Short bouts of exercise are better than no exercise
Many professions have time requirements that are near to impossible to maintain a healthy lifestyle. There are no many of them that can match up with the life of a physician. I wake at 05:00 or 5:00 AM in no earlier to report to work within an hour, and I am lucky if I get home by 1830 or 6:30 PM. The lifestyle of a physician in nonstop with limited time for exercise or eating meals during the day.
This type of lifestyle does not eliminate the possibility of exercise. You can get exercise in short bouts and stay in shape. I exercise 10 minutes 3-6 times a day to get my 30-60 minutes 5 days a week.
The bottom line: You do not need to get 30-60 minutes of sustained exercise to be healthy or sustain health. Sure, it is better to get 30-60 minutes of exercise, but some is better than none. If you work in a building with stairs, take them between meetings.