title: Evidence for daily and weekly rhythmicity but not lunar or seasonal rhythmicity of physical activity in a large cohort of individuals from five different countries.
abstract: BACKGROUND
  Biological rhythmicity has been extensively studied in animals for many decades. Although temporal patterns of physical activity have been identified in humans, no large-scale, multi-national study has been published, and no comparison has been attempted of the ubiquity of activity rhythms at different time scales (such as daily, weekly, monthly, and annual).
  
  
  METHODS
  Using individually worn actigraphy devices, physical activity of 2,328 individuals from five different countries (adults of African descent from Ghana, South Africa, Jamaica, Seychelles, and the United States) was measured for seven consecutive days at different times of the year.
  
  
  RESULTS
  Analysis for rhythmic patterns identified daily rhythmicity of physical activity in all five of the represented nationalities. Weekly rhythmicity was found in some, but not all, of the nationalities. No significant evidence of lunar rhythmicity or seasonal rhythmicity was found in any of the groups.
  
  
  CONCLUSIONS
  These findings extend previous small-scale observations of daily rhythmicity to a large cohort of individuals from around the world. The findings also confirm the existence of modest weekly rhythmicity but not lunar or seasonal rhythmicity in human activity. These differences in rhythm strength have implications for the management of health hazards of rhythm misalignment.
authors.affiliation: a Circadian Rhythm Laboratory, Department of Psychology , Boise State University , Boise , Idaho , USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Refinetti
authors.affiliation: a Circadian Rhythm Laboratory, Department of Psychology , Boise State University , Boise , Idaho , USA.|b MRU Biomonitoring and Environmental Toxicology, Department of Biology, Faculty of Sciences and Techniques of Maradi , Maradi , Niger.
authors.forename: Mamane
authors.initials: M
authors.lastname: Sani
authors.affiliation: c Division of Internal Medicine, Center for Healthful Behavior Change , New York University Medical Center , New York , New York , USA.
authors.forename: Girardin
authors.initials: G
authors.lastname: Jean-Louis
authors.affiliation: c Division of Internal Medicine, Center for Healthful Behavior Change , New York University Medical Center , New York , New York , USA.
authors.forename: Seithikurippu R
authors.initials: SR
authors.lastname: Pandi-Perumal
authors.affiliation: d Stritch School of Medicine , Loyola University Chicago , Maywood , Illinois , USA.
authors.forename: Ramon A
authors.initials: RA
authors.lastname: Durazo-Arvizu
authors.affiliation: d Stritch School of Medicine , Loyola University Chicago , Maywood , Illinois , USA.
authors.forename: Lara R
authors.initials: LR
authors.lastname: Dugas
authors.affiliation: d Stritch School of Medicine , Loyola University Chicago , Maywood , Illinois , USA.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kafensztok
authors.affiliation: e Institute of Social and Preventive Medicine, Lausanne University Hospital , Lausanne , Switzerland.|f Ministry of Health , Mont Fleuri , Republic of Seychelles.
authors.forename: Pascal
authors.initials: P
authors.lastname: Bovet
authors.affiliation: g Tropical Medicine Research Institute, University of the West Indies , Mona , Kingston , Jamaica.
authors.forename: Terrence E
authors.initials: TE
authors.lastname: Forrester
authors.affiliation: h Research Unit for Exercise Science and Sports Medicine, University of Cape Town , Cape Town , South Africa.
authors.forename: Estelle V
authors.initials: EV
authors.lastname: Lambert
authors.affiliation: i School of Medical Sciences , Kwame Nkrumah University of Science and Technology , Kumasi , Ghana.
authors.forename: Jacob
authors.initials: J
authors.lastname: Plange-Rhule
authors.affiliation: d Stritch School of Medicine , Loyola University Chicago , Maywood , Illinois , USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Luke
mesh_terms: D056044:Actigraphy / Q000379:methods; D000328:Adult; D044383:Black People; D002940:Circadian Rhythm / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016081:Moon; D009043:Motor Activity / Q000502:physiology*; D012621:Seasons; D013997:Time Factors
keywords: Actigraphy; annual rhythm; circadian rhythm; physical activity; weekly rhythm