SEASONAL AND SEX VARIATION IN PHYSICAL-ACTIVITY LEVELS AMONG AGROPASTORALISTS IN NEPAL

Considerable attention has been devoted to variation in levels of ener gy expenditure between and within populations; these are commonly eval uated following international guidelines for grading light, moderate, and heavy physical activity levels (PAL). This study presents activity profiles by season and sex for subsistence agro-pastoralists in Nepal , comparing data for a sample of 20 men observed four times across the year with previously published data on women. Total energy expenditur e (TEE) was estimated from direct minute-by-minute observation (totali ng 1,679 h for men, 3,601 h for women) and measures of the energy cost of single tasks (117 for men, 168 for women). PAL were calculated and graded as multiples of predicted basal metabolic rate (BMR). Despite an explicitly egalitarian organization of labor, men achieved higher P AL than women (P<.0001), although according to international gradings, both men and women assume moderately heavy PAL in the winter and very heavy PAL in the monsoon. PAL were 1.88 and 2.22 x BMR for men in res pective seasons (P<.005; TEE, 11.8 MJ/d and 13.9 MJ/d) and 1.77 and 2. 0 x BMR for women (TEE, 9.1 MJ/d and 10.5 MJ/d). High TEE values resul t from time-consuming work in subsistence tasks, most of which are of moderate energy cost. Results show that the international guideline (F AO/WHO/UNU [1985]) for grading levels of energy expenditure, which ado pts discrepant sex-specific values to define thresholds for moderate o r heavy PAL, can mask significant gender variation. Male/female ratios of PAL values are suggested instead for population-level comparisons. (C) 1996 Wiley-Liss, Inc.