You havesomepeople who areworkingall the heavy traffic all the timeandotherpeople working hardly any traffic, and that doesn't make for good controllers, in terms ofkeeping up the proficiency.
The American Heart Association recommends reducing time spent in heavy traffic or jogging during rush hour, or near busy roadways and better treatment for cardiovascular risk factors.
VOA: standard.2010.08.04
From Monday the timetable will change to allow for the extra time drivers need during heavytraffic.