I learned from someone's sharing about exercising. I used to work out regularly and I also felt energetic and refreshing after working out. Like jogging , hiking , doing push-up and lifting dumbbell and so on. But in recent two years , I got lazy and seldom do that again. Just stayed a habit of jogging sometimes. Recently I tried to do push-ups and I found I was having a hard time finishing it even within 1 set of 10. So just like what you've said above , we have to stay exercising regularly to keep our muscles stronger and more fit . I decide to resume my exercise routine every day , and start from simple one to finish easily.