<span>This would be renal failure. The person's kidneys would stop functioning, either because of a disease directly affecting the kidneys or through some other means that would have an indirect effect on the operations of the kidneys, leading to a sudden failure.</span>
A mammals need for oxygen effects their heart rate because there could be some cases where they're in lack of oxygen causing them to be literally ' out of breath ' . Like climbing a mountain. The higher you go the less oxygen.
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