Accordance between V̇O 2 max and behavior in Ngisonyoka Turkana

To determine age-related changes in biologically available testosterone (T) among men in a subsistence society and their relationship to energetic status, T, sex hormone binding globulin (SHBG) and anthropometric measures were compared among nomadic and settled Turkana pastoralists of northern Kenya. Hormonal measures were available for 104 nomadic men and 72 settled men, estimated ages 20-90 years. Comparison of the two subpopulations revealed significantly higher blood T (32.7+/- 15.1 vs. 23.4+/-15.2 nM) and SHBG (53.8+/- 19.5 vs. 39.7+/- 20.nM) but not free testosterone index (FTI) (65.6+/- 39.3 vs.66.3+/- 45.9) among the nomads. Total blood T did not exhibit a significant linear decline with age in either subgroup, while SHBG values showed a significant linear increase among the nomads. When controlled for energetic status, FTI showed a significant decrease with age among the nomads, but not the settled males. Total blood T was negatively associated with waist circumference among the nomads, but not the settled males. FTI showed a marginally significant negative association with waist circumference, suprailiac skinfold, and % body fat among the nomads but no associations with body composition among the settled group. These results add additional evidence that T is related to energetic status under conditions of negative energy balance and suggest that cross-population variation in the slope of age-related declines in free serum T and salivary T may be related to energetic status through the effects of SHBG.

Section: Other Possible Factors Related To Hormonal Statusmentioning

confidence: 88%

Age‐related changes in testosterone and SHBG among Turkana males

Leslie

Campbell

2005

“…Delayed development in food-limited populations has been well documented (Shephard, 1978;Little and Johnson, 1986;Curran-Everett, 1994). Whereas studies in food-abundant populations demonstrate greatest isometric muscle strength in the late teens (i.e., Swedes in Bäckman et al, 1995), undernourished traditional populations like the Ache tend to demonstrate performance peaks in the early-to mid-20s.…”

Section: Discussionmentioning

confidence: 99%

Modeling growth and senescence in physical performance among the ache of eastern paraguay

Walker

Hill

2003

This article seeks to partially fill a paucity of available data on physical performance in hunter-gatherer societies. Quantitative data are presented on various physical performance measures conducted on the Ache of eastern Paraguay, hunter-gatherers up to the 1970s and now part-time foragers and horticulturists. The performance battery was conducted on most individuals over 10 years of age, allowing for cross-sectional examination of growth and senescence patterns across the lifespan for both sexes. These measures tend to display steep ascents and peak in the early 20s with slight declines thereafter with age for males, whereas females demonstrate peaks in performance earlier in life, with lower or no senescence rates thereafter. The result is a convergence in physical performance between men and women at later ages. We suggest that the female physiology faces reproductive constraints to performance early in life but shifts allocation to increased work output later in life during the long human postmenopausal stage. In contrast, the male physiology maximizes work output in early adult life. These schedules of physical performance are contrasted with schedules of food production ability, which tend to occur later in life, and therefore imply that skill rather than strength alone is an important component of the human foraging niche.

“…The few studies that have examined cardiovascular fitness in subsistence populations show mixed evidence for a decline in fitness with age. Turkana men engaging in pastoralism do not exhibit a consistent decline in VO 2 max by age 45 (Curran‐Everett, ). Ache women living on a reservation and practicing a combination of gathering and horticulture do not exhibit a decline in cardiovascular fitness by age 60 (Walker and Hill, ).…”

mentioning

confidence: 99%

Patterns of senescence in human cardiovascular fitness: VO₂max in subsistence and industrialized populations

Pisor

Gurven

Blackwell

et al. 2013

Objectives This study explores whether cardiovascular fitness levels and senescent decline are similar in the Tsimane of Bolivia and Canadians, as well as other subsistence and industrialized populations. Among Tsimane, we examine whether morbidity predicts lower levels and faster decline of cardiovascular fitness, or whether their lifestyle (e.g., high physical activity) promotes high levels and slow decline. Alternatively, high activity levels and morbidity might counterbalance such that Tsimane fitness levels and decline are similar to those in industrialized populations. Methods Maximal oxygen uptake (VO2max) was estimated using a step test heart rate method for 701 participants. We compared these estimates to the Canadian Health Measures Survey and previous studies in industrialized and subsistence populations. We evaluated whether health indicators and proxies for market integration were associated with VO2max levels and rate of decline for the Tsimane. Results The Tsimane have significantly higher levels of VO2max and slower rates of decline than Canadians; initial evidence suggests differences in VO2max levels between other subsistence and industrialized populations. Low hemoglobin predicts low VO2max for Tsimane women while helminth infection predicts high VO2max for Tsimane men, though results might be specific to the VO2max scaling parameter used. No variables tested interact with age to moderate decline. Conclusions The Tsimane demonstrate higher levels of cardiovascular fitness than industrialized populations, but levels similar to other subsistence populations. The high VO2max of Tsimane is consistent with their high physical activity and few indicators of cardiovascular disease, measured in previous studies.