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Evidence-Based Complementary and Alternative Medicine
Volume 2012, Article ID 583016, 9 pages
Research Article

Local and Systemic Cardiovascular Effects from Monochromatic Infrared Therapy in Patients with Knee Osteoarthritis: A Double-Blind, Randomized, Placebo-Controlled Study

1Department of Physical Medicine and Rehabilitation, Shin Kong Wu Ho-Su Memorial Hospital, 95 Wen-Chang Road, Shih-Lin District, Taipei 111, Taiwan
2School of Medicine, College of Medicine, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan
3School of Nursing and Management in Gerontology, College of Nursing, Taipei Medical University, 250 Wuxing Street, Taipei 110, Taiwan
4Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, 17 Xuzhou Road, Taipei 100, Taiwan

Received 10 February 2012; Revised 27 April 2012; Accepted 27 April 2012

Academic Editor: Gerhard Litscher

Copyright © 2012 Ru-Lan Hsieh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Infrared (IR) therapy is used for pain relief in patients with knee osteoarthritis (OA). However, IR’s effects on the cardiovascular system remain uncertain. Therefore, we investigated the local and systemic cardiovascular effects of monochromatic IR therapy on patients with knee OA in a double-blind, randomized, placebo-controlled study. Seventy-one subjects with knee OA received one session of 40 min of active or placebo monochromatic IR treatment (with power output of 6.24 W, wavelength of 890 nm, power density of 34.7 mW/cm2 for 40 min, total energy of 41.6 J/cm2 per knee per session) over the knee joints. Heart rate, blood pressure, and knee arterial blood flow velocity were periodically assessed at the baseline, during, and after treatment. Data were analyzed by repeated-measure analysis of covariance. Compared to baseline, there were no statistically significant group x time interaction effects between the 2 groups for heart rate ( ), blood pressure (systolic blood pressure: ; diastolic blood pressure: ), or mean arterial blood flow velocity ( ) in follow-up assessments. The present study revealed that although there was no increase of knee arterial blood flow velocity, monochromatic IR therapy produced no detrimental systemic cardiovascular effects.