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Sleep patterns of European expatriates in a dry tropical climate
Author(s) -
MONTMAYEUR ALAIN,
BUGUET ALAIN
Publication year - 1992
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/j.1365-2869.1992.tb00037.x
Subject(s) - sleep (system call) , tropical climate , climatology , psychology , environmental science , geography , geology , computer science , operating system , archaeology
SUMMARY Night sleep in sedentary African subjects living in the sahelian zone lasts from 7 h to 8 h, with high amounts of slow‐wave sleep (SWS) and paradoxical sleep (PS), SWS being present in each sleep cycle. We report here on sleep patterns in 6 healthy male European expatriates (aged 32–39 years) living in the same tropical climate. Polysomnography was taken for 3 consecutive nights in February (mean ambient temperature, T a : 29.5°C), March ( T a : 31.6°C) and May ( T a : 33.3°C). Comparisons between seasons were made with an analysis of variance, with P ≥ 0.05. Because of a first night effect, the first nocturnal recording was discarded. Total sleep time (TST) increased in May vs February and March ( P <0.05). Stage 2 was shorter in March than in February ( P < 0.001) and its proportion decreased from February to March ( P <0.02) and from March to May ( P <0.05). Conversely, SWS increased from February to March and March to May (duration, P < 0.001; proportion, P <0.05), due to an augmentation in stage 4 with more numerous and longer stage 4 phases. Stage 3 was also increased in May vs March. The latency to SWS was shorter in March. SWS was present in each sleep cycle. PS was high, but did not vary. The sleep pattern changes were directly correlated with T a . In conclusion, Caucasians living in the tropics slept similarly to Africans. The seasonal sleep variations favour the hypothesis that SWS is increased when thermoregulatory processes are triggered, either through passive climatic heating or exercise‐induced hyperthermia.