Impact of ao-dake-humi, Japanese traditional bamboo foot stimulator, on lower urinary tract symptoms, constipation and hypersensitivity to cold: a single-arm prospective pilot study
© The Author(s). 2016
Received: 12 November 2015
Accepted: 24 November 2016
Published: 9 December 2016
Ao-dake-humi is a traditional Japanese bamboo foot stimulator consisting of a half-pipe-shaped step made of bamboo used to stimulate the foot by stepping on it, and is commonly used to promote general health among the elderly in Japan. However, its efficacy has not been reported in the scientific literature. This study was performed to investigate the role of ao-dake-humi focusing on lower urinary tract symptoms (LUTS), constipation, and hypersensitivity to cold (HC).
Participants with LUTS, constipation, or HC were enrolled in this study. Ao-dake-humi was used twice a day for 28 days. Before and 28 days after starting ao-dake-humi use, international prostate symptom score (IPSS), quality-of-life (QoL) score, and overactive bladder symptom score (OABSS) were measured to evaluate the efficacy of ao-dake-humi on LUTS. To evaluate the objective efficacy of ao-dake-humi on LUTS, a frequency-volume chart (FVC) was plotted in LUTS patients for 3 days. A visual analogue scale (VAS) was used to evaluate the efficacy of ao-dake-humi on constipation (VAS-constipation) and HC (VAS-HC) in the participants with constipation or HC.
A total of 24 participants were enrolled in this study. Twenty-one participants had LUTS, 11 had constipation, and 17 participants had HC. IPSS, especially storage-subscore, QoL score and OABSS, decreased significantly after use of ao-dake-humi. The use of ao-dake-humi increased maximal bladder capacity, resulting in a significant decrease in urinary frequency as determined from the FVC. In accordance with the results of VAS-constipation and VAS-HC, both constipation and HC were significantly relieved after ao-dake-humi use.
The results of this prospective pilot study indicated that ao-dake-humi is safe and has therapeutic efficacy in cases of LUTS, constipation and HC. The possibility of using ao-dake-humi as physical neuromodulation therapy was shown in the management of LUTS, constipation and HC.
UMIN000019333 (UMIN-CTR, Registered October-15-2015) retrospectively registered.
Keywordsao-dake-humi Lower urinary tract symptoms Constipation Hypersensitivity to cold Urinary bladder Colon Skin Neuromodulation Reflexology
This study was conducted between July 2013 and October 2015. The trial registration number is UMIN000019333 (UMIN-CTR, registration date is 15th Oct. 2015).
Eligible participants were >20 y.o. with LUTS, constipation and/or HC. LUTS patients with IPSS >13 or dissatisfied with current LUTS treatments were enrolled. Constipation and HC were evaluated according to self-description. Exclusion criteria were as follows: patients who could not make the decision themselves, those with a custom of receiving foot massage, those incapable of walking by themselves, and those with a history of recurrent urinary tract infection or bladder stones. All of the LUTS patients had already received some medical care in a hospital or a private clinic. In the process of the previous management of LUTS before enrolling this trial, urinary tract infection and cancer including prostate cancer had already excluded. Subjects were also excluded if they received surgery, diagnosed malignant disease, and used other medical interventions, such as drugs, within the previous 3 months. Participants could continue to take medication for LUTS and constipation to maintain the same condition before and after the study. However, the participants were not permitted to start or stop any intervention for LUTS, constipation or HC during the study.
To evaluate the objective efficacy of ao-dake-humi on LUTS, a frequency-volume chart (FVC) was used. The FVC on 3 continuous days was recorded in all of the enrolled LUTS participants before and 28 days after starting ao-dake-humi use. The average total voided volume, daytime voided volume, nighttime voided volume, total urinary frequency in a day, daytime urinary frequency, and nighttime urinary frequency were evaluated for each day. The average mean voided volume, maximal voided volume, and minimal voided volume were also evaluated. Nighttime micturition was defined as micturition between 10:00 pm and 6:00 am.
All data are presented as the means ± SEM. The data were analysed using Excel-based statistical program file, Excel TouKei (Social Survey Research Information Co., Ltd., Tokyo, Japan), and p < 0.05 was considered to indicate significance. The changes before and after ao-dake-humi were analysed using the paired t test.
Results and discussion
65.2 ± 16.3
Body mass index (kg/m 2)
21.8 ± 2.2
Distribution of LUTS, constipation, and HC
LUTS and constipation
LUTS and HC
Constipation and HC
LUTS, constipation, and HC
Benign prostatic hyperplasia
Alpha 1-adrenocepter antagonist
Beta 3-adrenoceptor agonist
Differences in lower urinary tract symptoms, constipation and hypersensitivity to cold (HC) before and after ao-dake-humi use
LUTS (N = 21)
Constipation (N = 11)
HC (N = 17)
Objective values before and after ao-dake-humi based on frequency-volume-chart (FVC)
LUTS (N = 20)
Total urine volume (ml/day)
1684.7 ± 788.5
1669.1 ± 691.2
Mean voided volume (ml)
169.7 ± 52.8
187.0 ± 67.0
Maximal voided volume (ml)
331.5 ± 140.3
373.0 ± 139.0
Minimal voided volume (ml)
58.3 ± 31.4
72.8 ± 50.2
Total urinary frequency (/day)
10.9 ± 3.5
9.8 ± 2.7
Day-time urinary frequency (/6–22 o’clock)
8.9 ± 2.7
7.9 ± 1.7
Night-time urinary frequency (/22–6 o’clock)
2.0 ± 1.7
1.8 ± 1.6
Previous reports indicated that a decrease in environmental temperature induces numerous physiological responses, including increased urinary frequency in both humans and animals [10, 11]. Previously, we reported the relationship between HC and LUTS, and the efficacy of simultaneous approaches using Kampo-medicine . In this study, 60% of the enrolled participants had both LUTS and HC, and the efficacy of ao-dake-humi on HC was revealed subjectively. Moreover, constipation was also improved after ao-dake-humi use. Five of 11 participants with constipation had received drug treatment before starting this research. These results indicated that ao-dake-humi is a candidate therapeutic option to manage LUTS, constipation and HC. However, HC and constipation were evaluated on the basis of self-description using VAS. A further RCT with larger number of participants is needed.
Ao-dake-humi is a Japanese traditional home health appliance based on the theory of reflexology, and can be used at home to promote general health in daily use. Ao-dake-humi consists of a half-pipe-shaped foot-step made of bamboo cut into pieces 30–40 cm in length, and is widely used in Japan. The mechanisms of ao-dake-humi promoting general health are not yet known. However, neuromodulation and acupuncture may have similar mechanisms of action on LUTS, constipation and HC. Therefore, the effect of ao-dake-humi is thought not to be due to exercise but to stimulation of afferent nerves in the foot to modulate visceral organs, such as the urinary bladder and colon. Indeed, some neuromodulation equipment has been reported for treatment of LUTS, constipation and faecal incontinence . Electrical stimulation [13–18], magnetic stimulation [19–22] and interferential therapy [23, 24] are mainly used for modulation via the sacral nerve or tibial nerve. Although the precise mechanisms of neuromodulation are not yet known, activation of afferent nerves may lead to activation of efferent nerves in the pelvic organs, including the urinary bladder and colon [13, 14]. Physical stimulation, such as acupuncture, reflexology or foot massage, can be used as a source of neuromodulation via activation of sensory afferent pathways. In addition, the theory of reflexology, including acupuncture, can also be adapted for ao-dake-humi, and our hypothesis about ao-dake-humi is described on Fig. 1a also. In reflexology, areas of the foot are believed to correspond to the organs or structures of the body . Acupuncture was reported to have be effective for LUTS and constipation [26–30]. Moreover, in accordance with the foot chart of oriental foot massage, the urinary bladder and colon are located in the “hot spot” of ao-dake-humi stimulation (Fig. 1b). Of course, the exercise effect of ao-dake-humi cannot be completely excluded in this study. Therefore, an RCT should be done between step-work-exercise versus ao-dake-humi.
Ao-dake-humi has many advantages, such as its inexpensiveness, portability, and less risk of harm, compared to other interventions, including electrical neuromodulation. Ao-dake-humi costs about 5 dollars, and requires little maintenance. Moreover, as ao-dake-humi can be shared, it can be used in public spaces, such as hospitals and nursing homes. Ao-dake-humi is lightweight (almost 300 g), and is therefore easily portable, and ideal for daily use at home. Even in comparison with other similar treatments, including acupuncture and massage, ao-dake-humi has advantages. For example, the amount of stimulation can be controlled procedure-dependently in normal foot massage. In contrast, the amount of stimulation of ao-dake-humi is controlled according to bodyweight and of each patient. The average body mass index of the participants was 21.8 kg/m2, and obese participants were not included in this study. Although adequate methods should be proposed for participants with obesity in future studies, ao-dake-humi can standardise the amount of stimulation for patients. Adverse events associated with neuromodulation, such as infection, bleeding, pain, etc., have been reported [31, 32]. In this study, only three participants complained of slight pain due to ao-dake-humi use, and 98.5% of participants achieved use of ao-dake-humi according to a review of their diaries. All of the participants wished to continue ao-dake-humi use after this study. Even the participants that complained of slight pain at commencement of this study eventually felt comfortable with ao-dake-humi stimulation. There were no severe adverse events, such as diarrhea or urinary retention, among the participants. Of course, on theoretical grounds, it is impossible for the participants to have any severe advised events associated with use of ao-dake-humi. Compared with other neuromodulators, this is the unquestionable advantage of ao-dake-humi in management of LUTS and constipation.
However, this study had some limitations. In this pilot study, 2 sets/day of 2 min of ao-dake-humi were done for 28 days. There have been no reports regarding adequate use of ao-dake-humi. Time, duration, and frequency should be evaluated in future studies. The most important limitation of this study is bias because of its single-arm nature. Subjective results, such as IPSS and OABSS, should be interpreted carefully. However, objective results from FVC indicated that ao-dake-humi has efficacy for LUTS. Of course, objective evaluation should be performed even for constipation and HC, and more objective evaluation for LUTS, including uroflowmetry, residual urine volume, and cystometry, should also be performed in future studies. Lack of objective evaluation of constipation and HC is also a limitation of this study. However, object evaluation for constipation without any intervention is difficult, and object measurement of HC has not been established yet. Further investigation is needed to evaluate the exact role of ao-dake-humi on constipation and HC. However, even with these limitations, ao-dake-humi showed statistically relevant subjective and objective results in this study, and there were no adverse events. Thus, ao-dake-humi is a candidate of therapeutic option for LUTS, constipation and HC.
The results of this pilot study indicated that ao-dake-humi improved subjective symptoms of LUTS, constipation and HC. Ao-dake-humi also increased maximal voided volume leading to a reduction in urinary frequency without any severe adverse events.
Hypersensitivity to cold
International prostate symptom score
Lower urinary tract symptoms
Overactive bladder symptom score
Quality of life
Availability of data and materials
All of data generated or analysed during this study are included in this published article.
TM designed the study with OI, carried out the studies, participated in collecting data, performed the statistical analysis, and drafted the manuscript. TS, TD, HY, MI, SH, TN, and MN participated in acquisition of data. TO and OI supervised this trial. TM analysed the data; all authors revised the manuscript. All authors read and approved the final manuscript.
The authors of this paper have no financial or commercial interests to disclose.
Consent for publication
Ethics approval and consent to participate
All procedures were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. Written informed consent was obtained from all participants prior to inclusion in the study. The protocol of this study was approved by the ethics committee of Shinshu University School of Medicine (Permission No. 2184, 2012).
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