart failure) with "sustained" SpO2s around 84-88% by starving heart muscle. Decline is even more rapid below 84% SpO2, as that drops your pO2 at or near the venous threshold of 40 mmHg. Now, remember, this is "opinion" based on experience. I can't think of any reference material that will give you a specific window of Oxygen Saturation that equates cell death (as mitochondria vary from individual to individual). "