Set aside 30 minutes a day to walk. Take 15 minutes at 10am and another 15 at 3 pm. Our bodies were not meant to sit for extended periods of time. Our brains do not function to their full capacity after sitting that long. You can manage your job and your body, take charge of them. Take a walk meeting, and integrate the two necessities.
Working out intensely has been proven to tax your system. Try adding blood circulating intervals into your routine. Take charge oxygenating your body that was not designed to sit hunched over a desk all day.