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Journal of Clinical Sleep Medicine :... May 2021Restless legs syndrome (RLS) is known to be a risk factor for cardiovascular disease. However, there are no electrophysiological biomarkers to assess this risk. This...
STUDY OBJECTIVES
Restless legs syndrome (RLS) is known to be a risk factor for cardiovascular disease. However, there are no electrophysiological biomarkers to assess this risk. This study aimed to evaluate heart rate variability (HRV) and cardiovascular reflexes in the supine and standing positions during wakefulness in patients with RLS.
METHODS
Fourteen drug-naïve patients with RLS (12 women and 2 men, mean age, 42.14 ± 7.81 years) and 10 healthy control patients underwent tests for blood pressure, heart rate when in the supine and standing positions, and deep breathing and handgrip tests in controlled laboratory conditions. Data on 5-minute R-R intervals at each position were collected and analyzed for HRV.
RESULTS
Expected cardiovascular reflexes were within the normal range and were similar between the 2 groups. In HRV analysis, the normalized unit of the low-frequency component and the low-frequency/high-frequency ratio during standing were lower in patients with RLS than in the control patients. The low-frequency/high-frequency ratio responses during the change from the supine to the standing position were significantly reduced in patients with RLS (mean ± standard deviation, 2.94 ± 3.11; control patients: 7.51 ± 5.58; P = .042.) On Spearman rank correlation, questionnaires related to sleep problems were associated with the parameters of HRV.
CONCLUSIONS
Patients with RLS showed reduced sympatho-vagal responses during the change from the supine to the upright position during wakefulness, and RLS-related sleep disturbance was a contributing factor for autonomic nervous system dysfunction. This case-control study showed a difference in HRV response to position change in a considerably small group of patients with RLS. The relevance of this finding is uncertain, but it may be worthy of further investigation in longitudinal studies on RLS and cardiovascular disease.
Topics: Adult; Case-Control Studies; Female; Hand Strength; Humans; Male; Middle Aged; Pharmaceutical Preparations; Restless Legs Syndrome; Standing Position
PubMed: 33438574
DOI: 10.5664/jcsm.9074 -
Clinical Nutrition ESPEN Oct 2021Bioelectrical impedance analysis (BIA) could be facilitated in subjects who are able to stand by using scales without (BIA) or with a retractable handle (BIA), provided... (Observational Study)
Observational Study
BACKGROUND & AIMS
Bioelectrical impedance analysis (BIA) could be facilitated in subjects who are able to stand by using scales without (BIA) or with a retractable handle (BIA), provided that they are as precise as BIA devices commonly used in the supine position in the hospital setting (BIA). This observational prospective cross-sectional study aimed to compare the precision and accuracy of BIA, BIA and BIA in a Caucasian population.
METHODS
Fat mass percentage (FM%) was measured in 160 healthy Caucasian subjects (80 men/80 women) aged 20-60 years, with a body mass index (BMI) ≥18.5 and < 30 kg/m, using the HAGRID Body Fat Scales (Huawei Technologies Co., Ltd., China) in BIA or BIA mode, and the Nutriguard-M (Data Input GmbH, Germany) as BIA. Intra-unit and inter-unit precisions of each device were evaluated by calculating the coefficients of variation (CV%) of 3 measurements with 3 different units of each device. Inter-device precisions were evaluated with Pearson correlations, Bland-Altman plots, and repeated measures ANOVA followed by post-hoc Bonferroni tests. Accuracy of these BIA devices was estimated in a subgroup of 16 subjects, using comparison with dual-energy X-ray absorptiometry (DXA).
RESULTS
The study population was 40 ± 12 years old, with a body height and weight of 171 ± 10 cm and 72.2 ± 11.5 Kg, respectively. All three devices were very precise with intra-unit CV% of 0.5%, 0.9%, and 0.3% and inter-unit CV% of 0.5%, 1.1%, and 0.4% for BIA, BIA and BIA, respectively. Inter-device precision was ±2.1% for BIA/BIA, ±1.9% for BIA/BIA, and ±1.3% for BIA/BIA. Bland-Altman plots showed bias ±1.96 SD of 0.3 ± 5.2% for BIA/BIA, -0.4 ± 4.5% for BIA/BIA and -0.6 ± 3.1% for BIA/BIA. Compared to DXA, all three devices tended to underestimate FM% in men with low BMI, while only BIA and BIA tended to overestimate FM% in women with high BMI. FM% measurement accuracy was ±2.6% for BIA/DXA, ±3.3% for BIA/DXA, and ±3.4% for BIA/DXA.
CONCLUSIONS
Both BIA and BIA show a good intra- and inter-unit precision close to BIA, making them suitable for rapid body composition assessment in non-bedridden subjects. However, all these three devices should not be used interchangeably, because BIA and BIA tend to accentuate FM% changes during body composition monitoring compared to BIA and DXA.
TRIAL REGISTRATION
ClinicalTrial.gov no. NCT04504799.
Topics: Absorptiometry, Photon; Adult; Body Composition; Cross-Sectional Studies; Electric Impedance; Female; Humans; Male; Middle Aged; Prospective Studies; Standing Position
PubMed: 34620328
DOI: 10.1016/j.clnesp.2021.08.010 -
International Orthopaedics Aug 2022Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS...
PURPOSE
Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS fusion, to detect adaptation mechanisms around fused spinal segments.
METHODS
Sixteen patients aged 53.9 ± 15.9 who underwent LS fusion between L3 and S1 were extracted from the database of an ongoing prospective study. Different spino-pelvic parameters were evaluated on full spine X-rays, standing, then sitting straight. Parameters were compared pre-operative versus post-operative, and on standing versus sitting X-rays.
RESULTS
Preliminary results revealed a significantly greater pre-operative pelvic tilt (PT) in sitting than standing posture, (p = 0.020) but not in post-operative (p = 0.087). After surgery, PT was lower in sitting compared to pre-operative (p = 0.034) but not in standing (p = 0.245). L4-S1 lordosis was lower in sitting than standing in pre-operative (p = 0.014) and post-operative (p = 0.021). Surgery decreased segmental lordosis above the fusion (PSL, proximal sagittal lordosis) in sitting (p = 0.039) but not in standing (p = 0.193). No significant differences in thoracic kyphosis (TK) were observed. Fusions down to L5 versus S1 showed no significant differences for PT and PSL, neither in sitting versus standing, nor pre-operative versus post-operative.
CONCLUSION
Before fusion, compared to standing, PT increases in sitting straight posture (pelvic retroversion), and the lumbar spine adapts by decreasing its lordosis, mainly at L4-S1. After fusion, the segments adjacent to the instrumented section, adapt in flexion at lumbosacral and thoracolumbar junctions, i.e. just below and above (PSL). This might have mechanical implications for the occurrence of adjacent segment disease.
Topics: Humans; Lordosis; Lumbar Vertebrae; Pilot Projects; Prospective Studies; Retrospective Studies; Sitting Position; Spinal Fusion; Standing Position
PubMed: 35266032
DOI: 10.1007/s00264-022-05365-6 -
Medicine and Science in Sports and... Jul 2021This study aimed to evaluate the effects of sit-to-stand and treadmill desks on sedentary behavior during a 12-month, cluster-randomized multicomponent intervention with... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
This study aimed to evaluate the effects of sit-to-stand and treadmill desks on sedentary behavior during a 12-month, cluster-randomized multicomponent intervention with an intent-to-treat design in overweight office workers.
METHODS
Sixty-six office workers were cluster-randomized into a control (n = 21; 8 clusters), sit-to-stand desk (n = 23; 9 clusters), or treadmill desk (n = 22; 7 clusters) group. Participants wore an activPAL™ accelerometer for 7 d at baseline, month 3, month 6, and month 12 and received periodic feedback on their physical behaviors. The primary outcome was total daily sedentary time. Exploratory outcomes included total daily and workplace sedentary, standing and stepping time, and the number of total daily and workplace sedentary, standing, and stepping bouts. Intervention effects were analyzed using random-intercept mixed linear models accounting for repeated measures and clustering effects.
RESULTS
Total daily sedentary time did not significantly differ between or within groups after 12 months. Month 3 gains were observed in total daily and workplace standing time in both intervention groups (sit-to-stand desk: mean Δ ± SD, 1.03 ± 1.9 h·d-1 and 1.10 ± 1.87 h at work; treadmill desk: mean Δ ± SD, 1.23 ± 2.25 h·d-1 and 1.44 ± 2.54 h at work). At month 3, the treadmill desk users stepped more at the workplace than the control group (mean Δ ± SD, 0.69 ± 0.87 h). Month 6 gains in total daily stepping were observed within the sit-to-stand desk group (mean Δ ± SD, 0.82 ± 1.62 h·d-1), and month 3 gains in stepping at the workplace were observed for the treadmill desk group (mean Δ ± SD, 0.77 ± 0.83 h). These trends were sustained through month 12 in only the sit-to-stand desk group.
CONCLUSIONS
Active-workstation interventions may cause short-term improvements in daily standing and stepping. Treadmill desk users engaged in fewer sedentary bouts, but sit-to-stand desks resulted in more frequent transitions to upright physical behaviors.
Topics: Accelerometry; Adult; Equipment Design; Female; Humans; Interior Design and Furnishings; Male; Middle Aged; Obesity; Occupational Health; Sedentary Behavior; Standing Position; Time Factors; Walking; Workplace; Young Adult
PubMed: 33449603
DOI: 10.1249/MSS.0000000000002594 -
BMC Public Health Jun 2020Gendered patterns of physical activity behaviours may help explaining health inequalities between men and women. However, evidence on such patterns in the working... (Comparative Study)
Comparative Study
BACKGROUND
Gendered patterns of physical activity behaviours may help explaining health inequalities between men and women. However, evidence on such patterns in the working population is sparse. This study aimed at documenting and comparing compositions of sitting, standing and moving at work and during leisure among male and female office workers of different age.
METHODS
Sitting (including lying), standing and moving were measured using accelerometry for, on average, four working days in 55 male and 57 female Swedish office workers. Behaviours were described in terms of time spent in four exhaustive categories: sitting in short (< 30 min) and long (≥30 min) bouts, standing, and moving. In a compositional data analysis approach, isometric log-ratios (ilr) were calculated for time sitting relative to non-sitting, time in short relative to long sitting bouts, and time in standing relative to moving. Differences between genders (men vs. women), domains (work vs. leisure), and according to age were examined for each ilr using ANOVA.
RESULTS
At work, time spent sitting in short bouts, sitting in long bouts, standing, and moving was, on average, 29, 43, 21 and 7% among men, and 28, 38, 26 and 7% among women. Corresponding proportions during leisure were 34, 27, 27 and 13% among men and 28, 27, 32 and 13% among women. Men spent more time sitting relative to non-sitting ([Formula: see text] =0.04, p = 0.03) than women, and less time standing relative to moving ([Formula: see text] =0.07, p = 0.01). At work compared to during leisure, both genders spent more time sitting relative to non-sitting ([Formula: see text] =0.47, p < 0.01); within sitting more time was spent in long relative to short sitting bouts ([Formula: see text] =0.26, p < 0.01), and within non-sitting, more time was spent standing than moving ([Formula: see text] =0.12, p < 0.01). Older workers spent less of their non-sitting time moving than younger workers ([Formula: see text] =0.07, p = 0.01).
CONCLUSION
Male office workers spent more time sitting relative to non-sitting than female workers, and more time moving relative to standing. Both genders were sitting more at work than during leisure. Older workers moved less than younger. These workers could likely benefit from interventions to reduce or break up prolonged sitting time, preferably by moving more.
Topics: Accelerometry; Adult; Age Factors; Data Analysis; Exercise; Female; Humans; Leisure Activities; Male; Middle Aged; Sex Factors; Sitting Position; Standing Position; Sweden; Women, Working; Workplace
PubMed: 32487107
DOI: 10.1186/s12889-020-08909-w -
Journal of Sports Science & Medicine Jun 2022Easy-to-use and accurate heart rate variability (HRV) assessments are essential in athletes' follow-up, but artifacts may lead to erroneous analysis. Artifact detection...
Easy-to-use and accurate heart rate variability (HRV) assessments are essential in athletes' follow-up, but artifacts may lead to erroneous analysis. Artifact detection and correction are the purpose of extensive literature and implemented in dedicated analysis programs. However, the effects of number and/or magnitude of artifacts on various time- or frequency-domain parameters remain unclear. The purpose of this study was to assess the effects of artifacts on HRV parameters. Root mean square of the successive differences (RMSSD), standard deviation of the normal to normal inter beat intervals (SDNN), power in the low- (LF) and high-frequency band (HF) were computed from two 4-min RR recordings in 178 participants in both supine and standing positions, respectively. RRs were modified by (1) randomly adding or subtracting 10, 30, 50 or 100 ms to the successive RRs; (2) a single artifact was manually inserted; (3) artifacts were automatically corrected from signal naturally containing artifacts. Finally, RR recordings were analyzed before and after automatic detection-correction of artifacts. Modifying each RR by 10, 30, 50 and 100 ms randomly did not significantly change HRV parameters (range -6%, +6%, supine). In contrast, by adding a single artifact, RMSSD increased by 413% and 269%, SDNN by 54% and 47% in supine and standing positions, respectively. LF and HF changed only between -3% and +8% (supine and standing) in the artifact condition. When more than 0.9% of the signal contained artifacts, RMSSD was significantly biased, whilst when more than 1.4% of the signal contained artifacts LF and HF were significantly biased. RMSSD and SDNN were more sensitive to a single artifact than LF and HF. This indicates that, when using RMSSD only, a single artifact may induce erroneous interpretation of HRV. Therefore, we recommend using both time- and frequency-domain parameters to minimize the errors in the diagnoses of health status or fatigue in athletes.
Topics: Artifacts; Athletes; Heart Rate; Humans; Standing Position
PubMed: 35719238
DOI: 10.52082/jssm.2022.260 -
PloS One 2020It is widely accepted that canine breeds stand and move differently. The prevalence of various musculoskeletal disorders such as hip and elbow dysplasia is also...
It is widely accepted that canine breeds stand and move differently. The prevalence of various musculoskeletal disorders such as hip and elbow dysplasia is also different between breeds. German shepherd dog (GSD) and Labrador retriever dog (LRD) are two large breeds with different conformations that have high prevalence of these disorders. This study quantifies the movement and standing posture of twelve healthy GSDs and twelve healthy LRDs to identify biomechanical similarities and differences that may be linked to sub-optimal hip and elbow mechanics. A pressure walkway and a motion capture system obtained measures of kinetics, kinematics and conformation during standing and trot. During standing, LRDs carry a greater percentage of the weight on the forelimbs (69%±5% vs. GSDs: 62%±2%, p<0.001) and their body Centre of Pressure (CoP) is located more cranially (p<0.001). GSDs had a greater pelvic tilt (79°±8 vs. 66°±9°, p = 0.004), more flexed stifles (44°±9° vs. LRDs: 34°±10°, p<0.05) and hocks (58°±11° vs. 26°±9°, p<0.01) and more extended hips (-10°±11° vs. 30°±12°, p<0.001). During trot, the GSDs' CoP had a longer anterior-posterior trajectory (151%±22% vs. LRDs: 93%±25% of the withers height, p<0.001). Stride parameters and loading of limbs were similar when normalised to the size and weight of the dog, respectively. The LRDs had a more extended thoracolumbar angle (p<0.001) and a less flexed lumbosacral angle (p<0.05). The LRDs' hip remained flexed during trot whereas the GSDs' hip joint was less flexed during swing (p<0.001) and more extended in late stance and early swing (p<0.001). In conclusion, the LRDs and GSDs differ in the way they stand and move and this would result in different loading pattern of the joints. Further investigation is required to determine the extent to which biomechanical differences are linked to musculoskeletal problems presented clinically.
Topics: Animals; Biomechanical Phenomena; Body Weight; Dogs; Female; Forelimb; Gait; Hip; Hip Dysplasia, Canine; Hip Joint; Joint Diseases; Male; Standing Position
PubMed: 33007006
DOI: 10.1371/journal.pone.0239832 -
Scientific Reports Nov 2022No clinical study has compared lung or lobe volumes on computed tomography (CT) between the supine and standing positions in patients with idiopathic lung fibrosis...
No clinical study has compared lung or lobe volumes on computed tomography (CT) between the supine and standing positions in patients with idiopathic lung fibrosis (IPF). This study aimed to compare lung and lobe volumes between the supine and standing positions and evaluate the correlations between the supine/standing lung volumes on CT and pulmonary function in patients with IPF. Twenty-three patients with IPF underwent a pulmonary function test and both low-dose conventional (supine position) and upright CT (standing position) during inspiration breath-holds. The volumes of the total lungs and lobes were larger in the standing than in the supine position in patients with IPF (all p < 0.05). Spearman's correlation coefficients between total lung volumes on chest CT in supine/standing positions and vital capacity (VC) or forced VC (FVC) were 0.61/0.79 or 0.64/0.80, respectively. CT-based volumes on upright CT were better correlated with VC and FVC than those on supine CT. Lung and lobe volumes in the standing position may be useful biomarkers to assess disease severity or therapeutic effect in patients with IPF.
Topics: Humans; Standing Position; Idiopathic Pulmonary Fibrosis; Respiratory Function Tests; Lung; Tomography, X-Ray Computed
PubMed: 36371537
DOI: 10.1038/s41598-022-24157-x -
Psychophysiology Aug 2021Our thoughts can influence sleep, but the underlying mechanisms are unknown. According to the theory of "embodied cognition," the semantic content of cognitive processes...
Our thoughts can influence sleep, but the underlying mechanisms are unknown. According to the theory of "embodied cognition," the semantic content of cognitive processes is represented by multimodal networks in the brain, which include body-related functions. Such multimodal representations could offer a mechanism, which explains mutual influences between cognition and sleep. Here we tested whether sleep-related words are represented in multimodal networks by examining the effect of congruent versus incongruent body positions on word processing during wakefulness. We experimentally manipulated the body position of 66 subjects (19-40 years old) between standing upright and lying down. Sleep- and activity-related words were presented around the individual speech recognition threshold. Our results show that word processing was facilitated in congruent body positions (sleep words: lying down and activity words: standing upright) compared with incongruent body positions, as indicated by a reduced N400 in the congruent condition with the lowest volume. In addition, early sensory components of the ERP (N180 and P280) were enhanced, suggesting that words were also acoustically better understood in a congruent body position. However, the difference in ERPs did not translate to differences on a behavioral level. Our results support the prediction of embodied processing of sleep- and activity-related words. Body position potentially induces a pre-activation of multimodal networks, thereby enhancing access to the semantic concepts of words related to current body position. The link between semantic meaning and body-related function could be a key element in explaining the influences of cognitive processing on sleep.
Topics: Adult; Electroencephalography; Evoked Potentials; Female; Humans; Male; Psycholinguistics; Sleep; Speech Perception; Standing Position; Supine Position; Young Adult
PubMed: 33942324
DOI: 10.1111/psyp.13824 -
Thermal, mechanical and electrical stimuli in antinociceptive studies in standing horses: an update.Veterinary Anaesthesia and Analgesia Jan 2020To perform a literature review of the thermal and mechanical antinociceptive devices used in pharmacological studies in standing horses published after 2011 (2012-2019).... (Review)
Review
OBJECTIVE
To perform a literature review of the thermal and mechanical antinociceptive devices used in pharmacological studies in standing horses published after 2011 (2012-2019). To complete a full literature review about electrical stimulation used for evaluation in similar studies.
DATABASES USED
PubMed, Google Scholar and Web of Science.
CONCLUSIONS
A high level of standardization has been reached in antinociceptive studies in standing horses using thermal and mechanical stimuli in most recent years. Commercially available testing devices to deliver thermal, mechanical and electrical stimuli, with observation of aversive responses to these stimuli, are reliable, sensitive and specific. For electrical stimulus testing, there is evidence that the resistance between the electrodes should be measured and should not exceed 3 kΩ to guarantee consistent and reproducible stimuli. The specific analysis of electromyographic activity after an electrical stimulus provides more detailed information about the neurons stimulated.
Topics: Analgesics; Animals; Electric Stimulation; Horses; Hot Temperature; Pain Measurement; Physical Stimulation; Standing Position
PubMed: 31813668
DOI: 10.1016/j.vaa.2019.09.003