ASSESSMENTOF HABITUALPHYSICALACTIVITYAPART FROM OCCUPATION

Thehypothesis thathabitual physical activity protects against coronary (ischaemic) heart disease isderived fromstatistical comparisons whichshow thatincidence, prevalence, andmortality rates vary inversely withtheaverage levels ofexercise involved indifferent occupations (Morris, Heady,Raffle, Roberts, andParks, 1953). Similar findings were subsequently madeinavariety ofstudies ofoccupational groups inseveral countries (Brown, Davidson, McKeown,andWhitfield, 1957; Morris andCraw