96. When to Recite Shema

17:1 The time to say Shema in the morning begins at the same time when one may first put on his tefillin, namely when it is light enough to recognize an acquaintance from about six feet away (refer back to 10:2). The time for Shema lasts through the first quarter of the daylight hours, whether they are long or short. “Daylight hours” means from dawn until the stars come out, though there are other opinions. The optimum time to read is “k’vasikin,” like those who love the mitzvah so much that they would arrange to recite Shema ending with the appearance of the sun, followed immediately by reciting Shemoneh Esrei. If one can do this, it’s meritorious; if not, he should at least be careful not to miss the end of the time for Shema, which can be before 7:00 AM sometimes. However, if one happened to miss the time for saying Shema, it should still be recited, with its blessings, until the end of one-third of the day. After that, one should still recite Shema but he may no longer recite the brachos before and after it. This is the case the entire day; some authorities do permit saying the blessings even later. (Biur Halacha 58, s.v. “Kora’ah b’lo birchoseha,” permits reciting the brachos until noon so long as one was prevented from saying Shema sooner by circumstances beyond his control.)

17:2 Shema may be recited sitting or standing. If one was already seated, he may not act stringently (like Beis Shammai) by standing to recite Shema. (At Maariv, one who is standing may not sit for Shema – see Mishnah Brurah 63:7.) One may not recite Shema lying down. If he is already lying down, he should turn on his side to say Shema. (This is if one has already gotten undressed; if he is still dressed, he must get up – MB 63:3.) If one is a little sick (or very fat – OC 63:1) so that it is difficult to lie on his side, he must at the very least lean a little to the side.