I think your last point may be the most motivational one for employers to support extra physical activity. Improved performance can be measurable in terms of 'added value' per hour at work. Ten minutes of exercise every hour or so might look costly in terms of time lost but would ultimately have a beneficial effect on the bottom line. Exercise helps reduce the stress levels and so helps clear the mind, enhance focus and enables people to collaborate better with one another. productivity rises as a result.