Physical Activity and Modernization among Bolivian Amerindians

Abstract

BackgroundPhysical inactivity is a growing public health problem, and the fourth leading risk factor for global mortality. Conversely, indigenous populations living traditional lifestyles reportedly engage in vigorous daily activity that is protective against non-communicable diseases. Here we analyze physical activity patterns among the Tsimane, forager-horticulturalists of Amazonian Bolivia with minimal heart disease and diabetes. We assess age patterns of adult activity among men and women, test whether modernization affects activity levels, and examine whether nascent obesity is associated with reduced activity.Methods and FindingsA factorial method based on a large sample of behavioral observations was employed to estimate effects of age, sex, body mass index, and modernization variables on physical activity ratio (PAR), the ratio of total energy expenditure to basal metabolic rate. Accelerometry combined with heart rate monitoring was compared to the factorial method and used for nighttime sampling. Tsimane men and women display 24 hr physical activity level (PAL) of 2.02–2.15 and 1.73–1.85, respectively. Little time was spent “sedentary”, whereas most activity was light to moderate, rather than vigorous. Activity peaks by the late twenties in men, and declines thereafter, but remains constant among women after the early teens. Neither BMI, fat free mass or body fat percentage are associated with PAR. There was no negative effect of modernization on physical activity.ConclusionsTsimane display relatively high PALs typical of other subsistence populations, but of moderate intensity, and not outside the range of developed populations. Despite rapidly increasing socioeconomic change, there is little evidence that total activity has yet been affected. Overweight and obesity are more prevalent among women than men, and Spanish fluency is associated with greater obesity in women. The lack of cardiovascular disease among Tsimane is unlikely caused by activity alone; further study of diet, food intake and infectious disease is needed.

High resting metabolic rate among Amazonian forager‐horticulturalists experiencing high pathogen burden

“…Physical activity was measured by accelerometry counts based on a three-day sample with an Actigraph GT3X accelerometer (Actigraph LLC, Pensacola, FL) in a subset of participants (n=28) in order to assess the relative impact of physical activity on TEE (see Gurven et al 2013 for additional details).…”

Modernization is associated with intensive breastfeeding patterns in the Bolivian Amazon

“…Time allocation studies indicate that Tsimane women spend roughly 2 hours/day in direct productive tasks such as agricultural work and an additional 4-6 hours per day engaged in domestic tasks including childcare (Gurven et al, 2013). Gurven and colleagues used the factorial method (FAO/WHO/UNU, 1985) in conjunction with accelerometry and heart rate monitoring (Assah et al, 2011) to construct 24-hour physical activity level estimates (PAL) for Tsimane men and women.…”

“…They found that 24-hour PAL for Tsimane women (aged 20+) was 1.73. This PAL is categorized as “moderate to active” (FAO/WHO/UNU, 2004) and is only slightly higher than the mean PAL for women in industrialized societies (1.71), but slightly lower than that of women from other hunting and gathering or farming groups (Dugas et al, 2011; Gurven et al, 2013). …”

Adaptive Capacity: An Evolutionary Neuroscience Model Linking Exercise, Cognition, and Brain Health

“…Based on analyses of modern human hunting and gathering populations [39,43], it is likely that foraging occurs at moderate aerobic intensities (~40–85% of maximum aerobic capacity) over long time periods, and thus, we might expect that physiological adaptations are tuned to this range of intensities. Since humans never had to adapt to long periods of inactivity, including very low amounts of moderate intensity activity, our physiological response to long-term inactivity can lead to chronic disease [26], and this may be especially relevant in the context of cognitive and brain aging.…”