BACKGROUND: Chronotype, phase preference to perform activities during a 24-hour day, represents distinct circadian temporal organization of living organisms. Morning and evening types can be identified by questionnaires such as Horne and Östberg (HO) and Munich Chronotype Questionnaire (MCTQ). Environmental factors, such as different light-dark cycles experienced at different latitudes, interact with the organisms' circadian timekeeping system. Therefore, chronotype is expected to vary as a result of different geographical locations. AIM: To identify differences in chronotype distribution in populations of two Brazilian cities, Natal and Sao Paulo, located at different latitudes. SUBJECTS AND METHODS: Two specific questionnaires, the Horne and Östberg Questionnaire (HO) and the Munich Chronotype Questionnaire (MCTQ), were used to identify chronotypes of undergraduate students from São Paulo and Natal. RESULTS: The comparison of the curve distributions of HO and MCTQ scores between both cities allowed one to observe that, while HO curves of São Paulo and Natal overlapped, MCTQ curves showed a clear shift towards eveningness in São Paulo. CONCLUSION: This experiment confirmed results from previous studies that the farther away from the equator, the longer the delay of the sleep phase. It was also concluded that MCTQ is better at detecting this phenomenon.
BACKGROUND: Chronotype, phase preference to perform activities during a 24-hour day, represents distinct circadian temporal organization of living organisms. Morning and evening types can be identified by questionnaires such as Horne and Östberg (HO) and Munich Chronotype Questionnaire (MCTQ). Environmental factors, such as different light-dark cycles experienced at different latitudes, interact with the organisms' circadian timekeeping system. Therefore, chronotype is expected to vary as a result of different geographical locations. AIM: To identify differences in chronotype distribution in populations of two Brazilian cities, Natal and Sao Paulo, located at different latitudes. SUBJECTS AND METHODS: Two specific questionnaires, the Horne and Östberg Questionnaire (HO) and the Munich Chronotype Questionnaire (MCTQ), were used to identify chronotypes of undergraduate students from São Paulo and Natal. RESULTS: The comparison of the curve distributions of HO and MCTQ scores between both cities allowed one to observe that, while HO curves of São Paulo and Natal overlapped, MCTQ curves showed a clear shift towards eveningness in São Paulo. CONCLUSION: This experiment confirmed results from previous studies that the farther away from the equator, the longer the delay of the sleep phase. It was also concluded that MCTQ is better at detecting this phenomenon.
Authors: Mamane Sani; Roberto Refinetti; Girardin Jean-Louis; S R Pandi-Perumal; Ramon A Durazo-Arvizu; Lara R Dugas; Ruth Kafensztok; Pascal Bovet; Terrence E Forrester; Estelle V Lambert; Jacob Plange-Rhule; Amy Luke Journal: Chronobiol Int Date: 2015-06-02 Impact factor: 2.877
Authors: Inge Kirchberger; Kathrin Wolf; Margit Heier; Bernhard Kuch; Wolfgang von Scheidt; Annette Peters; Christa Meisinger Journal: BMC Public Health Date: 2015-08-14 Impact factor: 3.295
Authors: Kate Porcheret; Lucien Wald; Lin Fritschi; Menno Gerkema; Marijke Gordijn; Martha Merrrow; Shantha M W Rajaratnam; Daniel Rock; Tracey L Sletten; Guy Warman; Katharina Wulff; Till Roenneberg; Russell G Foster Journal: Chronobiol Int Date: 2018-06-18 Impact factor: 2.877
Authors: Suzana Almoosawi; Snieguole Vingeliene; Frederic Gachon; Trudy Voortman; Luigi Palla; Jonathan D Johnston; Rob Martinus Van Dam; Christian Darimont; Leonidas G Karagounis Journal: Adv Nutr Date: 2019-01-01 Impact factor: 8.701