Shalom Rav, I have a congregant who is taking on a night job where he will work all night, arrive home after sunrise and then go to bed. Since his now kavua “bedtime” is in the morning he asked if he could still say the bedtime Shema. The Biur Halakha on Shulchan Arukh OC 239:1 seems to clearly say one should not, at least not the berakhah, and the Arukh HaShulchan mentions that the point of the Shema al HaMitah is to protect from demons, which would only be a night problem. Does the fact that his bedtime is officially during the day matter, or is the bedtime Shema tied to the time of day, not an individual’s bedtime? If no berakhah is allowed should I just suggest he recite some or all of the paragraphs of the Shema? Thank you and Shabbat Shalom!
This is not a question about the second Shema of the day which is a chiyuv de’orayta and has to be before Alot HaShachar. It is specifically a question keriat Shema al HaMitah.
You are correct that the Mishnah Beruria rules in the Biur Halakha that it is not said if one goes to sleep during that day, and that is the consensus among the poskim. (See Yechaveh Da’at 4:21 “אנ טרם”). The reason is generally given not because of mezikin, but because Chazal were only metaken this at the normal time that people went to sleep. I would say that we see two elements of what this is about. One, saying Shema/Torah as a way of going to sleep in the context of learning. One would be learning the peshat of the pesukim and also one’s mind when dreaming is oriented that way and not towards sexual matters leading to zera levatalah (Arukh HaShulchan). Two, it is a prayer that God watch over us at night and allow us to see the next morning. This is clearly indicated in the berakhah. The mezikim is very secondary, although it is present in the passage said after Shema. Based on these reasons, one could definitely say that the second reason is connected to the fear of night, and not just of sleep, and that would only say it if one goes to sleep at night. Even the first reason, Torah as framing one’s sleep, connects to the context of the pesukim of בשכבך, which are also – according to halakha – specifically about the general night. Although one could in theory debate either of these points, this is the the consensus of the poskim.
If he goes to sleep between Alot HaShachar and HaNeitz HaChamah, there are some positions to rely on that he can say the berakhah, but I would not. I think he should just say the regular keriat Shema al hamitah without the berakhah, regardless of when one goes to sleep. One could argue not to bother saying it at all, but I think from a subjective experiential perspective the values I mentioned above are still relevant.