Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning
Humans have a circadian rhythm for which the period varies among individuals. In the present study, we investigated the amount of natural phase delay of circadian rhythms after spending a day under dim light (Day 1 to Day 2) and the amount of phase advance due to light exposure (8000 lx, 4100 K) the...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Clocks & Sleep |
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| Online Access: | https://www.mdpi.com/2624-5175/5/4/41 |
| _version_ | 1797381563185364992 |
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| author | Michihiro Ohashi Taisuke Eto Toaki Takasu Yuki Motomura Shigekazu Higuchi |
| author_facet | Michihiro Ohashi Taisuke Eto Toaki Takasu Yuki Motomura Shigekazu Higuchi |
| author_sort | Michihiro Ohashi |
| collection | DOAJ |
| description | Humans have a circadian rhythm for which the period varies among individuals. In the present study, we investigated the amount of natural phase delay of circadian rhythms after spending a day under dim light (Day 1 to Day 2) and the amount of phase advance due to light exposure (8000 lx, 4100 K) the following morning (Day 2 to Day 3). The relationships of the phase shifts with the circadian phase, chronotype and sleep habits were also investigated. Dim light melatonin onset (DLMO) was investigated as a circadian phase marker on each day. In the 27 individuals used for the analysis, DLMO was delayed significantly (−0.24 ± 0.33 h, <i>p</i> < 0.01) from Day 1 to Day 2 and DLMO was advanced significantly (0.18 ± 0.36 h, <i>p</i> < 0.05) from Day 2 to Day 3. There was a significant correlation between phase shifts, with subjects who had a greater phase delay in the dim environment having a greater phase advance by light exposure (r = −0.43, <i>p</i> < 0.05). However, no significant correlations with circadian phase, chronotype or sleep habits were found. These phase shifts may reflect the stability of the phase, but do not account for an individual’s chronotype-related indicators. |
| first_indexed | 2024-03-08T20:54:17Z |
| format | Article |
| id | doaj.art-fec8ddeb29ec4fc6a0471f9f1af622cf |
| institution | Directory Open Access Journal |
| issn | 2624-5175 |
| language | English |
| last_indexed | 2024-03-08T20:54:17Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Clocks & Sleep |
| spelling | doaj.art-fec8ddeb29ec4fc6a0471f9f1af622cf2023-12-22T14:01:02ZengMDPI AGClocks & Sleep2624-51752023-10-015461562610.3390/clockssleep5040041Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following MorningMichihiro Ohashi0Taisuke Eto1Toaki Takasu2Yuki Motomura3Shigekazu Higuchi4Graduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka 815-8540, JapanResearch Fellow of the Japan Society for the Promotion of Science, Fukuoka 815-8540, JapanGraduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka 815-8540, JapanDepartment of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka 815-8540, JapanDepartment of Human Life Design and Science, Faculty of Design, Kyushu University, Fukuoka 815-8540, JapanHumans have a circadian rhythm for which the period varies among individuals. In the present study, we investigated the amount of natural phase delay of circadian rhythms after spending a day under dim light (Day 1 to Day 2) and the amount of phase advance due to light exposure (8000 lx, 4100 K) the following morning (Day 2 to Day 3). The relationships of the phase shifts with the circadian phase, chronotype and sleep habits were also investigated. Dim light melatonin onset (DLMO) was investigated as a circadian phase marker on each day. In the 27 individuals used for the analysis, DLMO was delayed significantly (−0.24 ± 0.33 h, <i>p</i> < 0.01) from Day 1 to Day 2 and DLMO was advanced significantly (0.18 ± 0.36 h, <i>p</i> < 0.05) from Day 2 to Day 3. There was a significant correlation between phase shifts, with subjects who had a greater phase delay in the dim environment having a greater phase advance by light exposure (r = −0.43, <i>p</i> < 0.05). However, no significant correlations with circadian phase, chronotype or sleep habits were found. These phase shifts may reflect the stability of the phase, but do not account for an individual’s chronotype-related indicators.https://www.mdpi.com/2624-5175/5/4/41circadian phasephotoentrainmentlightdim light melatonin onsetsleep |
| spellingShingle | Michihiro Ohashi Taisuke Eto Toaki Takasu Yuki Motomura Shigekazu Higuchi Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning Clocks & Sleep circadian phase photoentrainment light dim light melatonin onset sleep |
| title | Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning |
| title_full | Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning |
| title_fullStr | Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning |
| title_full_unstemmed | Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning |
| title_short | Relationship between Circadian Phase Delay without Morning Light and Phase Advance by Bright Light Exposure the Following Morning |
| title_sort | relationship between circadian phase delay without morning light and phase advance by bright light exposure the following morning |
| topic | circadian phase photoentrainment light dim light melatonin onset sleep |
| url | https://www.mdpi.com/2624-5175/5/4/41 |
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