I've been reading Oz vehadar (R' Pessach Eliahu Falk) and one doubt came up:
If a woman should stay tznuah even in private (like rules on what pajamas not to wear, and about the length of the nightgowns, etc.), how come there are plenty of women-only gyms, and beaches in which women can be on bathing suits - of course, assured no men are around - and so on? Should I quit all these?
When discussing the question of covering one's hair at a women's only gym, dinonline writes, "From the various rabbonim that I have consulted on this matter, it seems controversial, just like the two sides of your question. Some said that it is not permitted and others said that it is. However everyone agreed that it isn’t the preferred thing to do, and if possible she should be dressed b’tznius" http://dinonline.org/2017/01/24/covering-hair-in-all-womens-gym/ There is certainly a grey area which would be addressed differently depending on your particular circumstances. There's no one size fits all halacha in this regard.
comments above are very interesting
to answer see Mishna Brerura 2.1
regarding Tznius for men (in my understanding woman should not be more lenient regarding this then men) Tznius not for sexual reasons just out of respect/fear of G-d (he is everywhere, so should should at respect him as you would a king in that place if possible, being in private or in the dark does not change anything in this regard)
...
והאדם צריך להתנהג בצניעות ובושה לפני הקב"ה ואפילו כשהוא לילה ובחדרי חדרים הלא מלא כל הארץ כבודו וכחשיכה וכאורה לפניו יתברך ...
וכן צריך ליזהר תמיד מחמת טעם זה שלא במקום הכרח מלגלות מבשרו ואפילו מעט כל מה שדרכו להיות מכוסה בבגדים לעולם אבל רשאי לגלות ידו עד קוב"דו וצוארו עד החזה ע"כ ...
אם לא שאי אפשר בענין אחר וכן בבית המרחץ שדרכן של בני אדם לילך שם ערומים וא"א בענין אחר אין בזה משום פריצות וכן כשרוחץ בנהר הדין כן רק יזהר לפשוט וללבוש סמוך לנהר כל מה שאפשר בכדי שלא ילך בגילוי הגוף שלא לצורך...
it seems that it you should try to get dressed as near the beach as possible so as not to walk with open body without necessity
"Should I quit all these?" so it seems that if it is something you need (i guess health is something you need) then you should not quite if there is no other way (it seems that "no other way" does not include unusual measures just other ways that are customable) of doing it
if it is not something you need or there are other ways of achieving it (maybe going to gym with cloths, see NEW YORK POST) then you should try quit or do it the other way.
The source in Halacha regarding tznius/hair covering in private areas begins From the passage in Ketubot (72b),
It would seem that a woman is only required to cover her head when she is out on the street. In her house or courtyard, she may walk about with her head uncovered. Although some have attempted to explain the gemara differently (Bach, Even Ha-Ezer 115), this is the plain understanding of the gemara and the Rishonim.
There is, however, a Talmudic source that seems to praise a woman who is meticulous about covering her hair even in the privacy of her own home:
Furthermore, it is told of R. Yishmael ben Kimchit [who was a High Priest] that he went out and talked with a certain [non-Jewish] lord in the street, and spittle from his mouth squirted on his garments [rendering him impure], whereupon Yosef his brother entered and ministered in his stead, so that their mother saw two High Priests on one day. The Sages said to her: What have you done to merit such [glory]? She said: Throughout the days of my life, the beams of my house have not seen the plaits of my hair. They said to her: There were many who did likewise and yet did not succeed. (Yoma 47a)
The closing words of the Sages imply that they questioned the explanation provided by Kimchit. Nevertheless, there are those who inferred from here that it is good for a woman to be meticulous about covering her hair even at home, and even when not in the presence of other men. To this we can add the words of the Zohar, which is very stringent about a woman covering her hair. Just as many learned from the Zohar to be stringent about covering the entire head, they learned from it to be stringent about covering the head even at home and in one's courtyard.
It should be noted that the accepted practice for generations has been to be stringent about this. So ruled the Chatam Sofer: "The rule that emerges: All hair anywhere on the head or forehead of a married woman, even in her room, is a sexual incitement" (Responsa Chatam Sofer I:36).
Although it would appear that in the time of the gemara, women were not meticulous about covering their heads in their courtyards, but only on the street, women have been stringent about this for many generations, until our very day. The reason seems to be that since a woman is meticulous about covering her hair outside, removing that cover in her house in the presence of strangers is deemed an overly intimate gesture. Of course, in the absence of strangers, the great majority of Jewish women do not conduct themselves as did Kimchit, and do not cover their heads in the privacy of their own homes.
It should further be noted that the propriety of a wig is subject to major controversy. The mishna in Shabbat 64b speaks explicitly of a woman who goes out into the public domain wearing a wig. The Shiltei Gibborim (no. 375) demonstrates that the gemara refers to a married woman who uses the wig to cover her head, and he writes that an allowance should be granted even to a wig made from the hair of that very woman. The Peri Megadim (Orach Chayyim 75, Eshel Avraham no. 5) and the Iggerot Moshe (Even Ha-Ezer II:12) rule similarly.
