Time-of-day influences postural balance in older adults

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• 作者：M.G. Jorgensen^a ; ^e ; ^{martin.joergensen@rn.dk} ; M.S. Rathleff^b ; U. Laessoe^c ; ^f ; P. Caserotti^d ; ^e ; O.B.F. Nielsen^a ; P. Aagaard^e
• 关键词：Postural balance ; Time-of-day ; Circadian rhythm ; Aging ; Force plate analysis ; Center of pressure
• 刊名：Gait and Posture
• 出版年：2012
• 期刊代码：106_09666362
• 类别：med
• 出版时间：April, 2012
• 卷：35
• 期：4
• 页码：653-657
• 文件大小：286 K

摘要

Background

Postural balance assessments are performed in both clinical and basic research settings on a daily basis. During a 24-h time span our physiology and physical performance undergo radical changes as we are influenced by the circadian rhythm. The time-of-day interaction on postural balance is unknown in older adults. The aim of this study was to investigate the time-of-day effect on postural balance in older adults.

Methods

Center of pressure (CoP) excursion was measured (100 Hz) by force plate analysis in 34 older adults during 30 s of narrow quiet bilateral stance. Measurements were performed around 9 a.m., 12.30 p.m. and 4 p.m. on the same day. Postural balance was quantified by velocity-moment, confidence ellipse area, total sway area and total sway length.

Results

An overall significant time-of-day (between 9 a.m. and 4 p.m.) effect was observed for velocity-moment (mm²/s) 57 卤 27-65 卤 29 (p = 0.001), confidence ellipse area (mm²) 36 卤 16-44 卤 19 (p < 0.001), total sway area (mm²) 548 卤 263-627 卤 285 (p = 0.001) and total sway length (mm) 373 卤 120-379 卤 113 (p = 0.037). The variation of postural balance was mostly pronounced from midday (12.30 p.m.) toward the afternoon (4 p.m.) in all sway parameters. Specifically between 12.30 p.m. and 4 p.m. confidence ellipse area increased by 18.5%, total sway area by 17.1%, velocity-moment by 15.8%and total sway length by 4.6%. No differences were observed between 9 a.m. and 12.30 p.m. in any of the sway parameters.

Conclusions

This study demonstrates that time-of-day influences postural balance in older adults. These findings have important scientific and clinical relevance, as they imply that time-of-day should be a controlled factor when assessing postural balance in older adults.