Man I felt as weak as a kitten for the first few months PT (post Tx). At first I couldn't even lift the water bottle up and on the water cooler. Calories and hydration and tons of it will help. Even driving at night for the first time PT was weird, almost scary. I bought a Camelbak and got up enough nerve to get back on my bike at 3 months PT. I felt OK but the DM sucked and made it very difficult to ride and sip water constantly. This was December. Then came my Tax Season so the next time I gave riding a try was late April. By now I was 8 months PT. I discarded that Camelbak and actually enjoyed myself. Even though the DM was still bad I found that if I didn't try and talk to other riders, chewed Biotene gum and carried an extra water bottle I was fine. Before long I was back to riding just as I was pre Tx. In fact with my weight loss for a year or so I was a better rider than pre Tx. Now I spend 5 days at the Y doing Spin and resistant equipment and 1 to 2 days on the bike. I am in as good or even better shape today than I was pre cancer. Just wish I could stop the age thing! lol