Why exactly does the ru’aĥ ra’ah linger specifically on one’s hands? Is it the mere state of sleep, when one’s consciousness abandons her and she is left without the ability to function? If so, even one who sleeps during the day would be required to wash her hands three times upon awakening. Or does the night, when the whole world ceases its activities, cause ru’aĥ ra’ah, in which case even one who was awake all night must wash her hands three times?
In practice, when both factors converge and one sleeps a regular slumber (at least half an hour), the ru’aĥ ra’ah rests upon her in full force. In such a case, immediately upon rising one must hurry to wash her hands three times and refrain from touching her bodily orifices or food prior before washing.
If one slept a regular slumber during the day, it is proper to be stringent and wash her hands three times alternately, but it is unnecessary for her to rush to do so since the ru’aĥ ra’ah is not in full force. Also, there is no prohibition on touching bodily orifices before washing.
If one remained awake all night, it is best for her to wash netilat yadayim three times after dawn, as there are those who maintain that the night itself, or its end, causes ru’aĥ ra’ah to descend upon the hands. Likewise, it is proper for one who arose in the middle of the night and already washed her hands three times when she woke up to wash her hands again at dawn, (Peninei Halakha: Prayer, ch. 8 nn. 4-5).