short breath (bodybuilding, sex)

hello. i am a 23 year old male who has good general health. i have some questions that i think might be related. i really need some input on this subject.

first question how does intense bodybuilding affect the performance of the heart? i heard that it might after a while alter the shape of a heart, particularly the thickness of the walls and that in general it reduces a persons cardiovascular performance.

second question have noticed on a consistent basis that for two days after performing intercourse my cardio performance is especially weak. after a fast walk i could be panting and feeling tired and it takes a good minute, minute and a half for the heart rate to get down. in contrast after four days from intersourse the shortness of breath is nonexistent. when on a bike the heart rate after four days is usually 20 bpm below when on that of two days . is this normal?

third question occasionally i have intercourse the same day as strength training. is that okay? what effect does it have on my cardio performance.

thanks for you time. appreciate your help