Isn't it lovely, all alone? Heart made of glass, my mind of stone
Tear me to pieces, skin to bone
Hello, welcome home

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)

60 minutes or more of a combinationof aerobic and muscle-strengtheningexercises physical activity recommendation.adults