It's no less dangerous. There is only so much strain that the human body can take. Even in a state of deep sleep, humans still need sustenance. If they're left motionless for too long, their muscles will atrophy.

And for those who are sick or otherwise compromised to begin with... their bodies can't receive the treatment they need, but their disease doesn't stop just because they're sleeping.

They grow weaker and weaker, until...