"less physically demanding" is just not the right way of putting it. Carpal tunnel, back problems, issues with core strength, general lethargy, are all issues that can happen when you're spending this much time doing one thing, especially when it exacts a heavy mental toll, not even including all of the mental health/physical manifestations of depression and anxiety that can result from overworking in any profession, let alone one of the most stressful in the world.