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Abstract Background and objectivesPregnancy, heat stress, and physical activity (PA) are all known to independently increase human water requirements. We hypothesize that climate conditions and behavioral strategies interact to shape water needs in highly active pregnancies. MethodologyWe recruited 20 female endurance runners who were pregnant (8–16 weeks gestational age; n = 13) or planning to be pregnant (n = 7) for an observational, prospective cohort study. At three timepoints in the study (preconception, 8–16 weeks, and 32–35 weeks), we measured water turnover (WT) using the deuterium dilution and elimination technique, PA using ActiGraph wGT3X-BT accelerometers, and heat index (HI) using historical temperature and humidity data. We also compared athletes to nonathletes from a previously published study. ResultsAthletes maintained high WT from preconception through the end of pregnancy. PA was positively associated with WT among athletes for preconception and early pregnancy time periods but not for the third trimester. HI weakly moderated the relationship between PA and WT in predicting a more positive slope in hotter and more humid weather conditions. WT in athletes was higher than in nonathletes, but this difference attenuated during the third trimester, as nonathletes increased their WT. Conclusions and implicationsAthletes experience higher WT with greater levels of PA, and this relationship is somewhat stronger in higher HI conditions. With the threat of climate change expected to exacerbate extreme heat conditions, evidence-based, global policies are required for particularly vulnerable populations. 

Abstract Background and objectivesWater is essential for proper physiological function. As temperatures increase, populations may struggle to meet water needs despite adaptations or acclimation; chronic dehydration can cause kidney damage. We evaluate how daily water requirements are associated with ambient temperature (ambT), wet bulb globe temperature (WBGT), urine specific gravity (USG; marker of hydration status), and albumin:creatinine ratio (ACR; kidney function biomarker) among Daasanach pastoralists living in a hot, dry northern Kenyan climate. MethodologyWater turnover (WT), USG, and ACR were measured using deuterium depletion (WT), refractometry (USG), and urine dipstick (ACR) for 76 participants aged 5–68 years in June 2022–23. Relationships between WT, ambT, WBGT, USG, and ACR were evaluated using linear and generalized linear models. ResultsAdult WT was higher than mean values worldwide, peaking around 7 l/day. Water demands increase from childhood through middle age before falling in later life. Adult WT was not correlated with ambT or WBGT. About 2/11 children’s and 7/36 adults’ USG indicated dehydration; USG was not correlated with child WT but was negatively correlated with adult WT when accounting for body size. WT was lower among adults with high (≥30 mg/g) ACR; high ACR was associated with higher USG. Conclusions and implicationsHigh Daasanach WT is likely driven by hot, semi-arid conditions, and lifestyle, rather than by compromised kidney function. Most participants were well-hydrated. Despite nonsignificant correlations between temperature and adult WT, high WT highlights the physiological demands of hot, dry climates. As climate change increases the global population exposed to hotter temperatures, global water needs will likely increase. 

ABSTRACT ObjectivesIn subsistence populations, high physical activity is typically maintained throughout pregnancy. Market integration shifts activity patterns to resemble industrialized populations, with more time allocated to sedentary behavior. Daasanach semi‐nomadic pastoralists living in northern Kenya face lifestyle heterogeneity due to the emergence of a market center. We investigate how Daasanach women manage the energetic demands of pregnancy with subsistence labor tasks and how market integration relates to variation in energetic demands, physical activity, and coping strategies. MethodsWe conducted nine focus group discussions with 72 pregnant women. We also deployed wrist‐worn fitness trackers with 21 pregnant women in two community types: central or peripheral to the market center to capture variation in market integration. Data from focus group discussions were analyzed using thematic analysis. We used multiple linear regression to examine the relationship between gestational age and physical activity. ResultsWe identified themes of increased fatigue, diet restrictions, and assistance with labor tasks during pregnancy. Gestational age negatively predicted mean daily steps, with a decrease of 1160 ± 437 steps per day with each consecutive pregnancy month. Stratified by community type, gestational age only negatively predicted mean daily steps for peripheral communities, with a decrease of 1443 ± 629 steps per day with each consecutive pregnancy month. ConclusionsResults suggest that physical activity differs with market integration early, but not late, in pregnancy. Daasanach women cope with the energetic demands of pregnancy by reducing physical activity late in pregnancy and receiving assistance with labor tasks from family and neighbors. 

Background: Pastoralists live in challenging environments, which may be accompanied by unique activity, energy, and water requirements. Aim: Few studies have examined whether the demands of pastoralism contribute to differences in total energy expenditure (TEE) and water turnover (WT) compared to other lifestyles. Subjects and methods: Accelerometer-derived physical activity, doubly labelled water-derived TEE and WT, and anthropometric data were collected for 34 semi-nomadic Daasanach adults from three northern Kenyan communities with different levels of pastoralist activity. Daasanach TEEs and WTs were compared to those of other small-scale and industrialised populations. Results: When modelled as a function of fat-free-mass, fat-mass, age, and sex, TEE did not differ between Daasanach communities. Daasanach TEE (1564–4172 kcal/day) was not significantly correlated with activity and 91% of TEEs were within the range expected for individuals from comparison populations. Mean WT did not differ between Daasanach communities; Daasanach absolute (7.54 litres/day men; 7.46 litres/day women), mass-adjusted, and TEE-adjusted WT was higher than most populations worldwide. Conclusions: The similar mass-adjusted TEE of Daasanach and industrialised populations supports the hypothesis that habitual TEE is constrained, with physically demanding lifestyles necessitating trade-offs in energy allocation. Elevated WT in the absence of elevated TEE likely reflects a demanding active lifestyle in a hot, arid climate. 

BACKGROUND:Salt leaching into freshwater is an emerging global environmental health concern. We tested the associations between drinking water salinity and blood pressure, hypertension, and albuminuria. METHODS:We conducted a 2-year panel study in 2022 and 2023 with 434 observations among 327 Daasanach adults aged >18 years in northern Kenya. Water sources were analyzed for overall salinity and ionic composition (sodium; chloride; calcium, potassium, magnesium). We measured resting blood pressure and classified hypertension stage 1 and stage 2. Urine samples were analyzed for albuminuria (≥30 mg/g albumin-to-creatinine ratio). RESULTS:Drinking water salinity was driven by sodium-chloride (mean=162.6 mg/L, SD=77.1), with low concentrations of calcium, potassium, and magnesium (mean=45 mg/L, SD=13.5). Across 2022 and 2023, 40.1% of adults had at least hypertension stage 1, 13.5% had hypertension stage 2, and 42.2% had albuminuria. Using random effects linear and logistic panel regressions fully adjusted for confounders, each 100 mg/L of drinking water sodium-chloride was associated with 4.5 mm Hg (95% CI, 2.4–6.6) and 3.3 mm Hg (95% CI, 2.2–4.5) increases in systolic and diastolic blood pressure, 3.0× the odds of at least hypertension stage 1 (95% CI, 1.49–5.83), 3.6× the odds of hypertension stage 2 (95% CI, 1.93–6.81), and 2.0× the odds of albuminuria (95% CI, 1.28–3.06). Calcium, potassium, and magnesium were unassociated with any outcomes. Hypertension stage 2 (but not hypertension stage 1) was associated with 2.6× (95% CI, 1.19–5.77) the odds of albuminuria. CONCLUSIONS:Drinking water sodium-chloride was associated with resting blood pressure, hypertension, and albuminuria in a population with few traditional lifestyle risk factors for chronic disease. Measuring specific salts in water helps untangle associations with hypertension. 

ABSTRACT ObjectiveExtreme climatic events, like droughts, are increasing in frequency and severity. Droughts disrupt community livelihoods and resources with serious implications for human biology. This study investigated how chronic stress, measured by fingernail cortisol concentration (FCC), and water insecurity status were predictive of C‐reactive protein (CRP), a biomarker of inflammation, during a historic drought among Daasanach seminomadic pastoralists. MethodsData were collected at the height of the 2022 drought from 128 Daasanach household heads aged 16–80 years in northern Kenya using household surveys, anthropometric measurements, and dried blood spots to assess CRP levels and fingernails to assess FCC. We employed mixed‐effects linear and logistic regression models to examine the relationships between log‐transformed FCC, high water insecurity status measured via the Household Water Insecurity Experiences (HWISE ≥ 24) scale, and serum‐equivalent CRP (log‐transformed and dichotomized at mild, low‐grade inflammation ≥ 1 mg/L) adjusted for covariates. ResultsThe mean serum‐equivalent CRP was 4.1 mg/L and 56.3% of Daasanach adults had at least mild, low‐grade inflammation. Linear models indicated that ln(FCC) was positively associated with ln(CRP) (β = 0.56, SE = 0.12;p < 0.001). Further, logistic models demonstrated that ln(FCC) (OR = 2.69, 95% CI: 1.84–3.95;p < 0.001) and high water insecurity (OR = 2.23, 95% CI: 1.34–3.72;p = 0.002) were both associated with greater odds of low‐grade inflammation. ConclusionThis study provides evidence for how chronic stress and severe water insecurity may impact inflammation levels among pastoralists during drought. Since inflammation is central to cardiometabolic disease etiology, this is an additional reason to mitigate the negative health impacts of droughts and water insecurity exacerbated by climate change.