Bioelectrical impedance variation in healthy subjects during 12 h in the supine position

2003 ◽  
Vol 22 (2) ◽  
pp. 153-157 ◽  
Author(s):  
F SLINDE
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Bioelectrical Impedance ◽  
Impedance Variation

Supine position decreases the ability of the nose to warm and humidify air

2001 ◽  
Vol 91 (6) ◽  
pp. 2459-2465 ◽  
Author(s):  
Paraya Assanasen ◽  
Fuad M. Baroody ◽  
Edward Naureckas ◽  
Julian Solway ◽  
Robert M. Naclerio
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Air Conditioning ◽  
Upright Position ◽  
Nasal Mask ◽  
Total Water ◽  
Nasal Turbinate ◽  
Dry Air ◽  
Air Volume ◽  
Water Gradient

We tested the hypothesis that decreasing nasal air volume (i.e., increasing nasal turbinate blood volume) improves nasal air conditioning. We performed a randomized, two-way crossover study on the conditioning capacity of the nose in six healthy subjects in the supine and upright position. Cold, dry air (CDA) was delivered to the nose via a nasal mask, and the temperature and humidity of air were measured before it entered and after it exited the nasal cavity. The total water gradient (TWG) across the nose was calculated and represents the nasal conditioning capacity. Nasal volume decreased significantly from baseline without changing the mucosal temperature when subjects were placed in the supine position ( P < 0.01). TWG in supine position was significantly lower than that in upright position ( P < 0.001). In the supine position, nasal mucosal temperature after CDA exposure was significantly lower than that in upright position ( P < 0.01). Our data show that placing subjects in the supine position decreased the ability of the nose to condition CDA compared with the upright position, in contrast to our hypothesis.

Direct Comparison of (Anthropometric) Methods for the Assessment of Body Composition

2020 ◽  
Vol 76 (3) ◽  
pp. 183-192
Author(s):  
Petra Golja ◽  
Tatjana Robič Pikel ◽  
Katja Zdešar Kotnik ◽  
Matjaž Fležar ◽  
Samo Selak ◽  
...  
Keyword(s):  
Body Composition ◽  
Healthy Subjects ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Regression Equations ◽  
X Ray ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Assess Body Composition ◽  
Extensive List

Objective: Several methods for the assessment of body composition exist, yet they yield different results. The present study aimed to assess the extent of these differences on a sample of young, healthy subjects. We hypothesised that differences in body composition results obtained with different methods will vary to the extent that a subject can be misclassified into different nutritional categories. Research Methods and Procedures: Underwater weighing (UWW), bioelectrical impedance analysis (BIA), anthropometry (ANT), and dual-energy X-ray absorptiometry (DXA) were used to assess body composition. An extensive list of ANT regression equations (or sets of equations) was analysed in terms of accuracy and precision relative to DXA. Results: When DXA-determined body fat (BF) values were taken as a reference, UWW overestimated BF in both genders. In contrast, BIA (measured with a given bioimpedance analyser) underestimated BF in females, although BIA-determined BF did not differ from DXA in males. A huge difference in BF estimates (8–29% for females and 6–29% for males, for DXA-determined BF of 25.5% and 13.9% for females in males, respectively) was observed across a number of ANT regression equations; yet, ANT proved not to be inferior to DXA, provided that regression equations with the highest combinations of accuracy and precision were chosen. Conclusions: The study proved grounds for comparison of body composition results of young, healthy subjects, obtained with different methods and across a wide range of ANT regression equations. It also revealed a list of the most appropriate ANT regression equations for the selected sample and reported their accuracy and precision.

Influence of posture on left ventricular long- and short-axis shortening

2002 ◽  
Vol 283 (4) ◽  
pp. H1302-H1306 ◽  
Author(s):  
Patrik Sundblad ◽  
Bengt Wranne
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Upright Position ◽  
Lateral Part ◽  
Short Axis ◽  
Spherical Form ◽  
End Diastolic Volume ◽  
Axis Length

End-diastolic volume and left ventricular stroke volume are increased in the supine compared with upright position, but the contribution of long-axis (LAS) and short-axis shortening (SAS) to these changes with change in posture has not been established. We examined long- and short-axis motion and dimensions with echocardiography in 10 healthy subjects in the upright and supine position. Long-axis length at end diastole was almost identical, whereas the diastolic short-axis diameter was increased in the supine position. At end systole, there was a decreased long-axis length and increased short-axis length in the supine vs. upright position. Both LAS and SAS were enhanced in supine vs. upright positions [LAS: 9.3 ± 2.2 vs. 15.1 ± 3.1 mm ( P < 0.001); SAS: 12.7 ± 3.2 vs. 16.3 ± 2.8 mm ( P < 0.001)], presumably via Starling mechanisms. LAS increased more in the lateral part of the mitral annulus than in the septal part [7.7 ± 2.6 vs. 4.0 ± 2.8 mm ( P < 0.006)], which implies that the more spherical form, in the supine position, induces more stretch at the lateral free wall than in the ventricular septum. These findings support the notion that Starling mechanisms affect systolic LAS.

Accuracy of Bioelectrical Impedance Analysis in Estimation of Extracellular Space in Healthy Subjects and in Fluid Retention States

1994 ◽  
Vol 38 (3) ◽  
pp. 158-165 ◽  
Author(s):  
Giuseppe Sergi ◽  
Mauro Bussolotto ◽  
Paola Perini ◽  
Irene Calliari ◽  
Valter Giantin ◽  
...  
Keyword(s):  
Extracellular Space ◽  
Healthy Subjects ◽  
Bioelectrical Impedance Analysis ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Fluid Retention

Circadian Rhythm of Hydration in Healthy Subjects and Uremic Patients Studied by Bioelectrical Impedance Analysis

2007 ◽  
Vol 106 (3) ◽  
pp. p39-p44 ◽  
Author(s):  
Michele Buemi ◽  
Susanna Campo ◽  
Alessio Sturiale ◽  
Carmela Aloisi ◽  
Adolfo Romeo ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Healthy Subjects ◽  
Bioelectrical Impedance Analysis ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Uremic Patients

scholarly journals Leg pain in neuropathic postural tachycardia syndrome is associated with altered muscle membrane properties

2021 ◽  
Author(s):  
Belén Rodriguez ◽  
Karin Jost ◽  
Lotte Hardbo Larsen ◽  
Hatice Tankisi ◽  
Werner J. Z’Graggen
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Body Position ◽  
Lower Leg ◽  
Membrane Properties ◽  
Leg Pain ◽  
Muscle Membrane ◽  
Postural Tachycardia Syndrome ◽  
Postural Tachycardia ◽  
Muscle Excitability

Abstract Purpose In neuropathic postural tachycardia syndrome, peripheral sympathetic dysfunction leads to excessive venous blood pooling during orthostasis. Up to 84% of patients report leg pain and weakness in the upright position. To explore possible pathophysiological processes underlying these symptoms, the present study examined muscle excitability depending on body position in patients with neuropathic postural tachycardia syndrome and healthy subjects. Methods In ten patients with neuropathic postural tachycardia syndrome and ten healthy subjects, muscle excitability measurements were performed repeatedly: in the supine position, during 10 min of head-up tilt and during 6 min thereafter. Additionally, lower leg circumference was measured and subjective leg pain levels were assessed. Results In patients with neuropathic postural tachycardia syndrome, muscle excitability was increased in the supine position, decreased progressively during tilt, continued to decrease after being returned to the supine position, and did not completely recover to baseline values after 6 min of supine rest. The reduction in muscle excitability during tilt was paralleled by an increase in lower leg circumference as well as leg pain levels. No such changes were observed in healthy subjects. Conclusions This study provides evidence for the occurrence of orthostatic changes in muscle excitability in patients with neuropathic postural tachycardia syndrome and that these may be associated with inadequate perfusion of the lower extremities. Insufficient perfusion as a consequence of blood stasis may cause misery perfusion of the muscles, which could explain the occurrence of orthostatic leg pain in neuropathic postural tachycardia syndrome.

Human hydrometry: comparison of multifrequency bioelectrical impedance with2H2O and bromine dilution

1998 ◽  
Vol 85 (3) ◽  
pp. 1056-1062 ◽  
Author(s):  
Kenneth J. Ellis ◽  
William W. Wong
Keyword(s):  
Impedance Spectroscopy ◽  
Traditional Method ◽  
Healthy Subjects ◽  
Bioelectrical Impedance ◽  
Extracellular Water ◽  
Males And Females ◽  
The Mean ◽  
Total Body ◽  
Mean Differences ◽  
Age Range

The traditional method of assessing total body water (TBW), extracellular water (ECW), and intracellular water (ICW) has been the use of isotopes, on the basis of the dilution principle. Although the development of bioelectrical impedance techniques has eliminated many of the measurement constraints associated with the dilution methods, the degree of interchangeability between the two methods remains uncertain. We used multifrequency bioelectrical impedance spectroscopy (BIS),2H2O dilution, and bromine dilution to assess TBW, ECW, and ICW in 469 healthy subjects (248 males, 221 females) aged 3–29 yr. We found that the TBW, ECW, and ICW estimates for the BIS and dilution methods were significantly correlated ( r 2 = 0.80–0.96, P < 0.0001, SE of the estimate = 2.3–2.7 liters). On the basis of population, the constants used in the BIS analysis could be adjusted so that the mean differences with the dilution methods would become zero. The SD values for the mean differences between the dilution and BIS methods, however, remained significant for both males and females: TBW (±2.1–2.8 liters), ECW (±1.4–1.6 liters), and ICW (2.0–3.1 liters). To improve the accuracy of the BIS measurement for an individual within the age range we have examined, further refinement of the constants used in the BIS analysis is needed.

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