UMIN-ICDS Clinical Trial

Public title

A study on cycling exercise performance and perceived fatigue after drinking hydrogen nanobubble water

Acronym

HNW-CYCLE Study

Scientific Title

An exploratory interventional study on the association between hydrogen nanobubble water intake and exercise performance indices during a cycling exercise task

Scientific Title:Acronym

HNW-CYCLE Trial

Region

Japan

Condition

Healthy adults (no specific disease targeted)

Classification by specialty

Rehabilitation medicine

Adult

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

To explore, in healthy adults, the association between hydrogen nanobubble water (HNW) intake and exercise performance indices (such as distance covered) and subjective burden during a 20-minute cycling exercise task, by comparing an HNW condition with an ordinary drinking water condition in a randomized crossover design. Participants are blinded to the allocated beverage condition (single blind). No invasive examinations such as blood sampling are performed.

Basic objectives2

Others

Basic objectives -Others

Exploratory investigation of the association between hydrogen nanobubble water intake and exercise performance indices and subjective burden during a cycling exercise task

Trial characteristics_1

Exploratory

Trial characteristics_2

Explanatory

Developmental phase

Not applicable

Primary outcomes

Distance covered (m) during the latter 10 minutes of the 20-minute cycling task, recorded from the cycle ergometer (POWER MAX V3 CONNECT) display at the end of exercise on each measurement day, and compared between the hydrogen nanobubble water condition and the ordinary drinking water condition.

Key secondary outcomes

1. Distance covered (m) over the entire 20-minute cycling task and during the first 10 minutes (at the end of exercise)
2. Mean pedaling cadence (rpm) and workload setting (kp) during exercise
3. Heart rate (bpm) at rest (before start), after the 5-minute warm-up, at 10 minutes into the main task, and immediately after the task
4. Percutaneous oxygen saturation (SpO2, %) at the same four time points
5. Rating of perceived exertion (Borg RPE, 6-20) at the same four time points and at the end of exercise
6. Blood pressure (mmHg) at rest before the start of measurement
7. Subjective symptoms questionnaire (Jikakusho shirabe; 25 items, 5-point scale): individual items and total score, before and after exercise
8. Fatigue site questionnaire (17 body regions, 4-point scale 0-3): individual regions and total score, before and after exercise
9. Body composition (body weight, body fat percentage, skeletal muscle mass, etc.; InBody270) at enrollment or on a measurement day, as background information
10. Occurrence and reason for discontinuation of exercise, and occurrence of adverse events or changes in physical condition, on each measurement day

Study type

Interventional

Basic design

Cross-over

Randomization

Randomized

Randomization unit

Individual

Blinding

Single blind -participants are blinded

Control

Placebo

Stratification

NO

Dynamic allocation

NO

Institution consideration

Institution is not considered as adjustment factor.

Blocking

YES

Concealment

Numbered container method

No. of arms

2

Purpose of intervention

Prevention

Type of intervention

Food

Interventions/Control_1

Hydrogen nanobubble water (HNW) condition: On the measurement day, participants ingest a total of 500 mL of hydrogen nanobubble water (Hydrogen NanoGAS Water, Symbiosis Co., Ltd.). Of this, 250 mL is ingested before the start of the cycling task, and the remaining 250 mL is ingested during the 5-minute warm-up and over the first 10 minutes of the 20-minute main cycling task. The beverage is dispensed into identical unlabeled containers identified only by container number, so that participants are not informed of the beverage condition on that measurement day. Volume, temperature, and container are matched to the ordinary drinking water condition. Time of ingestion, volume ingested, and any change in physical condition after ingestion are recorded. The intervention is a single-dose administration on one measurement day, with a 3-7 day interval between this condition and the ordinary drinking water condition.

Interventions/Control_2

Ordinary drinking water condition (control): On the measurement day, participants ingest a total of 500 mL of ordinary drinking water. Volume, timing, temperature, and container are identical to the HNW condition; the beverage is dispensed into identical unlabeled containers identified only by container number. Time of ingestion, volume ingested, and any change in physical condition after ingestion are recorded. The intervention is a single-dose administration on one measurement day, with a 3-7 day interval from the HNW condition.

Exercise task common to both conditions: Using a cycle ergometer (POWER MAX V3 CONNECT, Konami Sports Co., Ltd.), participants perform a 5-minute warm-up at a workload of 1 kp, followed by 20 minutes of cycling at a workload set in kp using body weight (kg) x 0.035 as a guide. Participants are instructed to continue exercising within the range they themselves judge sustainable for 20 minutes; forced continuation is not required. A 5-minute cool-down at low workload follows. Participants refrain from high-intensity exercise for 24-48 hours before measurement and from food intake for 3 hours before measurement; caffeine intake is also matched between conditions as far as possible.

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

65

years-old

>

Gender

Male and Female

Key inclusion criteria

Participants must meet all of the following
1. Students or faculty/staff enrolled at R Professional University of Rehabilitation
2. Aged 18 years or older and under 65 years
3. Able to understand the study and provide written informed consent of their own free will
4. Judged able to safely perform the cycling exercise task
5. Able to comply with the pre-measurement standardization (avoiding high-intensity exercise for 24-48 hours before measurement, fasting for 3 hours before measurement, etc.) and to attend two measurement sessions separated by 3-7 days

Key exclusion criteria

Participants meeting any of the following are excluded
1. Those judged unable to safely perform the cycling exercise task due to cardiovascular, respiratory, or orthopedic disease
2. Those judged, by self-report or prior confirmation, as possibly having symptoms aggravated by exercise
3. Those under exercise restriction by a physician
4. Those with poor physical condition on the measurement day (fever, marked fatigue, dizziness, nausea, chest discomfort, etc.)
5. Those with difficulty understanding the study procedures
6. Those judged by the principal investigator to be unsuitable for participation for any other reason

Target sample size

30

Name of lead principal investigator

1st name	Sechang
Middle name
Last name	Oh

Organization

R Professional University of Rehabilitation

Division name

Department of Physical Therapy, Faculty of Rehabilitation

Zip code

300-0032

Address

2-10-35 Kohoku, Tsuchiura, Ibaraki 300-0032, Japan

TEL

029-824-7611

Email

o-sechan@u.a-ru.ac.jp

Name of contact person

1st name	Sechang
Middle name
Last name	Oh

Organization

R Professional University of Rehabilitation

Division name

Department of Physical Therapy, Faculty of Rehabilitation

Zip code

300-0032

Address

2-10-35 Kohoku, Tsuchiura, Ibaraki 300-0032, Japan

TEL

029-824-7611

Homepage URL

Email

o-sechan@u.a-ru.ac.jp

Institute

R Professional University Of Rehabilitation

Institute

Department

Personal name

Organization

R Professional University Of Rehabilitation

Organization

Division

Category of Funding Organization

Self funding

Nationality of Funding Organization

Japan

Co-sponsor

Name of secondary funder(s)

KAKENHI, Grant-in-Aid for Scientific Research (C)); R Professional University Of Rehabilitation, institutional research funds; Oriental Shiraishi Corporation, scholarship donation

Organization

Research Ethics Review Committee, R Professional University Of Rehabilitation

Address

2-10-35 Kohoku, Tsuchiura, Ibaraki 300-0032, Japan

Tel

029-824-7611

Email

k-rinri@a-ru.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

アール医療専門職大学（茨城県）

Date of disclosure of the study information

2026

Year

07

Month

28

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

Individual participant data will not be made publicly available.

IPD sharing Plan description

Individual participant data collected in this study will be managed within the scope of the research protocol and the informed consent obtained from participants, and there is no plan for public release. Data are coded so that individuals cannot be identified, managed by the principal investigator, and retained for 10 years after the end of the study period. Results will be published only in statistically aggregated form. Inquiries for academic purposes will be considered individually by the principal investigator and, where necessary, addressed after approval by the research ethics review committee.

Recruitment status

Preinitiation

Date of protocol fixation

2026

Year

06

Month

10

Day

Date of IRB

2026

Year

07

Month

07

Day

Anticipated trial start date

2026

Year

07

Month

28

Day

Last follow-up date

2027

Year

03

Month

31

Day

Date of closure to data entry

2027

Year

04

Month

30

Day

Date trial data considered complete

2027

Year

05

Month

31

Day

Date analysis concluded

2027

Year

07

Month

31

Day

Other related information

This study was planned based on a preliminary examination of 11 participants conducted at our institution. In that examination, the distance covered during the latter 10 minutes of the cycling task was compared between the ordinary drinking water condition and the hydrogen nanobubble water condition, yielding an effect size of Cohen's dz = 1.00. Because this was a small preliminary examination and the effect size may have been overestimated, a more conservative dz = 0.55 was used for sample size calculation in the present study.

The order of conditions is randomly allocated using a randomization list generated with random numbers by an allocation manager who is not involved in the measurements, so that the number of participants in each order sequence is balanced. Beverages are dispensed into identical unlabeled containers identified only by container number, so that participants are not informed of the beverage condition on that measurement day.

No invasive examinations such as blood sampling are performed in this study. The study is conducted with the approval of the Research Ethics Review Committee of R Professional University Of Rehabilitation.

Registered date

2026

Year

07

Month

27

Day

Last modified on

2026

Year

07

Month

27

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000071359