Cardiovascular activity primarily trains the body to become more efficient with calories, leading to a slower metabolism and reduced calorie burn over time.

“what it also does is it tells your body to get better at cardio which requires not much strength in fact less muscle actually makes you better at this type of cardio activity because you become more efficient with calories so your body actually learns to burn less calories and over time your metabolism slows down and you actually burn less calories even while you do that particular activity so the adaptation from cardio actually teaches your body to be more efficient with calories aka burn less calories all the time and so you slow your metabolism down”