Very Simply, Your Priorities.
Dr. Morris makes a point to SCHEDULE physical activity into his schedule AT LEAST four days a week. That is around managing his full time private practice, his rotations in the hospital, managing his participation on the multiple health-associated boards he sits on (including the Hopewell Community Garden he founded), prioritizing family time with his wife (shall I mention his, like clock-work, weekly date with his wife?), four children and his new granddaughter, volunteering in the community and teaching tai chi, preparing his own healthful meals, walking his dog Dusty, spending time outside of work helping his patients, and much more!
Ultimately, it does not come down to who has the time and who does not. It is very SIMPLY, who prioritizes activity and their health. If you prioritize your health, you put that into your day first, and you manage everything else around it.
Dr. Morris is known saying, "There is no Morris Cardio, without Morris."