Cold has been the only factor that wakes me. In the previous life as a ground dweller I would always wake up relatively early in the AM. Never took naps. On couple occasions I've overslept in the hammock. Tired, comfortable, dark colored tarp & tree shade resulted in missing sunrise by a few hours. I string up the hammock occasionally for a late afternoon nap. Nice hanging among the trees on a warm summer afternoon to totally waste away a moment or two.