Science June 1999 PMID 10381883

Stability, precision, and near-24-hour period of the human circadian pacemaker.

C A Czeisler, J F Duffy, T L Shanahan, E N Brown, J F Mitchell, D W Rimmer, J M Ronda, E J Silva, J S Allan, J S Emens, D J Dijk, R E Kronauer

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Mentions

125
Peak: 23 in Feb 2023
across 5 sources since Dec 2018

Extended reach

213,382
potential audience

Total likes

268

Video views

3,717

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Dec 2018 – Nov 2025

Where it's discussed

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AI synopsis

What people are saying

Discussions frequently emphasize the importance of understanding circadian rhythms, with users discussing the impact of daylight saving time on their sleep patterns. For instance, one participant shared their family's struggles with evening light disrupting melatonin production, showing a personal connection to the research's findings. The tone across many posts is earnest and concerned, using phrases like 'our body clocks are so important' to reflect the potential effects on health and well-being.

AgreementModerate agreement

Most discussions express support for the findings of the publication, although there is some debate about specific details.

InterestHigh interest

Users demonstrate a strong curiosity surrounding circadian rhythms and their practical implications.

EngagementModerate engagement

While many posts share personal experiences, some users dive deeper into the scientific aspects, debating the nuances of the research.

ImpactHigh impact

Several participants highlight the significant implications of aligning societal time with natural rhythms, suggesting a high potential for practical changes.

Abstract in brief

  • Research shows that human circadian rhythms, particularly for melatonin and core body temperature, average around 24.18 hours for both young and older individuals when studied under controlled lighting conditions.
  • Contrary to previous beliefs, humans have a more consistent circadian period similar to that of other species, rather than a wide range of 13 to 65 hours.
  • This understanding is crucial for addressing disrupted sleep patterns, especially in older adults, helping to better comprehend related health issues.

Top posts

Most liked on X and Bluesky
Save Standard Time
@SaveStandard · X

Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange: https://t.co/AAFVtEa9PS https://t.co/C3CilBFbRE

Aug 20, 2023 · 34 likes · 12 shares · 12,907 followers View post →
Save Standard Time
@SaveStandard · X

Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performance. Watch our full video here: https://t.co/AAFVtEa9PS https://t.co/7Y46QpPxGu

May 5, 2023 · 28 likes · 11 shares · 12,907 followers View post →
Save Standard Time
@SaveStandard · X

What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #EndDST #SaveStandardTime #SleepHealth https://t.co/Iw1UFPZgXC

Feb 2, 2023 · 24 likes · 14 shares · 12,907 followers View post →
奏雪❄️@Kanayuki@mas.to
@Kanayuki_Chan · X

参考资料: 1:https://t.co/YTUT2STIwW 2:https://t.co/QyPTeGiMSL 3:https://t.co/jLseCLyxBD 有兴趣的话 可以作为扩展阅读点开看看 4:https://t.co/f4wyX44n6R {5/5 end}

Nov 18, 2024 · 15 likes · 7,342 followers View post →
木花
@springflower_22 · X

人間の概日リズム周期は平均24.18時間と示した論文。1999年のものだが今も引用される。24.18±0.4時間の範囲に被験者24人全員がおさまり個人間のばらつきは少ない。被験者を28時間周期で生活させる強制脱同調という手法で深部体温やメラトニン分泌を測定した。 DOI: 10.1126/science.284.5423.2177

Nov 16, 2022 · 15 likes · 3 shares · 1,758 followers View post →
Karin Johnson
@drsleepykarin · X

Struggling to fall asleep at night or get up in the AM. Parent trying to get their kid out the door for school. Our Body clocks are so important. The Science of Clock Change 3: Understanding Circadian Rhythms https://t.co/pO1PheF4Wg via @YouTube @SaveStandard #Insomnia #Sleep

Sep 23, 2024 · 8 likes · 3 shares · 2,336 followers View post →

All mentions

NormalTid AllTid
@normaltidalltid.bsky.social · Bluesky

The Science about clock change between Normal Time and 'summertime' - part 3 @EUCouncil #standardtime #naturaltime #naturaltimezone #StoppTimeChange #abolishsummertime #abolishDST #ditchsummertime youtu.be/uu9n7sVkh4o

Jun 17, 2025 · 1 share View post →
The Oven Bird
@RedBrickPoetry · X

@timtam_slamtam @KiraJosei @SaveStandard "waste of daylight"" Tell me what does morning sunlight do for your eyes and your circadian cycles? What does evening light do & how is it connected to the release of melatonin? bc more light in the evening messes my entire family up and we all hate DST. https://t.co/M8l3yxJ1gB

May 1, 2025 · 4 likes · 179 followers View post →
J. M. Hereword
@roquefort888 · X

@tracegallagher #3 https://t.co/R9M2ZqbwTO

Apr 5, 2025 · 216 followers View post →
The Oven Bird
@RedBrickPoetry · X

@deidrejowen https://t.co/EROb8wzEKS

Mar 19, 2025 · 179 followers View post →
The Oven Bird
@RedBrickPoetry · X

@kkevinaten @kevin62387 @TheMoralLibert1 The Science of Clock Change 3: Understanding Circadian Rhythms https://t.co/EROb8wz6Vk

Mar 19, 2025 · 179 followers View post →
Alba
@Violeta_sol_ · X

@IA_Noelia_ Esto no es cierto, el reloj interno humano es ligeramente superior a 24h, pero no 48h https://t.co/UmGO8gXZoR

Nov 26, 2024 · 1 like · 35 followers View post →
奏雪❄️@Kanayuki@mas.to
@Kanayuki_Chan · X

参考资料: 1:https://t.co/YTUT2STIwW 2:https://t.co/QyPTeGiMSL 3:https://t.co/jLseCLyxBD 有兴趣的话 可以作为扩展阅读点开看看 4:https://t.co/f4wyX44n6R {5/5 end}

Nov 18, 2024 · 15 likes · 7,342 followers View post →
robert b mack
@robertbmack2 · X

RT @drsleepykarin: Struggling to fall asleep at night or get up in the AM. Parent trying to get their kid out the door for school. Our Bo…

Sep 24, 2024 · 3 shares · 3,159 followers View post →
Save Standard Time
@SaveStandard · X

RT @drsleepykarin: Struggling to fall asleep at night or get up in the AM. Parent trying to get their kid out the door for school. Our Bo…

Sep 24, 2024 · 3 shares · 12,907 followers View post →
Betty
@BettyBersig5 · X

RT @drsleepykarin: Struggling to fall asleep at night or get up in the AM. Parent trying to get their kid out the door for school. Our Bo…

Sep 23, 2024 · 3 shares · 842 followers View post →
Karin Johnson
@drsleepykarin · X

Struggling to fall asleep at night or get up in the AM. Parent trying to get their kid out the door for school. Our Body clocks are so important. The Science of Clock Change 3: Understanding Circadian Rhythms https://t.co/pO1PheF4Wg via @YouTube @SaveStandard #Insomnia #Sleep

Sep 23, 2024 · 8 likes · 3 shares · 2,336 followers View post →
Sam Morkous, MD, FAAP, FAAN, FAASM, ABPN Diplomate
@samehserry20 · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 25, 2023 · 12 shares · 1,560 followers View post →
José Silva Figueroa
@josesilvaf · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 22, 2023 · 12 shares · 4,224 followers View post →
American Academy of Sleep Medicine
@AASMorg · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 22, 2023 · 12 shares · 25,898 followers View post →
PolicyKeys
@PolicyKey · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 21, 2023 · 12 shares · 97 followers View post →
STL Astro Society
@stlastro · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 21, 2023 · 12 shares · 188 followers View post →
robert b mack
@robertbmack2 · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 3,159 followers View post →
fern perkins MEd,BSc,DipEd.
@ftvictoriafern · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 918 followers View post →
Jean Wilkinson
@jeanmaireAK · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 1,493 followers View post →
Karin Johnson
@drsleepykarin · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 2,336 followers View post →
EvilLangBuildsMc
@lang_evil · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 478 followers View post →
John Hogenesch
@jbhclock · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 2,991 followers View post →
Conny Bergé
@BergeConny · X

RT @SaveStandard: Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange…

Aug 20, 2023 · 12 shares · 845 followers View post →
Save Standard Time
@SaveStandard · X

Standard Time aligns clocks more closely to circadian rhythms than Daylight Saving Time. Watch more #ScienceOfClockChange: https://t.co/AAFVtEa9PS https://t.co/C3CilBFbRE

Aug 20, 2023 · 34 likes · 12 shares · 12,907 followers View post →
Yuki_Shira
@YukiShiratori1 · X

https://t.co/UIAWS1BVHv https://t.co/5Lw4m5E3d7

Jul 15, 2023 · 1,636 followers View post →
Suzy Turby
@SaintCityDigest · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 11, 2023 · 11 shares · 720 followers View post →
Jay Pea
@mr_jay_pea · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 9, 2023 · 11 shares · 2,705 followers View post →
Save Standard Time
@SaveStandard · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 8, 2023 · 11 shares · 12,907 followers View post →
Lisa M Curtis
@lm2curtis · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 7, 2023 · 11 shares · 457 followers View post →
Laura
@LauraBundesen · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 6, 2023 · 11 shares · 3,789 followers View post →
EvilLangBuildsMc
@lang_evil · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 6, 2023 · 11 shares · 478 followers View post →
Mariah Baughn MD
@mariahbaughn · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 6, 2023 · 11 shares · 815 followers View post →
robert b mack
@robertbmack2 · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 5, 2023 · 11 shares · 3,159 followers View post →
ronyogason
@ronyogason · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 5, 2023 · 11 shares · 911 followers View post →
Perf2k22 (Ed)
@Perf2k22 · X

RT @SaveStandard: Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performa…

May 5, 2023 · 11 shares · 1,683 followers View post →
Save Standard Time
@SaveStandard · X

Standard Time aligns to circadian rhythms better than Daylight Saving Time, for optimal sleep, mood, health, and performance. Watch our full video here: https://t.co/AAFVtEa9PS https://t.co/7Y46QpPxGu

May 5, 2023 · 28 likes · 11 shares · 12,907 followers View post →
Dog Sat On My Pizza
@DogSatOnMyPizza · X

@ClarkeMicah Unfortunately that is incomplete research. External stimuli such as electric lighting means that the body clock is actually 25.27 hours. It only moves close to 24 hours when there are no externalities. https://t.co/y5psXYn5Pi https://t.co/VWC7d9SiPV https://t.co/GVWJtGuMW7

Mar 26, 2023 · 35 followers View post →
Nano-Lit
@Nano_Lit · X

RT @drsleepykarin: Clock change is coming.Learn how some smart circadian researchers are finding out what harms DaylightSaving Time causes…

Feb 24, 2023 · 2 shares · 1,312 followers View post →
Tyrin H.
@itsmetyrinh · X

RT @drsleepykarin: Our body clocks help us anticipate what our body needs. Why make things harder. Choose Permanent #StandardTime to harn…

Feb 23, 2023 · 1 share · 825 followers View post →
Karin Johnson
@drsleepykarin · X

Our body clocks help us anticipate what our body needs. Why make things harder. Choose Permanent #StandardTime to harness the power of the sun! The Science of Clock Change 3: Understanding Circadian Rhythms https://t.co/dddqFFUhKB via @YouTube

Feb 23, 2023 · 5 likes · 1 share · 2,336 followers View post →
Tyrin H.
@itsmetyrinh · X

RT @drsleepykarin: Clock change is coming.Learn how some smart circadian researchers are finding out what harms DaylightSaving Time causes…

Feb 23, 2023 · 2 shares · 825 followers View post →
Karin Johnson
@drsleepykarin · X

Clock change is coming.Learn how some smart circadian researchers are finding out what harms DaylightSaving Time causes both in the short-term and the long-term #SaveStandard The Science of Clock Change 3: Understanding Circadian Rhythms https://t.co/dddqFFUhKB via @YouTube

Feb 23, 2023 · 6 likes · 2 shares · 2,336 followers View post →
Jay Christopher King
@JayCKing78 · X

@fancyadraw

Feb 20, 2023 · 4 likes · 12,859 followers View post →
Dr. Michelle Gumz
@MLGumz · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 6, 2023 · 14 shares · 1,724 followers View post →
Save Standard Time
@SaveStandard · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 6, 2023 · 14 shares · 12,907 followers View post →
Blythe Gryphon
@Blythe_Gryphon · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 6, 2023 · 14 shares · 4,195 followers View post →
Patti
@misspattih · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 4, 2023 · 14 shares · 910 followers View post →
Karen
@Karensk8ergirl · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 3, 2023 · 14 shares · 666 followers View post →
Save Standard Time
@SaveStandard · X

RT @itsmetyrinh: @SaveStandard @POTUS @AASMorg https://t.co/qZF7u1Sjno

Feb 3, 2023 · 1 share · 12,907 followers View post →
EvilLangBuildsMc
@lang_evil · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 3, 2023 · 14 shares · 478 followers View post →
Proud​
@PriceRip · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 1,240 followers View post →
STL Astro Society
@stlastro · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 188 followers View post →
TooMuchVacancy
@toomuchvacancy · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 23 followers View post →
Betty
@BettyBersig5 · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 842 followers View post →
Tyrin H.
@itsmetyrinh · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 825 followers View post →
Tyrin H.
@itsmetyrinh · X

@SaveStandard @POTUS @AASMorg https://t.co/qZF7u1Sjno

Feb 2, 2023 · 4 likes · 1 share · 825 followers View post →
Stacy
@sunraec · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 966 followers View post →
Kathryn Horsman
@kathrynhorsman · X

RT @SaveStandard: What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #End…

Feb 2, 2023 · 14 shares · 3,010 followers View post →
Save Standard Time
@SaveStandard · X

What are circadian rhythms, and how are they affected by permanent Daylight Saving Time and permanent Standard Time? #EndDST #SaveStandardTime #SleepHealth https://t.co/Iw1UFPZgXC

Feb 2, 2023 · 24 likes · 14 shares · 12,907 followers View post →
睡眠良くしたければケトジェニック!(低糖質&高脂質)|小林充典|睡眠歯科医療3000人・減量指導
@tolucky39 · X

参考文献 ヒトの体内時計 https://t.co/fXgninbKi2 Stability, precision, and near-24-hour period of the human circadian pacemaker:ヒトの概日リズムの安定性、正確性、24時間に近い周期性 https://t.co/0rg1GHxYCx

Jan 19, 2023 · 1,079 followers View post →
chicken1201_1
@chicken1201_1 · X

RT @springflower_22: 人間の概日リズム周期は平均24.18時間と示した論文。1999年のものだが今も引用される。24.18±0.4時間の範囲に被験者24人全員がおさまり個人間のばらつきは少ない。被験者を28時間周期で生活させる強制脱同調という手法で深部体温や…

Nov 17, 2022 · 3 shares · 492 followers View post →
睡眠リズム障害患者会 Rhythm & Sleep 旧公式アカウント
@RhythmAndSleepT · X

RT @springflower_22: 人間の概日リズム周期は平均24.18時間と示した論文。1999年のものだが今も引用される。24.18±0.4時間の範囲に被験者24人全員がおさまり個人間のばらつきは少ない。被験者を28時間周期で生活させる強制脱同調という手法で深部体温や…

Nov 17, 2022 · 3 shares · 887 followers View post →
yosuke t
@YOSUKE_T · X

RT @springflower_22: 人間の概日リズム周期は平均24.18時間と示した論文。1999年のものだが今も引用される。24.18±0.4時間の範囲に被験者24人全員がおさまり個人間のばらつきは少ない。被験者を28時間周期で生活させる強制脱同調という手法で深部体温や…

Nov 16, 2022 · 3 shares · 273 followers View post →
木花
@springflower_22 · X

待って、論文へのリンクがうまく貼られてない。もう1回やってみる。 https://t.co/XoPYKl7UFg

Nov 16, 2022 · 6 likes · 1,758 followers View post →
木花
@springflower_22 · X

人間の概日リズム周期は平均24.18時間と示した論文。1999年のものだが今も引用される。24.18±0.4時間の範囲に被験者24人全員がおさまり個人間のばらつきは少ない。被験者を28時間周期で生活させる強制脱同調という手法で深部体温やメラトニン分泌を測定した。 DOI: 10.1126/science.284.5423.2177

Nov 16, 2022 · 15 likes · 3 shares · 1,758 followers View post →
deBermingham Guitars
@brrsmit406 · X

Genetics of the human circadian clock and sleep homeostat - https://t.co/CZEtdUCf1I CA, et al. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science. 1999;284:2177–81. Google Scholar2.Stephan FK, Zucker I. Circadian rhythms in drinking behavio... https://t.co/izc0drkr1C

Aug 11, 2019 · 626 followers View post →