Related for Berakhot 48:19

One that was standing in the field naked or that was doing his work naked should cover himself with straw and with stubble or anything [else for that matter] and may read [the Shema]. Even though they (i.e. the Rabbis) said that it is not praiseworthy for a person to be sitting naked, because the Holy One Blessed Be He did not create man naked as it says, “I clothed him in a cloud and [made] mist his shroud.” (Job 38:9) “Clothed him in a cloud” that [refers to] the sack of the fetus, “and [made] mist his shroud” that [refers to] the placenta. [If] there was a wrap of cloth or of skin wrapped around his loins he may read [the Shema]. Either way he should not pray [Shmoneh Esreh] until he covers his heart.