I work in EMS on an ambulance (night shift) so my job goes from sitting at a post and chatting with my partner, to taking off on a call for a chest pain, carrying a 250lb man down 6 flights of stairs, caring for him, driving (or riding in the back) lots of walking through ERs, lots of lifting, bending, climbing, squeezing, pulling, etc. We never know what the next call is going to require of our bodies. Basically my shift swings from sedentary to full bore physical labor and back again. It's very hard on the body. But I've found that my 7 mile round trip commute gives me a good, steady workout without exhausting myself before or after a 12 hour shift. On my days off, I usually do a 10-20 mile ride just for fun. I maintain a balanced diet with very little processed foods, lots of water and fresh squeezed juice. I pack a lunch for work and eat small amounts throughout the shift. Btw, I'm 24 yrs old, female, 110 lbs on average and about 4% body fat. I can also dead lift 100 lbs. I'm trying out for the fire department in '08.