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Akira Tsuda
Department of Psychology, Kurume University, Fukuoka 839-8502, Japan

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Journal article
Published: 05 June 2020 in Sustainability
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The objective of this study was to explore the relationship between subjective happiness and subjective and objective sleep. The participants were 24 healthy university students (11 males, 13 females; mean age 22.4 ± 2.1). Their subjective happiness was measured by the Japanese Subjective Happiness Scale (JSHS). Furthermore, their subjective and objective sleep evaluation was measured by Ogri-Shirakawa-Azumi sleep inventory MA version (OSA-MA) and a non-contact sheet sensor (SS). The results indicated that participants with higher subjective happiness had objectively shorter sleep onset latency, higher sleep efficiency, and lower heart rate during sleep. On the other hand, no such correlations were found between subjective sleep evaluation with OSA and subjective happiness. These results suggest that subjective happiness is related with the ability to more easily fall asleep and better sleep efficiency.

ACS Style

Hisayoshi Okamura; Kengo Mihara; Akira Tsuda; Toshihiro Morisaki; Yoshiyuki Tanaka; Yoshihisa Shoji. Subjective Happiness Is Associated with Objectively Evaluated Sleep Efficiency and Heart Rate during Sleep: An Exploratory Study Using Non-Contact Sheet Sensors. Sustainability 2020, 12, 1 .

AMA Style

Hisayoshi Okamura, Kengo Mihara, Akira Tsuda, Toshihiro Morisaki, Yoshiyuki Tanaka, Yoshihisa Shoji. Subjective Happiness Is Associated with Objectively Evaluated Sleep Efficiency and Heart Rate during Sleep: An Exploratory Study Using Non-Contact Sheet Sensors. Sustainability. 2020; 12 (11):1.

Chicago/Turabian Style

Hisayoshi Okamura; Kengo Mihara; Akira Tsuda; Toshihiro Morisaki; Yoshiyuki Tanaka; Yoshihisa Shoji. 2020. "Subjective Happiness Is Associated with Objectively Evaluated Sleep Efficiency and Heart Rate during Sleep: An Exploratory Study Using Non-Contact Sheet Sensors." Sustainability 12, no. 11: 1.

Journal article
Published: 02 June 2020 in Sustainability
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The current study aimed to examine the effects of personal growth (PG) on psychobiological responses at baseline and responsiveness to laboratory acute stress in students. Twenty-four healthy students were recruited as participants. Participants were screened from 203 candidates according to levels of PG using Ryff’s scale and classified into high and low PG groups. During the laboratory session, 13 high and 11 low PG participants underwent the Trier Social Stress Test. Heart rate and high-frequency (HF) heart rate variability were monitored throughout the experiment. Salivary free-3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) and perceived stress were measured at baseline, immediately after tasks and after a recovery period. Baseline and recovery perceived stress (tense arousal) were significantly lower in the high PG group compared with the low PG group. Free-MHPG and HF component returned to baseline levels during recovery significantly more rapidly in the high PG group compared with the low PG group. There were no significant group differences in heart rate. The results showed that high PG students have lower noradrenaline and higher parasympathetic nervous system activity before and after acute stress. These findings suggest a protective psychobiological pathway linking PG with better psychosomatic health in students.

ACS Style

Kengo Mihara; Hisayoshi Okamura; Yoshihisa Shoji; Kyoko Tashiro; Yukie Kinoshita; Akira Tsuda. Personal Growth and Psychobiological Stress Responsiveness to the Trier Social Stress Test in Students. Sustainability 2020, 12, 4497 .

AMA Style

Kengo Mihara, Hisayoshi Okamura, Yoshihisa Shoji, Kyoko Tashiro, Yukie Kinoshita, Akira Tsuda. Personal Growth and Psychobiological Stress Responsiveness to the Trier Social Stress Test in Students. Sustainability. 2020; 12 (11):4497.

Chicago/Turabian Style

Kengo Mihara; Hisayoshi Okamura; Yoshihisa Shoji; Kyoko Tashiro; Yukie Kinoshita; Akira Tsuda. 2020. "Personal Growth and Psychobiological Stress Responsiveness to the Trier Social Stress Test in Students." Sustainability 12, no. 11: 4497.

Randomized controlled trial
Published: 20 December 2018 in Nutrients
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Hops, the immature inflorescences of the female hop plant (Humulus lupulus L.) are one of the main components of beer and provides flavor and bitterness. β-Eudesmol, an oxygenated sesquiterpene, is reported to accumulate in a particular hop cultivar. Recently, we revealed that β-Eudesmol ingestion affected autonomic nerve activity in an animal model. The effect on humans has not been elucidated, therefore, we investigated the effects of β-Eudesmol on reducing objective and subjective markers related to sympathetic nerve activity after the application of mental stress in healthy participants. Fifty participants (male and female aged 20 to 50 years) were randomly assigned to two groups. Five minutes before taking the Trier Social Stress Test (TSST) as a mental stressor, participants in each group ingested a beverage containing β-Eudesmol, the active beverage, or a placebo beverage that did not contain β-Eudesmol. Saliva 3-methoxy-4-hydroxyphenylglycol (MHPG), a major product of noradrenaline breakdown and a representative marker of sympathetic nerve activity, was significantly lower just after the TSST in the active group compared with the placebo group. Saliva cortisol, a marker of the endocrine stress response system, was not significantly different between the two groups. No adverse events related to test beverage ingestion were observed. This is the first experimental evidence of β-Eudesmol effect for mental stress in human.

ACS Style

Kazuaki Ohara; Akane Misaizu; Yuji Kaneko; Takafumi Fukuda; Mika Miyake; Yutaka Miura; Hisayoshi Okamura; Jumpei Yajima; Akira Tsuda. β-Eudesmol, an Oxygenized Sesquiterpene, Reduces the Increase in Saliva 3-Methoxy-4-Hydroxyphenylglycol After the “Trier Social Stress Test” in Healthy Humans: A Randomized, Double-Blind, Placebo-Controlled Cross-Over Study. Nutrients 2018, 11, 9 .

AMA Style

Kazuaki Ohara, Akane Misaizu, Yuji Kaneko, Takafumi Fukuda, Mika Miyake, Yutaka Miura, Hisayoshi Okamura, Jumpei Yajima, Akira Tsuda. β-Eudesmol, an Oxygenized Sesquiterpene, Reduces the Increase in Saliva 3-Methoxy-4-Hydroxyphenylglycol After the “Trier Social Stress Test” in Healthy Humans: A Randomized, Double-Blind, Placebo-Controlled Cross-Over Study. Nutrients. 2018; 11 (1):9.

Chicago/Turabian Style

Kazuaki Ohara; Akane Misaizu; Yuji Kaneko; Takafumi Fukuda; Mika Miyake; Yutaka Miura; Hisayoshi Okamura; Jumpei Yajima; Akira Tsuda. 2018. "β-Eudesmol, an Oxygenized Sesquiterpene, Reduces the Increase in Saliva 3-Methoxy-4-Hydroxyphenylglycol After the “Trier Social Stress Test” in Healthy Humans: A Randomized, Double-Blind, Placebo-Controlled Cross-Over Study." Nutrients 11, no. 1: 9.

Perspective
Published: 11 December 2018 in Sustainability
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After delineating the roots of harmony in the literature from both the Eastern and the Western perspectives, the paper introduces the new Psychology of harmony in terms of harmonization that widens the perspective calling for psychological contributions regarding components, processes and building strengths in a preventive perspective. The complex construction of Harmony from a psychological perspective underlines the concept of relationality. Harmony results at three main points, with oneself, with others, and with nature/the natural world, also taking into account the spatial and temporal perspectives. The Psychology of harmony as harmonization represents a pillar for a new research area in the psychology of sustainability and sustainable development, considering harmonization in geographical and temporal perspectives, including meaningful construction processes from the past, to the present, and into the future using reflexivity processes at the individual, group, community, social, and national levels. Introducing the innovative psychology of harmony as harmonization the present article offers promising perspectives for research and intervention with the aim to individuate and foster new strengths from a preventive perspective.

ACS Style

Annamaria Di Fabio; Akira Tsuda. The Psychology of Harmony and Harmonization: Advancing the Perspectives for the Psychology of Sustainability and Sustainable Development. Sustainability 2018, 10, 4726 .

AMA Style

Annamaria Di Fabio, Akira Tsuda. The Psychology of Harmony and Harmonization: Advancing the Perspectives for the Psychology of Sustainability and Sustainable Development. Sustainability. 2018; 10 (12):4726.

Chicago/Turabian Style

Annamaria Di Fabio; Akira Tsuda. 2018. "The Psychology of Harmony and Harmonization: Advancing the Perspectives for the Psychology of Sustainability and Sustainable Development." Sustainability 10, no. 12: 4726.

Original research
Published: 01 August 2018 in Psychology Research and Behavior Management
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Mediating effects of perceived stress on the relationship of positivity with negative and positive affect Satoshi Horiuchi,1 Akira Tsuda,2 Kenichiro Yoneda,3 Shuntaro Aoki4,5 1Faculty of Social Welfare, Iwate Prefectural University, Iwate, Japan; 2Department of Psychology, Kurume University, Fukuoka, Japan; 3Graduate School of Psychology, Kurume University, Fukuoka, Japan; 4Japan Society for the Promotion of Science, Tokyo, Japan; 5Graduate School of Psychological Science, Health Sciences University of Hokkaido, Hokkaido, Japan Background: Positivity refers to “a general tendency to view life and experiences with a positive outlook”. Enhanced positivity has been linked with decreased negative affect and increased ­positive affect, but rather little is known about the factors that mediate these relationships. One potential such factor is perceived stress, which refers to how one appraises life situations as stressful. This study examined the mediating effects of perceived stress on the associations of positivity with negative and positive affect. Two hypotheses were tested: 1) positivity is negatively associated with perceived stress, which in turn is positively associated with negative affect, and 2) positivity is negatively associated with perceived stress, which in turn is negatively associated with positive affect. Methods: An online survey was conducted with 100 Japanese men and 100 Japanese women who were members of a survey company in January 2018. They completed questionnaires on positivity, perceived stress, and negative and positive affect. All survey procedures were managed and conducted by a web-survey company. Results: Mediation analyses indicated that perceived stress was a mediator in the relationship between positivity and negative affect. Perceived stress was also found to be a mediator in the relationship between positivity and positive affect. Conclusion: Positivity was found to be associated with negative affect and positive affect via perceived stress. Keywords: positivity, perceived stress, negative affect, positive affect, positive orientation

ACS Style

Satoshi Horiuchi; Akira Tsuda; Kenichiro Yoneda; Shuntaro Aoki. Mediating effects of perceived stress on the relationship of positivity with negative and positive affect. Psychology Research and Behavior Management 2018, ume 11, 299 -303.

AMA Style

Satoshi Horiuchi, Akira Tsuda, Kenichiro Yoneda, Shuntaro Aoki. Mediating effects of perceived stress on the relationship of positivity with negative and positive affect. Psychology Research and Behavior Management. 2018; ume 11 ():299-303.

Chicago/Turabian Style

Satoshi Horiuchi; Akira Tsuda; Kenichiro Yoneda; Shuntaro Aoki. 2018. "Mediating effects of perceived stress on the relationship of positivity with negative and positive affect." Psychology Research and Behavior Management ume 11, no. : 299-303.

Journal article
Published: 01 March 2018 in Psychology Research and Behavior Management
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Coping as a mediator of the relationship between stress mindset and psychological stress response: a pilot study Satoshi Horiuchi,1 Akira Tsuda,2 Shuntaro Aoki,3,4 Kenichiro Yoneda,5 Yusuke Sawaguchi6 1Faculty of Social Welfare, Iwate Prefectural University, Iwate, 2Department of Psychology, Kurume University, Fukuoka, 3Research Fellow of Japan Society for the Promotion of Science, Tokyo, 4Graduate School of Psychological Science, Health Sciences University of Hokkaido, Hokkaido, 5Graduate School of Psychology, Kurume University, Fukuoka, 6Graduate School of Social Welfare, Iwate Prefectural University, Iwate, Japan Background: Coping, the cognitive and behavioral effort required to manage the effects of stressors, is important in determining psychological stress responses (ie, the emotional, behavioral, and cognitive responses to stressors). Coping was classified into categories of emotional expression (eg, negative feelings and thoughts), emotional support seeking (eg, approaching loved ones to request encouragement), cognitive reinterpretation (eg, reframing a problem positively), and problem solving (eg, working to solve the problem). Stress mindset refers to the belief that stress has enhancing (stress-is-enhancing mindset) or debilitating consequences (stress-is-debilitating mindset). This study examined whether coping mediated the relationship between stress mindset and psychological stress responses. Psychological stress responses were conceptualized as depression-anxiety, irritability-anger, and helplessness. The following two hypotheses were tested: 1) a stronger stress-is-enhancing mindset is associated with less frequent use of emotional expression, emotional support seeking, and problem solving, which in turn is associated with lower levels of depression-anxiety, irritability-anger, and helplessness; 2) a stronger stress-is-debilitating mindset is associated with more frequent use of these coping strategies, which in turn is associated with higher levels of these psychological stress responses. Materials and methods: The participants were 30 male and 94 female undergraduate and graduate students (mean age =20.4 years). Stress mindset, coping, and psychological stress responses were measured using self-report questionnaires. Six mediation analyses were performed with stress-is-enhancing mindset or stress-is-debilitating mindset as the independent variable, one of the psychological stress responses as the dependent variable, and the four coping strategies as mediators. Results: Emotional expression partially mediated the relationship between a strong stress-is-debilitating mindset and higher irritability-anger levels. The other three coping strategies did not exhibit mediating effects. None of the coping strategies mediated the relationship between a stress-is-enhancing mindset and psychological stress responses. Conclusion: These results provide initial evidence that stress mindset is associated with psychological stress responses, through coping strategies. Keywords: stress-is-enhancing mindset, stress-is-debilitating mindset, coping, emotional expression, psychological stress responses

ACS Style

Satoshi Horiuchi; Akira Tsuda; Shuntaro Aoki; Kenichiro Yoneda; Yusuke Sawaguchi. Coping as a mediator of the relationship between stress mindset and psychological stress response: a pilot study. Psychology Research and Behavior Management 2018, ume 11, 47 -54.

AMA Style

Satoshi Horiuchi, Akira Tsuda, Shuntaro Aoki, Kenichiro Yoneda, Yusuke Sawaguchi. Coping as a mediator of the relationship between stress mindset and psychological stress response: a pilot study. Psychology Research and Behavior Management. 2018; ume 11 ():47-54.

Chicago/Turabian Style

Satoshi Horiuchi; Akira Tsuda; Shuntaro Aoki; Kenichiro Yoneda; Yusuke Sawaguchi. 2018. "Coping as a mediator of the relationship between stress mindset and psychological stress response: a pilot study." Psychology Research and Behavior Management ume 11, no. : 47-54.

Journal article
Published: 08 January 2016 in Japanese Psychological Research
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ACS Style

Akira Tsuda; Kwang‐Kuo Hwang. Editorial: The Construction of Culture-Inclusive Approaches in Psychology. Japanese Psychological Research 2016, 58, 1 -3.

AMA Style

Akira Tsuda, Kwang‐Kuo Hwang. Editorial: The Construction of Culture-Inclusive Approaches in Psychology. Japanese Psychological Research. 2016; 58 (1):1-3.

Chicago/Turabian Style

Akira Tsuda; Kwang‐Kuo Hwang. 2016. "Editorial: The Construction of Culture-Inclusive Approaches in Psychology." Japanese Psychological Research 58, no. 1: 1-3.

Journal article
Published: 01 January 2015 in Psychology
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In this study, an investigation based on an effectiveness study trial without special limitations was carried out regarding how 14 days’ continuous soup intake would change the mood of the participants and their salivary cortisol levels between awakening and evening. The participants consisted of 16 healthy workers who agreed to participate in the experiment. The participants led their normal daily lives without consuming soup for the first 14 days (controlled condition), and then consumed their chosen soup once a day, at approximately 3 p.m., for the next 14 days (soup condition). Their salivary cortisol levels were measured when they woke up in the morning (awakening) and at 5 p.m. on the last day of each condition, while their mood was evaluated by questionnaire at 5 p.m. every day. The irritation-anger score of the soup condition was significantly lower than that of the controlled condition, and the difference in the salivary cortisol level between awakening and evening in the soup condition was significantly higher compared with the controlled condition. As a result, this study suggests that continuous soup intake under conditions of free choice in the afternoon at the workplace may be effective in relieving stress of worker’s body and mind.

ACS Style

Jumpei Yajima; Akira Tsuda; Hisayoshi Okamura; Hidenori Urata; Akira Matsubara; Kengo Mihara; Takashi Isomura; Kazuhiko Takeda; Naoki Midoh. Effects of Soup Intake for Fourteen Days on the Mood and the Difference in Cortisol of Awakening and Evening in the Clerical Employees: An Effectiveness Study Trial. Psychology 2015, 06, 1108 -1113.

AMA Style

Jumpei Yajima, Akira Tsuda, Hisayoshi Okamura, Hidenori Urata, Akira Matsubara, Kengo Mihara, Takashi Isomura, Kazuhiko Takeda, Naoki Midoh. Effects of Soup Intake for Fourteen Days on the Mood and the Difference in Cortisol of Awakening and Evening in the Clerical Employees: An Effectiveness Study Trial. Psychology. 2015; 06 (09):1108-1113.

Chicago/Turabian Style

Jumpei Yajima; Akira Tsuda; Hisayoshi Okamura; Hidenori Urata; Akira Matsubara; Kengo Mihara; Takashi Isomura; Kazuhiko Takeda; Naoki Midoh. 2015. "Effects of Soup Intake for Fourteen Days on the Mood and the Difference in Cortisol of Awakening and Evening in the Clerical Employees: An Effectiveness Study Trial." Psychology 06, no. 09: 1108-1113.

Brief report
Published: 14 September 2014 in Psychophysiology
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Levels of 3‐methoxy‐4‐hydroxyphenylglycol (MHPG) may reflect central noradrenergic activity. In this study, we investigated salivary MHPG changes after awakening, and explored their relationships with cortisol and peripheral autonomic activity. The participants were 25 college students. Saliva samples were collected on awakening and 30 min after awakening to determine MHPG and cortisol. Ambulatory electrocardiograms were obtained to assess heart rate, cardiac sympathetic index (CSI), and cardiac vagal index (CVI) before and after awakening. MHPG levels increased significantly during the first 30 min after awakening. Similarly, cortisol, heart rate, and CSI increased during the 30 min after awakening, but changes in MHPG did not correlate with changes in cortisol, heart rate, CSI, and CVI during that period. This study demonstrated that salivary MHPG levels increase after awakening, in common with cortisol, heart rate, and cardiac sympathetic activity.

ACS Style

Nagisa Sugaya; Shuhei Izawa; Ryuichiro Yamamoto; Namiko Ogawa; Jumpei Yajima; Hisayoshi Okamura; Satoshi Horiuchi; Akira Tsuda; Shinobu Nomura. Salivary 3-methoxy-4-hydroxyphenylglycol increases after awakening in healthy young adults. Psychophysiology 2014, 52, 425 -428.

AMA Style

Nagisa Sugaya, Shuhei Izawa, Ryuichiro Yamamoto, Namiko Ogawa, Jumpei Yajima, Hisayoshi Okamura, Satoshi Horiuchi, Akira Tsuda, Shinobu Nomura. Salivary 3-methoxy-4-hydroxyphenylglycol increases after awakening in healthy young adults. Psychophysiology. 2014; 52 (3):425-428.

Chicago/Turabian Style

Nagisa Sugaya; Shuhei Izawa; Ryuichiro Yamamoto; Namiko Ogawa; Jumpei Yajima; Hisayoshi Okamura; Satoshi Horiuchi; Akira Tsuda; Shinobu Nomura. 2014. "Salivary 3-methoxy-4-hydroxyphenylglycol increases after awakening in healthy young adults." Psychophysiology 52, no. 3: 425-428.

Randomized controlled trial
Published: 03 June 2014 in Nutrition Journal
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L-ornithine is a non-essential, non-protein amino acid. Although L-ornithine is contained in various foods, the amount is usually small. Recently, studies have shown that orally administered L-ornithine reduced the stress response in animals. From these findings, we speculated that L-ornithine may play a role in the relieve of stress and improve sleep and fatigue symptoms in humans. Through a randomised, double-blind, placebo-controlled clinical study, we asked if L-ornithine could be beneficial to stress and sleep in healthy workers. Fifty-two apparently healthy Japanese adults who had previously felt slight stress as well as fatigue were recruited to be study participants and were randomly divided into either the L-ornithine (400 mg/day) or placebo group. They orally consumed the respective test substance every day for 8 weeks. Serum was collected for the assessment of cortisol and dehydroepiandrosterone-sulphate (DHEA-S). Perceived mood and quality of sleep were measured by the Profile of Mood States (POMS), Athens Insomnia Scale (AIS), and Ogri-Shirakawa-Azumi sleep inventory MA version (OSA-MA). Serum cortisol levels and the cortisol/DHEA-S ratio were significantly decreased in the L-ornithine group in comparison with the placebo group. Also, anger was reduced and perceived sleep quality was improved in the L-ornithine group. L-ornithine supplementation has the potential to relieve stress and improve sleep quality related to fatigue, both objectively and subjectively.

ACS Style

Mika Miyake; Takayoshi Kirisako; Takeshi Kokubo; Yutaka Miura; Koji Morishita; Hisayoshi Okamura; Akira Tsuda. Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers. Nutrition Journal 2014, 13, 53 -53.

AMA Style

Mika Miyake, Takayoshi Kirisako, Takeshi Kokubo, Yutaka Miura, Koji Morishita, Hisayoshi Okamura, Akira Tsuda. Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers. Nutrition Journal. 2014; 13 (1):53-53.

Chicago/Turabian Style

Mika Miyake; Takayoshi Kirisako; Takeshi Kokubo; Yutaka Miura; Koji Morishita; Hisayoshi Okamura; Akira Tsuda. 2014. "Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers." Nutrition Journal 13, no. 1: 53-53.

Journal article
Published: 01 January 2013 in BioPsychoSocial Medicine
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Residual alcohol effects on physiological and psychological symptoms are commonly experienced the morning after alcohol consumption. The purpose of this study was to assess the effects of L-ornithine on subjective feelings and salivary stress markers the morning after alcohol consumption and to investigate whether L-ornithine acutely accelerates ethanol metabolism. This study had a randomized, placebo-controlled, double-masked crossover design. Subjects were all healthy Japanese adults with the ‘flusher’ phenotype for alcohol tolerance. In experiment 1, 11 subjects drank 0.4 g/kg body weight alcohol 1.5 h before their usual bedtime. Half an hour after drinking, they ingested either a placebo or 400 mg ornithine. The next morning on awakening, subjects completed a questionnaire containing a visual analog scale (VAS), the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA), and a profile of mood states (POMS) and collected a saliva sample for measurement of salivary stress markers (cortisol, secretory immunoglobulin A, and α-amylase). In experiment 2, placebo or 400 mg ornithine were administrated to 16 subjects both before and after drinking, and the feeling of drunkenness, breath ethanol concentration and one-leg standing time were repeatedly investigated until 180 min after alcohol consumption. There were significant decreases in “awareness”, “feeling of fatigue” and “lassitude” VAS scores and in “anger-hostility” and “confusion” POMS scores and a significant increase in “sleep length” in the OSA-MA test. Salivary cortisol concentrations on awakening were reduced after ornithine supplementation. There were no differences between ornithine and placebo in any of the subjective or physiological parameters of acute alcohol metabolism. Taking 400 mg ornithine after alcohol consumption improved various negative feelings and decreased the salivary stress marker cortisol the next morning. These effects were not caused by an increase in acute alcohol metabolism.

ACS Style

Takeshi Kokubo; Emiko Ikeshima; Takayoshi Kirisako; Yutaka Miura; Masahisa Horiuchi; Akira Tsuda. A randomized, double-masked, placebo-controlled crossover trial on the effects of L-ornithine on salivary cortisol and feelings of fatigue of flushers the morning after alcohol consumption. BioPsychoSocial Medicine 2013, 7, 6 -6.

AMA Style

Takeshi Kokubo, Emiko Ikeshima, Takayoshi Kirisako, Yutaka Miura, Masahisa Horiuchi, Akira Tsuda. A randomized, double-masked, placebo-controlled crossover trial on the effects of L-ornithine on salivary cortisol and feelings of fatigue of flushers the morning after alcohol consumption. BioPsychoSocial Medicine. 2013; 7 (1):6-6.

Chicago/Turabian Style

Takeshi Kokubo; Emiko Ikeshima; Takayoshi Kirisako; Yutaka Miura; Masahisa Horiuchi; Akira Tsuda. 2013. "A randomized, double-masked, placebo-controlled crossover trial on the effects of L-ornithine on salivary cortisol and feelings of fatigue of flushers the morning after alcohol consumption." BioPsychoSocial Medicine 7, no. 1: 6-6.

Journal article
Published: 19 August 2012 in Functional Foods in Health and Disease
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Seventeen adult male and female subjects participated in a clinical trial using an open-label trial to evaluate the effectiveness of pyrroloquinoline quinone (PQQ) on stress, fatigue, quality of life and sleep. They ingested 20 mg of PQQ daily for 8 weeks. Changes in stress, fatigue, quality of life measures and sleep were evaluated using various inventories and questionnaires. For example, the results of the Profile of Mood States-Short Form revealed that all six measures of vigor, fatigue, tension-anxiety, depression, anger-hostility and confusion were significantly improved following PQQ administration compared with scores for those measures before administration of PQQ. Measures for quality of life, appetite, sleep, obsession and pain, also improved significantly. The results of the Oguri-Shirakawa-Azumi Sleep Inventory (Middle Aged and Aged version) showed significant improvement in sleepiness at awakening, sleep onset and maintenance, and sleep duration. For validation, the Pittsburgh Sleep Quality Index Japanese version also showed significant improvement in sleep-related behavior. Furthermore, the changes in these global scores were correlated with changes in the cortisol awakening response (R = -0.55), i.e. the effects of PQQ on improvement of sleep quality are supported by a biomarker.Keywords: Pyrroloquinoline quinone, stress, fatigue, quality of life, sleep

ACS Style

Masahiko Nakano; Tetsuro Yamamoto; Hisayoshi Okamura; Akira Tsuda; Yasuyuki Kowatari. Effects of Oral Supplementation with Pyrroloquinoline Quinone on Stress, Fatigue, and Sleep. Functional Foods in Health and Disease 2012, 2, 307 .

AMA Style

Masahiko Nakano, Tetsuro Yamamoto, Hisayoshi Okamura, Akira Tsuda, Yasuyuki Kowatari. Effects of Oral Supplementation with Pyrroloquinoline Quinone on Stress, Fatigue, and Sleep. Functional Foods in Health and Disease. 2012; 2 (8):307.

Chicago/Turabian Style

Masahiko Nakano; Tetsuro Yamamoto; Hisayoshi Okamura; Akira Tsuda; Yasuyuki Kowatari. 2012. "Effects of Oral Supplementation with Pyrroloquinoline Quinone on Stress, Fatigue, and Sleep." Functional Foods in Health and Disease 2, no. 8: 307.

Journal article
Published: 10 May 2011 in Japanese Psychological Research
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The purpose of the present study was to investigate the relationship between the cortisol awakening response (CAR) and perceived loneliness on work days and weekends. Ninety female full‐time workers (20–50 years old) were recruited for this study. Loneliness was evaluated using the Revised UCLA Loneliness Scale, and participants were classified into high (average + 1 SD; n = 20) or low loneliness groups (average – 1 SD; n = 20). The saliva samples were collected on work days and weekends. Participants were instructed to collect saliva on two occasions each day: immediately on awakening and 30 minutes after awakening. The CAR was higher on weekends in the high loneliness group than in the low loneliness group. There were significant differences in the CAR in the low loneliness group between work days and weekends, but not in the high loneliness group. These results indicated that the CAR in high loneliness people was not significantly different between work days and weekends due to a hypothalamic‐pituitary‐adrenal system that is always activated.

ACS Style

Hisayoshi Okamura; Akira Tsuda; Toyojiro Matsuishi. The relationship between perceived loneliness and cortisol awakening responses on work days and weekends1. Japanese Psychological Research 2011, 53, 113 -120.

AMA Style

Hisayoshi Okamura, Akira Tsuda, Toyojiro Matsuishi. The relationship between perceived loneliness and cortisol awakening responses on work days and weekends1. Japanese Psychological Research. 2011; 53 (2):113-120.

Chicago/Turabian Style

Hisayoshi Okamura; Akira Tsuda; Toyojiro Matsuishi. 2011. "The relationship between perceived loneliness and cortisol awakening responses on work days and weekends1." Japanese Psychological Research 53, no. 2: 113-120.

Research article
Published: 05 January 2011 in Stress and Health
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A host of interventions are now known to be helpful to alleviate subjective distress and improve well‐being in dementia caregivers. However, few intervention studies have focused on measures of physical health, and none have examined cortisol as an outcome—despite the fact that cortisol is regarded as a crucial biological intermediary by which chronic stress leads to disease. In this study, we examined demographic and psychosocial factors as predictors of salivary cortisol at a baseline assessment, among a sample of 175 Latino/Hispanic and Caucasian women caring for a family member with dementia. We also examined the influence of a cognitive–behaviour‐based psychoeducational intervention (Coping with Caregiving) on cortisol at a post‐treatment assessment, compared with a minimal support condition. Results revealed that caregivers with high intensity caregiving situations, characterized by long hours of care and co‐residence with the care recipient, tended to have less adaptive cortisol patterns. However, these ‘at‐risk’ caregivers benefited most from the Coping with Caregiving intervention and had more normal cortisol patterns at post‐treatment, compared with caregivers in the control condition. Copyright © 2011 John Wiley & Sons, Ltd.

ACS Style

Jason M. Holland; Larry W. Thompson; Michael A. Cucciare; Akira Tsuda; Hisayoshi Okamura; David Spiegel; Natalie L. Rasgon; Dolores Gallagher-Thompson. Cortisol outcomes among caucasian and latina/hispanic women caring for a family member with dementia: a preliminary examination of psychosocial predictors and effects of a psychoeducational intervention. Stress and Health 2011, 27, 334 -346.

AMA Style

Jason M. Holland, Larry W. Thompson, Michael A. Cucciare, Akira Tsuda, Hisayoshi Okamura, David Spiegel, Natalie L. Rasgon, Dolores Gallagher-Thompson. Cortisol outcomes among caucasian and latina/hispanic women caring for a family member with dementia: a preliminary examination of psychosocial predictors and effects of a psychoeducational intervention. Stress and Health. 2011; 27 (4):334-346.

Chicago/Turabian Style

Jason M. Holland; Larry W. Thompson; Michael A. Cucciare; Akira Tsuda; Hisayoshi Okamura; David Spiegel; Natalie L. Rasgon; Dolores Gallagher-Thompson. 2011. "Cortisol outcomes among caucasian and latina/hispanic women caring for a family member with dementia: a preliminary examination of psychosocial predictors and effects of a psychoeducational intervention." Stress and Health 27, no. 4: 334-346.

Journal article
Published: 31 December 2010 in International Journal of Psychophysiology
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The aim of this study was to examine the association between self-reported sleeping time and psychobiological stress responses [3-Methoxy-4-hydroxyphenylglycol (MHPG) and Secretory immunoglobulin A (IgA), perceived stress responses]. Thirty seven healthy men and women were recruited, and participants were divided according to the habitual number of hours of sleep as follows: adequate sleepers (AS) (6–8 h sleep per night regularly) (N = 22) and short sleepers (SS) (less than 5 h sleep per night regularly) (N = 15). Salivary MHPG, s-IgA and perceived stress were measured at baseline, immediately after task and recovery period. An increase in free-MHPG during the task period was observed in AS although free-MHPG increased only after the task period in SS. The level of s-IgA in both groups significantly increased during the task period, and quickly returned to a basal level during the recovery period. The results show that less than 5 h of sleep was associated with different responsiveness to the Stroop color word conflict task compared to sufficient sleep, especially in the NA system.

ACS Style

Hisayoshi Okamura; Akira Tsuda; Jumpei Yajima; Hamer Mark; Satoshi Horiuchi; Natsuki Toyoshima; Toyojirou Matsuishi. Short sleeping time and psychobiological responses to acute stress. International Journal of Psychophysiology 2010, 78, 209 -214.

AMA Style

Hisayoshi Okamura, Akira Tsuda, Jumpei Yajima, Hamer Mark, Satoshi Horiuchi, Natsuki Toyoshima, Toyojirou Matsuishi. Short sleeping time and psychobiological responses to acute stress. International Journal of Psychophysiology. 2010; 78 (3):209-214.

Chicago/Turabian Style

Hisayoshi Okamura; Akira Tsuda; Jumpei Yajima; Hamer Mark; Satoshi Horiuchi; Natsuki Toyoshima; Toyojirou Matsuishi. 2010. "Short sleeping time and psychobiological responses to acute stress." International Journal of Psychophysiology 78, no. 3: 209-214.