Energy cost of walking and functional aerobic capacity during moderate intensity exercise in adults with obstructive sleep apnea: a cross-sectional study

Background: Autonomic dysregulation associated with obstructive sleep apnea (OSA) may limit cardiopulmonaryresponses to exercise, which, in turn, may impair functional aerobic capacity (FAC) and walking economy. Weaimed to characterize walking economy and FAC in OSA patients compared with healthy adults (non-OSA) andexamine their relationship with OSA severity (apnea-hypopnea index [AHI]). Methods: A total of 26 adults (OSA,n= 13; non-OSA,n= 13) participated in this cross-sectional study. In this study,the participants with OSA were between the ages of 25 and 60 years, with a body mass index of 25 kg/m2to 39 kg/m2, and who had undergone a recent third-party sleep study with an AHI of 5 or greater. Participants completed amaximal integrated cardiopulmonary exercise test, three separate exercise bouts of constant work rate (CWR)treadmill test at 85% of anaerobic threshold (AT), and a 10-min walk test (10MWT). Multiple linear regressionanalysis corrected for weight, age, and BMI were performed to examine the associations. Results:There were significant differences between OSA and non-OSA participants in VO2peak(29.7 ± 5.6 mL/kg/minvs. 37.5 ± 6.5 mL/kg/min,p= 0.03) and Net VO2during CWR (12.7 ± 5 vs.19 ± 6 mL/kg/min,p= 0.02). The 10MWTspeed and distance were significantly lower in the OSA group (allp\u3c 0.001). The energy cost of walking duringsubmaximal exercise and 10-min walk test was higher among patients with OSA (allp\u3c 0.001). The AHI scores wereassociated with 10MWT distance (R2= 0.85,p\u3c 0.001), energy cost of walking (R2= 87,p\u3c 0.001), and VO2atanaerobic threshold (R2= 0.92,p\u3c 0.001). Conclusions:The findings of this study show that patients with OSA have reduced FAC and a higher energy cost ofwalking. AHI explained 87% of variance in the energy cost of walking during the 10MWT. The results suggest that individuals with more severe obstructive sleep apnea experience greater impairment in functional performance

Toward a Method of Collaborative, Evidence-Based Response to Desertification

Over generalized narratives about how desertified ecosystems will respond to restoration actions may result in wasted resources, missed opportunities, or accelerated degradation. Evidence-based collaborative adaptive management (CAM) could solve this problem by providing site-specific information that is trusted by users and enables learning opportunities. Although calls for CAM are increasing, many recommendations remain abstract and difficult to operationalize in specific projects. We review some general challenges for managing desertification in rangelands and draw upon recommendations in the recent literature to develop a 6-step method of CAM to address desertification. The method draws upon our ongoing experiences and makes novel connections between CAM concepts and technologies including ecological sites, state-and-transition models, ecological state mapping, and web-based knowledge systems. The development of a broadly-applicable and flexible methodology for CAM could increase the frequency and success of projects and provide sorely needed knowledge to guide locally-tailored responses to desertification

Leptin, Leptin Soluble Receptor, and the Free Leptin Index following a Diet and Physical Activity Lifestyle Intervention in Obese Males and Females

Leptin (LEP) is associated with appetite regulation and metabolism. Concentration is linear with adiposity, suggesting LEP resistance. LEP circulates freely and bound with its soluble receptor (sOB-r); the ratio is the free leptin index (FLI), an index of leptin resistance; lower FLI suggests reduced biological action. Purpose. The aim was to determine the effect of changes in adipose tissue distribution on LEP, sOB-r, and FLI following 6 months (6 M) of a diet/exercise weight loss program (WLP). In addition, we aim to identify predictors of the FLI. Methods. 6 M WLP consisted of diet/lifestyle interventions following ADA guidelines. Body composition was assessed by DXA. LEP and sOB-r analysis were done via ELISA. Results. 10 adults completed the WLP. Significant reductions were seen in total fat percentage (% fat), nontrunk fat, (NTF), and trunk fat (TF) from base to 3 m and 6 M (p≤0.05). The FLI were reduced at 3 M and 6 M for males and 6 M for females. Total body fat and body weight predicted the FLI in both sexes. Conclusions. LEP and FLI reductions following 6 M of WLP were achieved independent of sOB-r changes. We also demonstrate that the FLI can be predicted noninvasively through total fat mass and body weight in kilograms

A clarion call for aeolian research to engage with global land degradation and climate change

This editorial represents a clarion call for the aeolian research community to provide increased scientific input to the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Convention to Combat Desertification (UNCCD) and an invitation to apply for ISAR funding to organize a working group to support this engagement

Indicators and Benchmarks for Wind Erosion Monitoring, Assessment and Management

Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management

Incorporating Hydrologic Data and Ecohydrologic Relationships into Ecological Site Descriptions

The purpose of this paper is to recommend a framework and methodology for incorporating hydrologic data and ecohydrologic relationships in Ecological Site Descriptions (ESDs) and thereby enhance the utility of ESDs for assessing rangelands and guiding resilience-based management strategies. Resilience-based strategies assess and manage ecological state dynamics that affect state vulnerability and, therefore, provide opportunities to adapt management. Many rangelands are spatially heterogeneous or sparsely vegetated where the vegetation structure strongly influences infiltration and soil retention. Infiltration and soil retention further influence soil water recharge, nutrient availability, and overall plant productivity. These key ecohydrologic relationships govern the ecologic resilience of the various states and community phases on many rangeland ecological sites (ESs) and are strongly affected by management practices, land use, and disturbances. However, ecohydrologic data and relationships are often missing in ESDs and state-and-transition models (STMs). To address this void, we used literature to determine the data required for inclusion of key ecohydrologic feedbacks into ESDs, developed a framework and methodology for data integration within the current ESD structure, and applied the framework to a select ES for demonstrative purposes. We also evaluated the utility of the Rangeland Hydrology and Erosion Model (RHEM) for assessment and enhancement of ESDs based in part on hydrologic function. We present the framework as a broadly applicable methodology for integrating ecohydrologic relationships and feedbacks into ESDs and resilience-based management strategies. Our proposed framework increases the utility of ESDs to assess rangelands, target conservation and restoration practices, and predict ecosystem responses to management. The integration of RHEM technology and our suggested framework on ecohydrologic relations expands the ecological foundation of the overall ESD concept for rangeland management and is well aligned with resilience-based, adaptive management of US rangelands. The proposed enhancement of ESDs will improve communication between private land owners and resource managers and researchers across multiple disciplines in the field of rangeland management

Enhancing wind erosion monitoring and assessment for U.S. rangelands

Wind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production, and air quality. Despite its significance, little is known about which landscapes are eroding, by how much, and when. The National Wind Erosion Research Network was established in 2014 to develop tools for monitoring and assessing wind erosion and dust emissions across the United States. The Network, currently consisting of 13 sites, creates opportunities to enhance existing rangeland soil, vegetation, and air quality monitoring programs. Decision-support tools developed by the Network will improve the prediction and management of wind erosion across rangeland ecosystems. © 2017 The Author(s)The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

A Comparison of Approaches to Regional Land-Use Capability Analysis for Agricultural Land-Planning

Smallholder agriculture is a major source of income and food for developing nations. With more frequent drought and increasing scarcity of arable land, more accurate land-use planning tools are needed to allocate land resources to support regional agricultural activity. To address this need, we created Land Capability Classification (LCC) system maps using data from two digital soil maps, which were compared with measurements from 1305 field sites in the Dosso region of Niger. Based on these, we developed 250 m gridded maps of LCC values across the region. Across the region, land is severely limited for agricultural use because of low available water-holding capacity (AWC) that limits dry season agricultural potential, especially without irrigation, and requires more frequent irrigation where supplemental water is available. If the AWC limitation is removed in the LCC algorithm (i.e., simulating the use of sufficient irrigation or a much higher and more evenly distributed rainfall), the dominant limitations become less severe and more spatially varied. Finally, we used additional soil fertility data from the field samples to illustrate the value of collecting contemporary data for dynamic soil properties that are critical for crop production, including soil organic carbon, phosphorus and nitrogen. View Full-Text</div