I used to swim and just watch the clock and count laps. Now the 30 minutes I plan to swim or at least be in the water, I frame in a way that is to say "30 minutes is really the only time today that is 100% focused on me". It isn't focused on work, dogs, family, house, band or beers with friends. So it's like, cherish this 30 minutes, get what you need out of it. If you're energy is totally zapped, then stretch, meditate, or journal. There are huge benefits to being present w/ yourself and your thoughts.