How do some parents look like they have so much energy even if they many kids?

For me it's the same way, however, I do get out and have "me" time. I eat pretty good, and I work out. At my age (33) my metabolism was slowing down. I felt like when I got home all I wanted was the bed, but had to do a few chores, homework, spend quality time with my son, dinner, get ready for the next day... Hopefully this helps, but, I make time for me, I believe that is very important, Even if it's just going to a spa, or shopping, or just laying around in the house doing nothing..Maybe a girls nite out.... Also, I believe eating properly, having a balanced diet also helps... In a sense, to me, it's similar to working...If I'm off work for a few days, when I go back I'm refreshed and ready to take on the day...I've had that time to clear my head, relax, catch up on things that were behind. It's the same with our bodies and our mental state...I use to be so routine that I was trapped and always tired adn feeling depressed like here I go again..the same thing over and over..Good luck to you