15 research outputs found
The Effect of Lower-Body Positive Pressure on the Cardiorespiratory Response at Rest and during Submaximal Running Exercise.
Anti-gravity treadmills facilitate locomotion by lower-body positive pressure (LBPP). Effects on cardiorespiratory regulation are unknown. Healthy men (30 ± 8 y, 178.3 ± 5.7 cm, 70.3 ± 8.0 kg; mean ± SD) stood upright ( javax.xml.bind.JAXBElement@57c008e9 = 10) or ran ( javax.xml.bind.JAXBElement@7a503138 = 9) at 9, 11, 13, and 15 km.h javax.xml.bind.JAXBElement@189f9fd6 (5 min stages) with LBPP (0, 15, 40 mmHg). Cardiac output (CO), stroke volume (SV), heart rate (HR), blood pressure (BP), peripheral resistance (PR), and oxygen uptake (VO javax.xml.bind.JAXBElement@270f0b82 ) were monitored continuously. During standing, LBPP increased SV [by +29 ± 13 (+41%) and +42 ± 15 (+60%) ml, at 15 and 40 mmHg, respectively ( javax.xml.bind.JAXBElement@705fd8ca < 0.05)] and decreased HR [by -15 ± 6 (-20%) and -22 ± 9 (-29%) bpm ( javax.xml.bind.JAXBElement@bfdfe08 < 0.05)] resulting in a transitory increase in CO [by +1.6 ± 1.0 (+32%) and +2.0 ± 1.0 (+39%) l.min javax.xml.bind.JAXBElement@6ff8b18e ( javax.xml.bind.JAXBElement@3074f4e8 < 0.05)] within the first seconds of LBPP. This was accompanied by a transitory decrease in end-tidal PO javax.xml.bind.JAXBElement@3e63f3a4 [by -5 ± 3 (-5%) and -10 ± 4 (-10%) mmHg ( javax.xml.bind.JAXBElement@5a8a47de < 0.05)] and increase in VO javax.xml.bind.JAXBElement@7054e9c0 [by +66 ± 53 (+26%) and +116 ± 64 (+46%) ml.min javax.xml.bind.JAXBElement@67908096 ( javax.xml.bind.JAXBElement@464fa113 < 0.05)], suggesting increased venous return and pulmonary blood flow. The application of LBPP increased baroreflex sensitivity (BRS) [by +1.8 ± 1.6 (+18%) and +4.6 ± 3.7 (+47%) at 15 and 40 mmHg LBPP, respectively javax.xml.bind.JAXBElement@4e73aab3 < 0.05]. After reaching steady-state exercise CO vs. VO javax.xml.bind.JAXBElement@19be4054 relationships remained linear with similar slope and intercept for each participant (mean javax.xml.bind.JAXBElement@7ac9e7c5 javax.xml.bind.JAXBElement@41b586b6 = 0.84 ± 0.13) while MAP remained unchanged. It follows that (1) LBPP affects cardiorespiratory integration at the onset of exercise; (2) at a given LBPP, once reaching steady-state exercise, the cardiorespiratory load is reduced proportionally to the lower metabolic demand resulting from the body weight support; (3) the balance between cardiovascular response, oxygen delivery to the exercising muscles and blood pressure regulation is maintained at exercise steady-state; and (4) changes in baroreflex sensitivity may be involved in the regulation of cardiovascular parameters during LBPP
Recommended from our members
Utility and state industrial EMS incentives programs: Experience and success factors
This paper summarizes the results of a survey of utility and state demand-side management (DSM) programs that address efficient motor systems. The paper discusses the incentive structures in place at both the state and utility levels to encourage efficient motor systems, and the market barriers associated with implementation of efficient motor equipment. The paper also assesses how the current incentives might address the market barriers to the implementation of efficient motor systems
Recommended from our members
Fort Irwin National Training Center integrated resource assessment. Volume 1: Executive summary
Some of the most difficult problems encountered at federal sites in reducing energy consumption in a cost-effective manner revolve around understanding where energy is being used and what technologies can be employed to decrease energy use. Many large federal sites have one or two meters to track electric energy use for several thousand buildings and numerous industrial processes. Even where meters are available on individual buildings or family housing units, the meters are not consistently read. When the federal energy manager has been able to identify high energy users, the energy manager may not have the background, training, or resources to determine the most cost-effective options for reducing this energy use. This limitation can lead to selection of suboptimal projects that prevent the site from achieving full life-cycle cost savings. The U.S. Department of Energy (DOE) Federal Energy Management Program (FEMP) has been tasked by the U.S. Army Forces Command (FORSCOM) to identify, evaluate, and acquire all cost-effective energy projects at selected federal facilities. Pacific Northwest Laboratory (PNL) is assisting FEMP in this effort. This is part of a model program that PNL has developed to provide a systematic approach to evaluating energy opportunities. The program (1) identifies the building groups and end uses using the most energy (not just having the greatest energy-use intensity), and (2) evaluates the numerous options for retrofit or installation of new technology that will result in the selection of the most cost-effective technologies. In essence, this model program provides the federal energy manager with a road map to significantly reduce energy use in a planned, rational, cost-effective fashion that is not biased by the constraints of the typical funding sources available to federal sites
The menthol receptor TRPM8 is the principal detector of environmental cold
Sensory nerve fibres can detect changes in temperature over a remarkably wide range, a process that has been proposed to involve direct activation of thermosensitive excitatory transient receptor potential (TRP) ion channels. One such channel--TRP melastatin 8 (TRPM8) or cold and menthol receptor 1 (CMR1)--is activated by chemical cooling agents (such as menthol) or when ambient temperatures drop below approximately 26 degrees C, suggesting that it mediates the detection of cold thermal stimuli by primary afferent sensory neurons. However, some studies have questioned the contribution of TRPM8 to cold detection or proposed that other excitatory or inhibitory channels are more critical to this sensory modality in vivo. Here we show that cultured sensory neurons and intact sensory nerve fibres from TRPM8-deficient mice exhibit profoundly diminished responses to cold. These animals also show clear behavioural deficits in their ability to discriminate between cold and warm surfaces, or to respond to evaporative cooling. At the same time, TRPM8 mutant mice are not completely insensitive to cold as they avoid contact with surfaces below 10 degrees C, albeit with reduced efficiency. Thus, our findings demonstrate an essential and predominant role for TRPM8 in thermosensation over a wide range of cold temperatures, validating the hypothesis that TRP channels are the principal sensors of thermal stimuli in the peripheral nervous system