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Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes

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Background Muscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise. Methods Ten male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured. Results Although acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise. Conclusion Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.
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Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by
acute exercise in elite athletes
Medical Gas Research 2012, 2:12 doi:10.1186/2045-9912-2-12
Kosuke Aoki (aoiki@taiiku.tsukuba.ac.jp)
Atsunori Nakao (atsunorinakao@aol.com)
Takako Adachi (adachi@taiiku.tsukuba.ac.jp)
Yasushi Matsui (matsui@taiiku.tsukuba.ac.jp)
Shumpei Miyakawa (miyakawa@taiiku.tsukuba.ac.jp)
ISSN 2045-9912
Article type Research
Submission date 21 March 2012
Acceptance date 20 April 2012
Publication date 20 April 2012
Article URL http://www.medicalgasresearch.com/content/2/1/12
This peer-reviewed article was published immediately upon acceptance. It can be downloaded,
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Pilot study: Effects of drinking hydrogen-rich water
on muscle fatigue caused by acute exercise in elite
athletes
Kosuke Aoki1
Email: aoiki@taiiku.tsukuba.ac.jp
Atsunori Nakao2*
* Corresponding author
Email: atsunorinakao@aol.com
Takako Adachi1
Email: adachi@taiiku.tsukuba.ac.jp
Yasushi Matsui1
Email: matsui@taiiku.tsukuba.ac.jp
Shumpei Miyakawa1
Email: miyakawa@taiiku.tsukuba.ac.jp
1 Doctoral Program in Sports Medicine, Graduate School of Comprehensive
Human Sciences, University of Tsukuba, Ibaraki, Japan
2 Department of Emergency and Critical Care Medicine, Hyogo College of
Medicine, 1-1, Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
Abstract
Background
Muscle contraction during short intervals of intense exercise causes oxidative stress, which
can play a role in the development of overtraining symptoms, including increased fatigue,
resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can
function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on
oxidative stress and muscle fatigue in response to acute exercise.
Methods
Ten male soccer players aged 20.9±1.3 years old were subjected to exercise tests and blood
sampling. Each subject was examined twice in a crossover double-blind manner; they were
given either HW or placebo water (PW) for one week intervals. Subjects were requested to
use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by
measurement of peak torque and muscle activity throughout 100 repetitions of maximal
isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral
blood were sequentially measured.
Results
Although acute exercise resulted in an increase in blood lactate levels in the subjects given
PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak
torque of PW significantly decreased during maximal isokinetic knee extension, suggesting
muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no
significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease
after exercise.
Conclusion
Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and
improved exercise-induced decline of muscle function. Although further studies to elucidate
the exact mechanisms and the benefits are needed to be confirmed in larger series of studies,
these preliminary results may suggest that HW may be suitable hydration for athletes.
Introduction
Since energy demands and oxygen consumption increase during supermaximal exercise, such
as intermittent running, sprints, and jumps, production of reactive oxygen species (ROS) and
reactive nitrogen species (RNS) also increase, threatening to disturb redox balance and cause
oxidative stress. During normal conditions, ROS and RNS are generated at a low rate and
subsequently eliminated by the antioxidant systems. However, a greatly increased rate of
ROS production may exceed the capacity of the cellular defense system. Consequently,
substantial free radicals’ attack on cell membranes may lead to a loss of cell viability and to
cell necrosis and could initiate the skeletal muscle damage and inflammation caused by
exhaustive exercise [1-3]. Although well-trained athletes suffer from less oxidative stress
reduction because their antioxidant systems adapt, accumulation of intense exercise can
provoke an increase in oxidative stress [4]. To mitigate oxidative stress-induced adverse
events during sports, antioxidant supplementation among athletes has been well documented.
Although results of these studies are often contradictory depending on the antioxidant
compounds and quantity, some studies demonstrate the beneficial effects of antioxidants on
muscle fatigue or performance [5,6].
Recently, the beneficial effects of hydrogen-rich water (HW) have been described in
experimental and clinical disease conditions [7,8]. Although research on the health benefits of
HW is limited and there is scant data on long-term effects, pilot studies on humans suggest
that consuming HW may help prevent metabolic syndrome [9], diabetes mellitus [10], and
cancer patients’ side effects with radiotherapy [11]. Since hydrogen is known to scavenge
toxic ROS [12] and induce a number of antioxidant proteins [13,14], we hypothesized that
drinking HW may be beneficial for athletes in reducing oxidative stress-induced muscle
fatigue following acute exercise. In this study, we evaluated the efficacy of hydrogen-rich
water on healthy subjects by measuring muscle fatigue and blood lactate levels after exercise.
Although further studies are needed to elucidate the exact mechanisms and benefits, this
report suggests that hydrogen-rich water might be an appropriate hydration fluid for athletes.
Methods
Subjects
Ten male soccer players aged 20.9±1.3 years old were subjected to exercise tests and blood
sampling. None of the subjects were smokers or were taking any supplements/medicines.
Each subject provided written informed consent before participation in accordance with the
University of Tsukuba’s Human Research Ethics Committee. Physical characteristics of the
subjects are shown in Table 1. All the players were involved in daily training sessions except
the day of experiment.
Table 1 Subjects’ Physical Characteristics (n
=
10)
Variable Value
Age (year) 20.9
±
1.3
Height (cm) 172.0
±
3.8
Body weight (kg) 67.1
±
5.2
BMI (kg/m
2
) 22.8
±
1.4
VO
2
max (ml/kg/min) 53.2
±
4.9
BMI: body mass index, VO2max: maximal oxygen uptake
Generation of hydrogen-rich water
A plastic shelled product consisting of metallic magnesium (99.9 % pure) and natural stones
in polypropylene containers combined with ceramics (Doctor SUISOSUI®, Friendear,
Tokyo, Japan) was used to produce hydrogen. The product was capable of generating
hydrogen when placed in drinking water via the following chemical reaction:
Mg+2H2OMg (OH)2+H2. The magnesium stick or a placebo (a casting-only stick
without magnesium) was immersed in mineral water (Volvic®, Kirin Inc., Tokyo) for 24
hours prior to drinking. The final hydrogen concentrations of the placebo water (PW) and
hydrogen-rich water (HW) were 0 and 0.92~1.02 mM, respectively [9,11]. Each subject was
examined twice in a crossover double-blind manner, given either HW or PW for one week
intervals.
Dose and mode of administration of hydrogen-rich water
Subjects were provided with three 500 ml bottles of drinking water and instructed to place
two magnesium sticks in each bottle 24 hours prior to drinking. Participants were asked to
drink one bottle at 10:00 PM of the day before the test, one at 5:00 AM, and one at 6:20 AM
on the day of examination. In summary, subjects consumed 1,500 ml of HW or PW.
Protocol
The research protocol started at 6:00 AM. Subjects were given meals between 9:00 PM and
10:00 PM the day before experiments, and fasted overnight. No breakfast was given on the
day of the experiments. The subjects were first required to rest in a sitting position for 30
minutes. The exercise test consisted of the following: 1) Maximal progressive exercise test to
define maximal oxygen uptake (VO2max); 2) cycling an ergometer for 30 minutes at
approximately 75 % VO2max (Exercise-1); and 3) Running 100 maximal isokinetic knee
extensions at 90 °sec-1 (Exercise-2). Blood samples were collected from an antecubital vein
just before Exercise-1 (6:30 AM), immediately after Exercise-1 (7:15 AM), immediately after
Exercise-2 (7:30 AM), 30 minutes after Exercise-2 (8:00 AM) and 60 minutes after Exercise-
2 (8:30 AM).
Maximal progressive exercise test
First, to define maximal oxygen uptake (VO2max), the subjects were subjected to a maximal
progressive exercise test on a bicycle ergometer (232CL, Conbiwellness, Tokyo). The test
consisted of a continuous step test beginning at a 30 W load, and increasing by 20 W every
minute until exhaustion. The subjects were instructed to ride at 50 rpm/min. Pulmonary gas
exchange values were measured using an exhaled gas sensor (AE280S, Minato Medical®,
Osaka, Japan) via a breath-by-breath system, and the mean values were calculated every 30
seconds for analysis. We determined that VO2max was reached when the oxygen
consumption reached its plateau [15].
Fixed-load cycling at 75 % (high intensity) of VO2 max
Before the test started, the subjects rested for two minutes. After warming up at a load of
50 W for one minute, the subjects were instructed to ride at submaximal levels for 30
minutes. Pulmonary gas exchange values were monitored to maintain VO2max at
approximately 75 %. During the experiments, the subjects were frequently verbally instructed
to control the range of motion to maintain VO2max at approximately 75 %.
Maximal isokinetic knee extensions
A calibrated Biodex System 3 isokinetic device (Biodex Medical Systems, New York, USA)
was used to measure peak torque (PT) and knee-joint position throughout 100 repetitions of
maximal isokinetic knee extension. During testing, each subject was seated on the Biodex
system 3 with 90 ° hip flexion, and restraining straps were placed across the waist and chest
in addition to a rigid sternal stabilizer. The dynamometer was motor driven at a constant
velocity of 90 °/sec. Each subject performed a series of 100 isokinetic contractions using the
knee extensors of the right leg from 90 ° of flexion to 0 ° (full extension). As the arm of the
dynamometer moved up from 90 ° to 0 °, subjects were encouraged to perform maximally for
each contraction throughout the full range of motion. Subjects relaxed as the dynamometer
arm moved back to 90 °. Each contraction and relaxation period lasted one second and the
total length of the contraction cycle was thus two seconds. All subjects were able to complete
the full 100 contractions.
Measurement of muscle fatigue
To measure muscle fatigue, the widely used First Fourier transform technique (FFT) is
utilized to analyze mean frequency of surface electromyogram (EMG) [16]. EMG signals
were obtained from the rectus femoris muscle via electrodes connected to a 4-channel
frequency-modulation transmitter (Nihon Kohden, Tokyo, Japan). All data were stored and
analyzed using the FFT functions in Acknowledge 3.7.5 software (BIOPAC SYSTEM, Santa
Barbara, USA). Mean power frequency (MPF) and median power frequency (MDF) were
calculated as previously described [17]. MPF shift of the EMG signal toward lower
frequencies has been extensively used in static contractions to indicate the development of
peripheral fatigue.
Blood test
Blood lactate levels were determined using a commercially available Lactate Pro LT17170
kit (Arkray, Inc., Kyoto, Japan). The concentrations of derivatives of reactive oxidative
metabolites (dROMs) and biological antioxidant power (BAP) in the peripheral blood were
assessed using a Free Radical Analytical System (FRAS4; Wismerll, Tokyo, Japan).
Laboratory tests for creatine kinase (CK) were conducted using standardized procedures at
Kotobiken Medical Laboratory Services (Tokyo, Japan).
Statistical analysis
Repeated analysis of variance (ANOVA) tests were used to compare pre- and post-exercise
measurements. The F-test with Bonferroni post hoc group comparisons was performed where
appropriate. Probability values less than 0.05 were considered to be statistically significant.
SPSS 18.0 was used to perform the statistical analysis. Since the experiment was planned to
have a 90 % power of achieving significance at the 5 % level, the sample size in this model is
calculated to be between 8.91 and 9.25 (90 % power and 5 % significance level) in blood
lactate levels based on our previous experiences. Therefore, we assumed the sample size
would be appropriate for accumulation of preliminary data.
Results
Blood analysis for lactic acid, d-ROMs, BAP and CK
As shown in Table 2, blood d-ROMs levels increased after exercise in subjects in both groups
treated with PW and HW. However, there was no statistical difference between the groups.
Eventhough the blood lactate level were significantly increased in both HW and PW at 45
and 60 min after exercise, these levels were comparably and significantly lower in the HW
than in the PW group (Figure 1).
Table 2 Changes in Blood Levels
0 min 45 min 60 min 90 min 120 min
d-ROMs
(U.CARR) PW 269.0
±
50.8 285.7
±
52.3* 287.0
±
56.9* 274.2
±
50.2 280.0
±
47.6
HW 281.3
±
61.8 303.5
±
46.3* 308.6
±
56.1* 296.1
±
57.9 307.0
±
45.8
BAP
(µmol/L) PW 2347.3
±
155.8 2648.9
±
96.5* 2632.8
±
146.4* 2349.6
±
152.0 2321.8
±
196.9
HW 2336.7
±
123.1 2659.1
±
102.1* 2664.6
±
201.0* 2299.8
±
104.6 2356.4
±
143.7
CK (IU/L) PW 247.0
±
105.1 296.5
±
119.9* 300.9
±
127.7* 264.7
±
113.3* 256.3
±
111.7
HW 407.4
±
269.9 483.2
±
314.0* 478.1
±
314.5* 428.2
±
282.0 353.7
±
264.6
Data were shown as mean±standard deviation (SD). *p<0.05 vs 0 min
Figure 1 Sequential changes of blood lactate levels during exercise. Blood lactate levels in
the athletes given PW significantly increased immediately after exercise compared to the
levels at pre-exercise. HW significantly reduced blood lactate levels post exercise using
bicycle ergometer. (*p<0.05 vs. time 0. #p<0.05 vs PW, N=10)
Maximal knee extension exercise
At analysis for maximal knee extension exercise, we divided into five frames of 100-
repetition knee extension at the peak torque of isokinetic knee extension exercise [18]. Each
frame was corresponded to 20 repetitions; Frame 1 for the first 20 repetitions, Frame 2 for the
following 21-40 repetitions, Frame 3 for 41-60 repetitions, Frame 4 for 61-80 repetitions and
Frame 5 for the last 81-100 repetitions. Although the peak torque of subjects treated with PW
significantly decreased during the first 40 repetitions (Frame 1-2), the reduction of peak
torque in the subjects given HW did not reach statistical difference, suggesting that HW
inhibited the early decrease of peak torque of the subjects.
MDF and MPF from EMG analysis
MDF and MPF in the subjects treated with PW or HW significantly decreased with time
during exercise. While these values significantly decreased at Frame 1-2, there was no
statistical difference between the subjects receiving PW and those receiving HW (Figure 2 B,
C).
Figure 2 (A) Changes in Peak torque (PT) every 20 repetitions (rep
=
1 frame) during
100 maximum isokinetic knee extensions. PT of the subjects treated with PW significantly
decreased during the initial 40-60 contractions by approximately 20-25 % of the initial
values, followed by a phase with little change. On the other hand, there was no statistical
difference between Frame 1 and Frame 2 in HW, indicating that HW prevented the
decreasing the peak torque during the first 2 Frames. HW, Hydrogen rich water; PW, Placebo
water. (*p<0.05 vs Frame 1, N=10). (B) Changes in median frequency (MDF) every 20
repetitions (rep
=
1 Frame) during 100 maximum isokinetic knee extensions. Although
exercise significantly reduced MDF values during the first 2 Frames, there was no statistical
difference between HW and PW in all Frames. HW, Hydrogen rich water; PW, Placebo
water. (*p<0.05 vs Frame 1, N=10). (C) Changes in mean power frequency (MPF) every
20 repetitions (rep
=
1 Frame) during 100 maximum isokinetic knee extensions. There
was no statistical difference between HW and PW in all Frames. HW, Hydrogen rich water;
PW, Placebo water. (*p<0.05 vs Frame 1, N=10)
Discussion
In this preliminary study, we showed that hydration with HW attenuated increase of blood
lactate levels and prevented post-exercise decrease of peak torque, an indicator of muscle
fatigue. Muscle fatigue is caused by many different mechanisms, including the accumulation
of metabolites within muscle fibers and the generation of an inadequate motor command in
the motor cortex. The accumulations of potassium, lactate, and H+ have often been suggested
as being responsible for the decrease in muscle contractility [19]. In addition, aerobic,
anaerobic, or mixed exercise causes enhanced ROS production, resulting in inflammation and
cellular damage [20]. Short bursts of heavy exercise may induce oxidative stress through
various pathways such as electron leakage within mitochondria, auto-oxidation of the
catecholamine, NADPH activity, or ischemia/reperfusion [21]. Although the mechanism
involved in the efficacies of HW remains unclear, our results show that hydration with HW
could be feasible for acute exercise. Proper and adequate hydration is helpful for elite athletes
to achieve the best performance. HW can easily replace regular drinking water on a routine
basis and would potentially prevent adverse effects associated with heavy exercise.
Factors such as age, nutritional status, training level, and physical activity category can
influence the results [22,23]. Although we had anticipated that hydrogen, a known
antioxidant, would reduce oxidative stress following acute exercise, the effects of oral intake
of hydrogen rich water were marginal and did not affect the level of oxidative markers after
exercise. This can be explained by the facts that the athletes in our study have routinely
trained and their antioxidant defense systems may be more active. Previous studies reported
that repeated aerobic training increases antioxidant enzyme activity and subsequently
decreases oxidative stress [2,24-26]. Also, considering the short life-span of hydrogen in
circulation [27], more frequent drinking of HW during exercise might have additional effects.
In a future study, the efficacy of HW on untrained subjects or recreational exercisers, who
may have poorly established antioxidant systems to combat exercise-induced oxidative stress,
should be tested. Furthermore, different drinking protocols should be investigated.
We quantified muscle fatigue as a decline in the maximal force or power capacity of muscle,
which means that submaximal contractions can be sustained after the onset of muscle fatigue.
Similarly, blood lactate concentration is one of the most often measured parameters during
clinical exercise testing, as well as during performance testing of athletes. Lactate has often
been considered one of the major causes of both fatigue during exercise and post-exercise
muscle soreness. Lactate generated from the anaerobic breakdown of glycogen in the muscle
occurs only during short bouts of relatively high intensity exercise and it is usually related to
fatigue and muscle soreness. Previous evidence has shown that inorganic phosphate from
creatine phosphate was the main cause of muscle fatigue [28].
Dehydration in athletes may also lead to fatigue, poor performance, decreased coordination,
and muscle cramping. Although further investigations will be warranted, drinking HW may
be an appropriate hydration strategy [29]. In this study, we administered HW or PW to
subjects prior to exercise. Further investigation is required to determine the best timing, dose,
and hydrogen concentration of drinking water to optimize the effects of HW.
In conclusion, our preliminary data demonstrated that consumption of HW reduced blood
lactate levels and improved muscle fatigue after acute exercise. Although further studies are
absolutely warranted, drinking HW would be a novel and effective fluid hydration strategy
for athletes.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
KA, TA and YM participated in the protocol design and the data accumulation. AN
conceived the study and drafted the manuscript. SM participated in the study design and
coordination. All authors read and approved the final manuscript.
Acknowledgements
This research was supported by a Daimaru Research Foundation grant awarded to SM.
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0
2
4
lactate (mmol/L)
40 60 100 120
*
#
*
#
6
5
3
1
Time (minutes)
PW
HW
8020
Figure 1
... The medical application of molecular hydrogen in humans was originally documented approximately half a century ago and has since been evaluated in various clinical contexts [1,2]. In the past decade, the sports industry has utilized molecular hydrogen and other buffering agents to increase the body's antioxidant response and improve the efficiency of aerobic and anaerobic metabolism, anecdotally leading to improved athletic performance during high intensity exercise [2][3][4]. Enabled by its size, molecular hydrogen works through rapid diffusion into living tissues and cells [2]. The hydrogen (H2) molecule can penetrate through the cell membrane and the mitochondria where it helps to maintain a state between oxidation and reduction and maximize aerobic energy production [5]. ...
... The hydrogen (H2) molecule can penetrate through the cell membrane and the mitochondria where it helps to maintain a state between oxidation and reduction and maximize aerobic energy production [5]. Molecular hydrogen can be administered by different methods (inhalation of H2 gas or as injectable saline solutions, topical packs, or tablets), but one of the most common ways is the oral ingestion of hydrogen-rich water (HRW) [2,[4][5][6]. HRW has a pH higher than normal water and has become commercially available [7]. Recently, some studies have suggested it can improve athletic performance by reducing exercise-related metabolic acidosis and antioxidant and anti-inflammatory responses and delaying the onset of fatigue [7][8][9]. ...
... lactate), as well as, subject reported outcome measures identifying a reduction in fatigue (e.g. FI-fatigue index, fatigue assessment through VAS scores, RPE-ratings of perceived exertion) [2][3][4]9]. As a result of the cumulative properties of molecular hydrogen, an improvement in performance has been identified in some studies through an increase in power and torque (e.g. ...
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In the last decade, use of molecular hydrogen, through hydrogen-rich water (HRW), has become commonplace in the sports industry with anecdotal claims of improving athletic performance and endurance. Publications, clinical trials, and case studies have begun to emerge with the growing interest to clinically-validate the claims of improved performance and recovery in the athletic population. The objective of the current article is to review the recent literature to understand the effects of molecular hydrogen, through ingestion of hydrogen-rich water on muscles, joints, and athletic performance during the peri-exercise period. The following literature review documents the relevant effects identified within the included studies. A review of the studies published in the last ten years (2012-2022) pertaining to hydrogen-rich water (HRW) was performed. Using the PubMed search engine, the terms “hydrogen water” and “athlete” were searched. Quantitative data points pertaining to cardiorespiratory variables, blood markers, subject reported outcome measures, and athletic performance were identified from the included studies. Based on the aforementioned search criteria, one hundred and one articles were identified. Among these, fourteen studies pertained to the effects of molecular hydrogen during exercise. Of these studies, eleven studies reported the clinical findings associated with oral ingestion of liquid HRW and three studies identified observations pertaining to other hydrogen-rich applications in transdermal and tablet forms. The recent literature suggests that HRW may provide anti-inflammatory benefits as a neutralizing agent without evidence of side effects during high-intensity exercise in trained athletes. Consequently, when used during the peri-exercise period, HRW may be associated with anti-fatigue effects and improved athletic performance. The identified evidence supporting the use of HRW during the peri-exercise period is limited, and its extrapolation should be performed with caution. Despite the lack of significant high-quality evidence available in the recent literature, molecular hydrogen, through ingestion of HRW, has been adopted in the sports industry for its antioxidant, anti-inflammatory, and anti-fatigue properties identified in trained athletes, and it is used anecdotally to impact athletic performance without significant observed risk of side effects.
... Our previous studies demonstrated that H 2 attenuated the intensive exercise-induced elevation in oxidative damage or the reduction in antioxidant capacity in humans (Koyama et al., 2008;Dobashi et al., 2020;Shibayama et al., 2020) and thoroughbred horses (Yamazaki et al., 2015). Moreover, H 2 -rich water improved muscle fatigue (Aoki et al., 2012;Botek et al., 2021Botek et al., , 2022 and attenuated an increase in blood lactate concentrations during exercise (Drid et al., 2016;Botek et al., 2019Botek et al., , 2021Mikami et al., 2019), as well as inflammatory responses (Ara et al., 2018;Nogueira et al., 2018Nogueira et al., , 2021. Furthermore, a recent study reported that AEW ingestion improved energy expenditure during submaximal endurance cycling in a heated environment (Ito et al., 2020). ...
... As expected, the increase in blood lactate concentration during Running was attenuated by drinking the A-CE compared to the P-CE; nevertheless, no significant differences in HR, SpO 2 , and RPE were observed between the two trials throughout the experiments. This result is consistent with previous reports that the ingestion of H 2 -rich water attenuated the endurance exercise-induced elevation in blood lactate levels in men (Ostojic et al., 2011;Aoki et al., 2012;Botek et al., 2019;Mikami et al., 2019) and women (Drid et al., 2016). A clinical study demonstrated that H 2 -rich water decreased the lactate/pyruvate ratio in patients with mitochondrial myopathy, indicating that H 2 -rich water may improve mitochondrial function and oxidative metabolism (Ito et al., 2011). ...
... Our recent study reported that the ingestion of high concentrations of H 2 in saturated water (approximately 5.0 ppm) attenuated the reduction in systemic antioxidant capacity after three consecutive days of sprint cycling exercise . Moreover, H 2 concentrations of approximately 1.0 ppm improved muscular performance in a previous study (Aoki et al., 2012;Botek et al., 2021Botek et al., , 2022. Since there is no clearly defined dose-response curve of H 2 to induce physiological changes (Ostojic, 2015), it is uncertain whether an H 2 concentration of 0.3 ppm is enough to improve various exercise performances and redox responses. ...
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Purpose This study investigated the effects of 1400 mL intake of alkaline electrolyzed water (AEW) or purified water (PW) into which carbohydrate-electrolyte (CE) was dissolved on improving physiological responses during exercise under heat stress. Methods This double-blinded, crossover randomized controlled trial included 10 male participants who completed two exercise trials in a hot environment (35 °C, ambient temperature, and 50% relative humidity) after consuming CE-dissolved PW (P-CE) or CE-dissolved AEW (A-CE). The exercise trial consisted of running for 30 minutes on a treadmill (at an intensity corresponding to 65% of heart rate reserve adjusted for heat stress conditions) and repeated sprint cycling (10 × 7-s maximal sprint cycling), with a 35-min rest interval between the two exercises, followed by a 30-min post-exercise recovery period. Before and after running, and after cycling, the participants drank P-CE (hydrogen concentration of 0 ppm, pH 3.8) or A-CE (0.3 ppm, pH 4.1). Blood samples were obtained before, during (rest interval between running and cycling), and post-exercise. Results Repeated sprint performance and oxidative stress response did not differ between the P-CE and A-CE trials. A-CE consumption significantly attenuated the increase in blood lactate concentration during the running exercise but not during repeated sprint cycling under heat stress conditions. Conclusion Our findings suggested that A-CE did not significantly affect repeated sprint performance; however, the attenuated elevation in blood lactate by A-CE ingestion implies a partial enhancement of endurance performance during submaximal exercise under heat stress.
... The administration of H 2 to mice, rats, and racehorses subjected to acute or chronic exercise stress was found to exert anti-fatigue effects (46)(47)(48)(49). Similar findings were obtained in healthy subjects who drank hydrogen-rich water (HRW) or inhaled H 2 gas before or after exercise (50)(51)(52)(53)(54)(55)(56)(57). The efficacy of HRW in patients with ME/CFS was suggested by Morris et al. (58) and Lucas et al. in their reviews (59). ...
... H 2 exerted anti-fatigue effects in mice, rats, and racehorses subjected to acute or chronic exercise loading (46)(47)(48)(49). Similarly, the anti-fatigue effects of H 2 on healthy subjects who performed acute or chronic exercise have been investigated (50)(51)(52)(53)(54)(55)(56)(57). In this chapter, we provide an overview of the specific anti-fatigue effects of H 2 in animal models and human clinical trials, and also discuss the underlying mechanisms ( Table 1). ...
... Intense exercise for a short period of time may induce oxidative stress, which may, in turn, contribute to the development of overtraining symptoms, such as increased fatigue, resulting in muscle microdamage and inflammation. Aoki et al. investigated the effects of HRW on oxidative stress and muscle fatigue during acute exercise (50). Athletes ingested HRW (2.0 ppm) or PW, followed by exercise loading with a cycle ergometer and maximal isometric knee extension. ...
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Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disorder that is characterized by fatigue that persists for more than 6 months, weakness, sleep disturbances, and cognitive dysfunction. There are multiple possible etiologies for ME/CFS, among which mitochondrial dysfunction plays a major role in abnormal energy metabolism. The potential of many substances for the treatment of ME/CFS has been examined; however, satisfactory outcomes have not yet been achieved. The development of new substances for curative, not symptomatic, treatments is desired. Molecular hydrogen (H2) ameliorates mitochondrial dysfunction by scavenging hydroxyl radicals, the most potent oxidant among reactive oxygen species. Animal experiments and clinical trials reported that H2 exerted ameliorative effects on acute and chronic fatigue. Therefore, we conducted a literature review on the mechanism by which H2 improves acute and chronic fatigue in animals and healthy people and showed that the attenuation of mitochondrial dysfunction by H2 may be involved in the ameliorative effects. Although further clinical trials are needed to determine the efficacy and mechanism of H2 gas in ME/CFS, our literature review suggested that H2 gas may be an effective medical gas for the treatment of ME/CFS.
... In a double-blinded, placebo-controlled study, 4 weeks administration of hydrogenrich water (HRW) helped reduce and prevent accumulated oxidative stress in the brain, thereby improving mood, anxiety, and autonomic function in adult volunteers (Mizuno et al., 2017). Recently, several studies have arisen to explore the potential anti-fatigue effects of H 2 (Table 1) in healthy cohorts who performed either acute or chronic exercise, and shown the promise of intaking H 2 either before or after the exercise may help alleviate fatigue (Aoki et al., 2012;Da Ponte et al., 2018;Botek et al., 2019;LeBaron et al., 2019;Mikami et al., 2019;Dobashi et al., 2020;Hori et al., 2020;Shibayama et al., 2020;Timon Andrada et al., 2020;Dong et al., 2022). For example, intaking HRW before exercise has been shown to improve exercise-induced decline of muscle function (Aoki et al., 2012), and thus alleviate fatigue (Pantovic et al., 2016); and the inhalation of hydrogen-rich gas mixture after exercise can help attenuated the reduction in athletic performance (e.g., the Abbreviations: H 2 = molecular hydrogen; HRW, hydrogen-rich water; PPO, peak power output; RR, respiratory rate; HR, heart rate; RPE, ratings of perceived exertion; BAP, biological antioxidant potential; d-ROM, diacron-reactive oxygen metabolites; HG, hydrogen-rich gas mixture; 8-OHdG = 8-hydroxydeoxyguanosine; MP, maximum power; AP, average power; HRPC, heart rate percent change; ↓ = significant decrease; ↑ = significant increase; b = slight increase. ...
... Recently, several studies have arisen to explore the potential anti-fatigue effects of H 2 (Table 1) in healthy cohorts who performed either acute or chronic exercise, and shown the promise of intaking H 2 either before or after the exercise may help alleviate fatigue (Aoki et al., 2012;Da Ponte et al., 2018;Botek et al., 2019;LeBaron et al., 2019;Mikami et al., 2019;Dobashi et al., 2020;Hori et al., 2020;Shibayama et al., 2020;Timon Andrada et al., 2020;Dong et al., 2022). For example, intaking HRW before exercise has been shown to improve exercise-induced decline of muscle function (Aoki et al., 2012), and thus alleviate fatigue (Pantovic et al., 2016); and the inhalation of hydrogen-rich gas mixture after exercise can help attenuated the reduction in athletic performance (e.g., the Abbreviations: H 2 = molecular hydrogen; HRW, hydrogen-rich water; PPO, peak power output; RR, respiratory rate; HR, heart rate; RPE, ratings of perceived exertion; BAP, biological antioxidant potential; d-ROM, diacron-reactive oxygen metabolites; HG, hydrogen-rich gas mixture; 8-OHdG = 8-hydroxydeoxyguanosine; MP, maximum power; AP, average power; HRPC, heart rate percent change; ↓ = significant decrease; ↑ = significant increase; b = slight increase. ...
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Objective: In this study, we examined the effects of pre-exercise H 2 gas inhalation on physical fatigue (PF) and prefrontal cortex (PFC) activation during and after high-intensity cycling exercise. Methods: Twenty-four young men completed four study visits. On the first two visits, the maximum workload (W max ) of cycling exercise of each participant was determined. On each of the other two visits, participants inhaled 20 min of either H 2 gas or placebo gas after a baseline test of maximal voluntary isometric contraction (MVIC) of thigh. Then participants performed cycling exercise under their maximum workload. Ratings of perceived exertion (RPE), heart rate (HR) and the PFC activation by using functional near-infrared spectroscopy (fNIRS) was measured throughout cycling exercise. The MVIC was measured again after the cycling. Results: It was observed that compared to control, after inhaling H 2 gas, participants had significantly lower RPE at each workload phase ( p < 0.032) and lower HR at 50% W max , 75% W max , and 100% W max during cycling exercise ( p < 0.037); the PFC activation was also significantly increased at 75 and 100% W max ( p < 0.011). Moreover, the H 2 -induced changes in PF were significantly associated with that in PFC activation, that is, those who had higher PFC activation had lower RPE at 75% W max ( p = 0.010) and lower HR at 100% W ma x ( p = 0.016), respectively. Conclusion: This study demonstrated that pre-exercise inhalation of H 2 gas can alleviate PF, potentially by maintaining high PFC activation during high-intensity exercise in healthy young adults.
... Hydrogen-rich water (HRW) is one such safe nutrient that can be used as an alkalizing agent [19] and antioxidant [20,21], potentially helping to accelerate post-exercise recovery. Studies have shown the benefits of using HRW for reducing blood lactate levels [22,23], increasing blood pH [24], inhibiting exercise-induced oxidative stress [25], and thus alleviating exerciseinduced muscle fatigue [22]. However, the effects of taking HRW on athletic performance are uncertain [24,26], and only immediate effects of taking one dose of HRW have been explored; the benefits of taking HRW through a period of time on the performance of long-term high-intensity exercise (e.g., dragon boating) are still unknown. ...
... Hydrogen-rich water (HRW) is one such safe nutrient that can be used as an alkalizing agent [19] and antioxidant [20,21], potentially helping to accelerate post-exercise recovery. Studies have shown the benefits of using HRW for reducing blood lactate levels [22,23], increasing blood pH [24], inhibiting exercise-induced oxidative stress [25], and thus alleviating exerciseinduced muscle fatigue [22]. However, the effects of taking HRW on athletic performance are uncertain [24,26], and only immediate effects of taking one dose of HRW have been explored; the benefits of taking HRW through a period of time on the performance of long-term high-intensity exercise (e.g., dragon boating) are still unknown. ...
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(1) Background: Exercise that exceeds the body’s accustomed load can lead to oxidative stress and increased fatigue during intense training or competition, resulting in decreased athletic performance and an increased risk of injury, and the new medicinal H2 may be beneficial as an antioxidant. Therefore, we explored the effect of short-term supplementation of hydrogen-rich water (HRW) on the work performance and fatigue recovery of dragon boat athletes after training. (2) Methods: Eighteen dragon boat athletes who trained for 4 h a day (2 h in the morning and 2 h in the afternoon) were divided into an HRW group (n = 9) and a placebo water (PW) group (n = 9), drinking HRW or PW for 7 days. Each participant completed 30 s rowing dynamometer tests, monitoring the heart rate at baseline (i.e., Day 1) and after the intervention (on Day 8). (3) Result: Drinking HRW increased the maximum power and average power of the 30 s rowing test and decreased the maximum heart rate during the period. After the rowing test, the HRW group’s heart rate dropped significantly after 2 min of recovery, while the PW group’s heart rate did not drop. There was no significant difference between the 30 s rowing distance and the predicted duration of rowing 500 m. (4) Conclusions: Drinking HRW in the short term can effectively improve the power performance of dragon boat athletes and is conducive to the recovery of the heart rate after exercise, indicating that HRW may be a suitable means of hydration for athletes.
... In a recent clinical trial that was evaluated in a cohort of young and healthy people, the effects of inhaling 4% H 2 20 min per day for 7 days on exercise performance revealed ergogenic properties such as improved running performance and torso strength 20 . Although Sim M. and colleagues had reported the beneficial effect of H 2 inhalation on the increase of the antioxidant and anti-inflammatory response in healthy adults 21 , other groups found that H 2 only reduced delayed-onset muscle soreness after running downhill 22 or improved muscle function during exercise without any effect on blood oxidative markers 23 . These data suggest that still little is known about H 2 performance under healthy conditions and therefore requires further research. ...
... Unlike conventional drugs, a specific primary target has not yet been identified for H 2 , which would explain its broad efficacy in different diseases. H 2 showed great success in controlling various diseases 1,2,5 and is being evaluated for clinical applications in healthy people to improve performance and body condition 13,20,23 . However, it remains unknown how H 2 performs under healthy conditions. ...
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Molecular hydrogen (H2) has emerged as a new therapeutic option in several diseases and is widely adopted by healthy people. However, molecular data to support therapeutic functions attributed to the biological activities of H2 remain elusive. Here, using transcriptomic and metabolomic approaches coupled with biochemistry and micro-CT technics, we evaluated the effect of long-term (6 months) and daily use of H2 on liver function. Rats exposed 2 h daily to H2 either by drinking HRW (H2 dissolved in H2O) or by breathing 4% H2 gas showed reduced lipogenesis and enhanced lipolysis in the liver, which was associated with apparent loss of visceral fat and brown adipose tissue together with a reduced level of serum lipids. Both transcripts and metabolites enriched in H2-treated rats revealed alteration of amino acid metabolism pathways and activation of purine nucleotides and carbohydrate biosynthesis pathways. Analysis of the interaction network of genes and metabolites and correlation tests revealed that NADP is the central regulator of H2 induced metabolic alterations in the liver, which was further confirmed by an increase in the level of components of metabolic pathways that require NADP as substrate. Evidence of immune response regulation activity was also observed in response to exposure to H2. This work is the first to provide metabolomic and transcriptomic data to uncover molecular targets for the effect of prolonged molecular hydrogen treatment on liver metabolism.
... In sports science, the antioxidative effects of H 2 on athletes who repeatedly perform highintensity exercise have been demonstrated [9]. The intake of H 2 induces improvements in exercise performance [10,11] and recovery from muscle inflammation and fatigue [12,13]. Furthermore, H 2 supplementation has been shown to enhance fatty acid metabolism [14]. ...
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This study aimed to examine the effects of hydrogen gas (H2) produced by intestinal microbiota on participant conditioning to prevent intense exercise-induced damage. In this double-blind, randomized, crossover study, participants ingested H2-producing milk that induced intestinal bacterial H2 production or a placebo on the trial day, 4 h before performing an intense exercise at 75% maximal oxygen uptake for 60 min. Blood marker levels and respiratory variables were measured before, during, and after exercise. Visual analog scale scores of general and lower limb muscle soreness evaluated were 3.8- and 2.3-fold higher, respectively, on the morning after treatment than that before treatment during the placebo trial, but not during the test beverage consumption. Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentrations and production rates significantly increased with placebo consumption; no changes were observed with test beverage consumption. After exercise, relative blood lactate levels with H2-producing milk consumption were lower than those with placebo consumption. A negative correlation was observed between the variation of 8-OHdG and the area under the curve (AUC) of breath H2 concentrations. Lipid oxidation AUC was 1.3-fold higher significantly with H2-producing milk than with placebo consumption. Conclusively, activating intestinal bacterial H2 production by consuming a specific beverage may be a new strategy for promoting recovery and conditioning in athletes frequently performing intense exercises.
... ETECTION of fatigue is essential for works involving continuous efforts, such as in the case of firms [1], sportspersons, and athletes [2]- [4], in patients undergoing rehabilitation such as stroke and spinal cord injury (SCI) patients [5], [6]. In the context of contractile activity, muscle fatigue is characterized as a reduction in maximum force or power output [7]. ...
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p> An accurate estimation of muscle fatigue is critical for adaptive control of existing assistive devices, such as an exoskeleton, prosthesis, and functional electrical stimulation (FES)-based neuroprostheses. However, the estimation of muscle fatigue using surface electromyography (sEMG) for a long duration of time becomes challenging due to loosening of sEMG sensors, sweating, and other accidental failures. These problems can be potentially solved by forecasting future sEMG signals using initially recorded high-quality data points. For the first time, we attempt to forecast the fatigue-induced electromyography signal using the initial sEMG recorded for a shorter interval of time, during biceps curl with weights of 1 kg, 2 kg, 3 kg, and 4 kg. An attention-based deep CNN-BiLSTM neural network model that captures input sEMG dynamics to forecast future sEMG signals corresponding to fatigue state was trained and tested. An average mean absolute percentage error (MAPE) of 26.7% between forecasted and recorded sEMG was observed across eight subjects, five muscles, and four weights. In addition, the time domain features like integrated EMG (IEMG), root-mean-square (RMS) value, and variance of EMG (VEMG) were compared between forecasted and recorded sEMG (fatigue state), which yielded an average MAPE of 8%, 19.2%, and 31.7%, across eight subjects, five muscles, and four weights, for (IEMG and MAV), RMS, and (VEMG and SSI) respectively. The results encourage combining the proposed approach with wearable technology for forecasting fatigue-induced sEMG to drive stimulation devices like FES and robotic devices. </p
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Metabolic syndrome is characterized by cardiometabolic risk factors that include obesity, insulin resistance, hypertension and dyslipidemia. Oxidative stress is known to play a major role in the pathogenesis of metabolic syndrome. The objective of this study was to examine the effectiveness of hydrogen rich water (1.5-2 L/day) in an open label, 8-week study on 20 subjects with potential metabolic syndrome. Hydrogen rich water was produced, by placing a metallic magnesium stick into drinking water (hydrogen concentration; 0.55-0.65 mM), by the following chemical reaction; Mg + 2H(2)O --> Mg (OH)(2) + H(2). The consumption of hydrogen rich water for 8 weeks resulted in a 39% increase (p<0.05) in antioxidant enzyme superoxide dismutase (SOD) and a 43% decrease (p<0.05) in thiobarbituric acid reactive substances (TBARS) in urine. Further, subjects demonstrated an 8% increase in high density lipoprotein (HDL)-cholesterol and a 13% decrease in total cholesterol/HDL-cholesterol from baseline to week 4. There was no change in fasting glucose levels during the 8 week study. In conclusion, drinking hydrogen rich water represents a potentially novel therapeutic and preventive strategy for metabolic syndrome. The portable magnesium stick was a safe, easy and effective method of delivering hydrogen rich water for daily consumption by participants in the study.
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