Effects of a cyborg-type robot suit HAL on cardiopulmonary burden during exercise in normal subjects
The hybrid assistive limb (HAL) is the world’s first cyborg-type robot suit that provides motion assistance to physically challenged patients. HAL is expected to expand the possibilities of exercise therapy for severe cardiac patients who have difficulty in moving on their own legs. As a first step, we examined whether or not the motion assistance provided by HAL during exercise could effectively reduce the cardiopulmonary burden in healthy subjects.
A total of ten healthy male adults (35 ± 12 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer with or without assistance from HAL. The CPX protocol consisted of four 3-min stages performed in a continuous sequence: rest, 0 W, 40 W, and 80 W. The heart rate (HR), blood pressure, oxygen uptake (VO2), minute ventilation (VE), and gas exchange ratio (R) were monitored during the CPX.
At 0 W, the HR, VO2, and VE were significantly higher when HAL was used. At 80 W, however, the HR (107 ± 14 vs 114 ± 14 beats/min, p < 0.01), systolic blood pressure (141 ± 15 vs 155 ± 20 mmHg, p < 0.01), VO2 (17.6 ± 2.4 vs 19.0 ± 2.5 mL/min/kg, p < 0.05), and R (0.88 ± 0.04 vs 0.95 ± 0.09, p < 0.05) were significantly lower when HAL was used.
HAL has the potential to reduce cardiopulmonary burden during moderate-intensity exercise and can, therefore, be used as a support for exercise therapy. Further studies on cardiac patients are expected to contribute to the establishment of a new exercise therapy program using HAL.
KeywordsHybrid assistive limb Exercise testing Cardiopulmonary burden
AK contributed to the conception or design of the work. YP, HW, TT, HK, MT, and HK contributed to the acquisition, analysis, or interpretation of data for the work. YP drafted the manuscript. AK critically revised the manuscript. JK, IN, AS, HK, KA, MI, and YS provided technical help with the design of the study. All gave final approval and agree to be accountable for all aspects of work ensuring integrity and accuracy.
This work was supported in part by a Grant-in-aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (Grant number JP17K09485).
Compliance with ethical standards
Conflict of interest
Hiroaki Kawamoto and Yoshiyuki Sankai are stockholders in, and the CEO of, Cyberdyne Inc. (Ibaraki, Japan), the manufacturer of the robot suit HAL. This study was proposed by the authors, and Cyberdyne was not directly involved in the study design, in the collection, analysis, and interpretation of data, in the writing of the report, or in the decision to submit the paper for publication.
Statement of human rights
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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