Question: Should a person who only went to sleep after dawn say a berachah after netilat yadayim when he wakes up?
Answer: Rabbi Asher Anshel Katz, zt”l, rav of Kahal Serdehely in Boro Park, Brooklyn, discusses this matter (U’l’Asher Amar, siman 2). He initially writes that a person should wash netilat yadayim in the morning considering that the Mechaber (Orach Chayim 4:13) leaves the question open and the Rema says he should (without a berachah).
Rabbi Katz argues, however, that this ruling only applies if he washed his hands before he went to sleep in the morning since we are unsure why we wash netilat yadayim altogether. The Rashba says we do so because we are a bria chadasha (a newly created being) when we arise after a night’s sleep (and our sages made no distinction, lo plug, between people who sleep at night and those who don’t). The Rosh, though, argues that we wash netilat yadayim because “yadayim askaniyot heim” – a person’s hands might have touched an uncovered part of his body; this concern, though, only applies to someone who slept.
Rabbi Katz notes that according to the Magen Avraham (sk 12) and Rashba, it is doubtful if a person should say a berachah because it’s possible that only when a person slept at night and awoke as a bria chadasha does he have to wash netilat yadayim and say a berachah.
If the person went to sleep in the morning before he washed his hands, though, he should wash netilat yadayim and say a berachah, argues Rav Katz, because both reasons now apply. Since he slept, he is a bria chadasha and probably touched an uncovered part of his body because yadayim askaniyot heim.
The reason the Magen Avraham says a person should not say a berachah on netilat yadayim if he washed in the morning before he went to sleep is because, says Rav Katz, he already washed his hands once. He is a bria chadasha once, not twice. Therefore, he already fulfilled his requirement of netilat yadayim insofar as the reason of bria chadasha is concerned.
Rav Katz also notes the position of the Bach (cited by Magen Avraham) who rules that a person should say the berachah on netilat yadayim even if he stayed awake the entire night. The Magen Avraham disagrees with the Bach and dismisses his proofs, but he might agree in our case where the person did not wash his hands in the morning before going to sleep.
Rabbi Katz cites Derech Chaim (Hilchot Netilat Yadayim, sk9), which states that a person shouldn’t say the berachah on netilat yadayim if he went to sleep before it got dark and awoke when it was night. For ruach ra’ah alone, the Sages did not require a blessing and the person is not created a bria chadasha twice in one day. Our case is different, though, since the person went to sleep after dawn and awoke later as a bria chadasha.
He also cites the Aruch HaShulchan (Orach Chayim 4:12) who rules that the person should say the berachah on netilat yadayim. Rabbi Katz finds this ruling surprising since we usually follow the rulings of the Rema.
The Mishnah Berurah (Orach Chayim 4:30) writes that in such a case, a person should go to the bathroom to take care of his needs and then recite the blessings of al netilat yadayim and asher yatzar. He notes that people who stay up all night on Shavuos and then wish to pray Shacharis should follow this procedure.