IFAL 2009/2

    “Sedentarism is an independent risk factor for coronary heart disease, osteoporosis, and cancer. However, it still lacks a consensual definition. Also unclear are the activities that differentiate active from sedentary people. In previous reports, sedentarism has been defined according to total energy expenditure or according to energy expended in walking, climbing stairs, and engaging in sports; in performing leisure-time activities, and in performing vigorous activities. Occupational activities have usually not been evaluated, despite their importance. To improve the possibility of comparisons across studies, we must establish a definition of sedentarism that will allow universal use.

    A report of the US surgeon general suggests that such a definition may be based on total energy expenditure: an increase in daily energy expenditure of approximately 150 kcal is associated with substantial health benefits, and the activity does not need to be vigorous to produce benefits. We used this conclusion as a basis for defining active persons as those expending at least 150 kcal per day in moderateintensity activities; individuals expending less than this amount were defined as sedentary.

    However, the amount of kilocalories expended depends on an individual’s basal metabolism rate and on the duration and intensity of the activity. For example, approximately 150 kcal will be expended during 40 minutes of brisk walking for an average adult woman but only 30 minutes for an average adult man. The surgeon general’s report defines moderate-intensity activities as those expending 3 to 5 metabolic equivalents, which is approximately 3 to 5 times the basal metabolism rate. For example, walking normally and engaging in household work expend 3 times the basal metabolism rate, while walking briskly and playing table tennis expend 4 times the basal metabolism rate. In the present study, we defined moderate activities as those expending 4 times or more the basal metabolism rate.

    It is currently recommended that every adult accumulate 30 minutes or more of moderate- intensity physical activity on most- and preferably all-days of the week. However, the moderate activities that would involve the greatest adherence among people older than 35 years still need to be determined.

    The present study had 2 goals. The first was to formulate, independent of the method used to calculate daily energy expenditure, a precise definition of sedentarism that would be applicable to individuals of all ages and basal metabolism rates and to both sexes. The second goal was to identify moderate- and high-intensity activities performed by active people that could be suggested in preventive guidelines. The rationale is that activities most frequently performed by active people can reasonably be adopted by a large fraction of their sedentary peers.”

(fonte : http: //www.ajph.org/cgi/reprint/89/6/862.pdf)