Lifestyle and patterns of physical activity in Hadza foragers

Abstract

Objectives: Physically active lifestyles are associated with several health benefits. Physical activity (PA) levels are low in post-industrial populations, but generally high throughout life in subsistence populations. The Hadza are a subsistence-oriented foraging population in Tanzania known for being physically active, but it is unknown how recent increases in market integration may have altered their PA patterns. In this study, we examine PA patterns for Hadza women and men who engage in different amounts of traditional foraging.

Materials and methods: One hundred and seventy seven Hadza participants (51% female, 19-87 years) wore an Axivity accelerometer (dominant wrist) for ~6 days during dry season months. We evaluated the effects of age, sex, and lifestyle measures on four PA measures that capture different aspects of the PA profile.

Results: Participants engaged in high levels of both moderate-intensity PA and inactivity. Although PA levels were negatively associated with age, older participants were still highly active. We found no differences in PA between participants living in more traditional "bush" camps and those living in more settled "village" camps. Mobility was positively associated with step counts for female participants, and schooling was positively associated with inactive time for male participants.

Conclusions: The similarity in PA patterns between Hadza participants in different camp types suggests that high PA levels characterize subsistence lifestyles generally. The sex-based difference in the effects of mobility and schooling on PA could be a reflection of the Hadza's gender-based division of labor, or indicate that changes to subsistence-oriented lifestyles impact women and men in different ways.

Keywords: Hadza hunter-gatherers; MVPA; accelerometry; physical activity; step counts.

Figure 1.. Physical Activity Measures by Age and Sex for Hadza participants.

Each filled orange circle represents one Hadza female participant (ages 19 to 87 years), and one filled blue circle represents one Hadza male participant (ages 19 to 86 years). Orange and blue lines represent a generalized linear model for female and male participants, respectively. Gray shaded area represents the 95% confidence interval for the regression line. Physical activity measures here are derived from wrist-worn accelerometers, and represent average daily (a) time (minutes) spent in moderate-to-vigorous physical activity (MVPA); (b) percent of MVPA time spent in moderate-intensity activities; (c) step count; (d) time (hours) spent inactive.

Figure 2.. Effects of Age, Sex, and Foraging and Lifestyle Variables on Physical Activity Measures.

Beta coefficient plots represent results from generalized linear models, stratified by sex. Results of models with female participants are on the left of each panel, and results of models with male participants are on the right of each panel. Blue circles represent a positive beta coefficient, and red circles represent a negative beta coefficient. Unfilled circles represent a non-significant effect, and filled circles represent a significant effect, after FDR adjustment. Panels represent beta coefficient plots for average daily (a) time (minutes) spent in moderate-to-vigorous physical activity (MVPA); (b) percent of MVPA time spent in moderate-intensity activities; (c) step count; (d) time (hours) spent inactive.

Figure 3.. Proportion of Waking Hours spent in different levels of activity intensities for Hadza female (left panel) and male (right panel) participants.

Yellow shaded area represents proportion of waking hours spent inactive; blue shaded area represents proportion of waking hours spent in light-intensity activities; green shaded area represents proportion of waking hours spent in moderate-intensity activities; and pink shaded area represents proportion of waking hours spent in vigorous-intensity activities.