Summary
Seven volunteers (3 females and 4 males; 3 Caucasians and 4 Africans) participated in two 24 h sessions during the cool dry (CD) and the hot dry (HD) seasons of the sahelian tropical climate. Body temperatures were taken on portable cassette recorders for 24 h. Rectal (T re) and mean skin (¯T sk) temperatures decreased in the HD compared to the CD conditions, meeting one of the criteria for adaptation to heat. No ethnic differences in thermal responses were found. Males and females differed in their body temperature rhythms and in their reactions to heat. Body temperatures were higher in females than in males. Males reacted to heat with a decrease in T re, without change in the T re-¯T sk gradient. Females showed a decrease in both T re and ¯T sk, more marked for ¯T sk, with an increase in the T re-¯T sk gradient. It was concluded that males showed seasonal acclimatization to heat via a decrease in metabolism confirmed by a decrease in plasma levels of thyroid stimulating hormone (TSH) in the HD condition. Females showed a mixed metabolic and thermolytic type of acclimatization, with an absence of variation in plasma TSH levels. In conclusion, the steady rise in temperature between the CD and HD conditions was sufficient to trigger an acclimatization to heat similar in Caucasian and African subjects, although exposure to the external climate differed widely.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Berg GR, Utiger RD, Schalch DS, Reichlin S (1966) Effect of central cooling in man on pituitary thyroid function and growth hormone secretion. J Appl Physiol 21:1791–1794
Berger RJ, Palca JW, Walker JM (1985) Human sleep, metabolism, and thermoregulation during cold-exposure. In: Koella WP, Rüther E, Schulz H (eds). Sleep '84. Gustav Fisher Verlag, Stuttgart-New York, pp 77–80
Bittel J, Hénane R (1975) Comparison of thermal exchanges in men and women under neutral and hot conditions. J Physiol (Lond) 250:475–489
Bligh J (1984) Regulation of body temperature in man and other mammals. In: Shitzer A, Eberhard RC (eds), Heat Transfer in Medicine and Biology, vol. 1. Plenum Publishing Corp, New York, pp 15–51
Buguet AGC, Livingstone SD, Reed LD, Limmer RE (1976) EEG patterns and body temperatures in man during sleep in Arctic winter nights. Int J Biometeor 20:61–69
Buguet A, Allin L, Dittmar A, Muzet A, Peyrin L, Roussel B (1983) Human reactions to chronic heat. Proc Int Union Physiol Sci 15:101
Chouvet G, Mouret J, Coindet J, Sifre M, Jouvet M (1974) Périodicité bicircadienne du cycle veille-sommeil dans les conditions hors du temps. Etude polygraphique. Electroencephalogr. Clin Neurophysiol 37:367–380
Colquhoun WP, Paine MWPH, Fort A (1978) Circadian rhythm of body temperature during prolonged undersea voyages. Aviat Space Environ Med 49:671–678
Commissariat à l'Energie Atomique. Office des Rayonnements Ionisants (1981) Dosage Radio-Immunologique de la T.S.H. Notice d'Utilisation de la Trousse Réf. TSHK-PR. International CIS, St-Quentin-Yvelines
Cunningham DJ, Stolwijk JAJ, Wenger CB (1978) Comparative thermoregulatory responses of resting men and women. J Appl Physiol 45:908–915
DuBois EF, Ebaugh FG, Hardy JD (1952) Basal heat production and elimination of thirteen normal women at temperatures from 22° C to 35° C. J Nutr 48:257–293
Fox RH, Lofstedt BE, Woodward PM, Eriksson E, Werkstrom B (1969) Comparison of thermoregulatory function in men and women. J Appl Physiol 26:444–453
Gati R (1986) Adaptation physiologique de l'homme soumis aux variations saisonnières du climat sahélien en période sèche (saison fraîche et saison chaude). Analyse circadienne des températures corporelles, de la sécrétion de l'hormone de stimulation thyroīdienne (TSH) et du sommeil. M.D. Thesis University of Niamey, Niamey, Niger
Goldstein-Golaire J, Vanhaelst L, Bruno OD, Leclercq R, Copinschi G (1970) Acute effects of cold on man. J Appl Physiol 29:622–626
Haslag WM, Hertzman AB (1965) Temperature regulation in young women. J Appl Physiol 20:1283–1288
Hénane R, Buguet A, Roussel B, Bittel J (1977) Variations in evaporation and body temperature during sleep in man. J Appl Physiol: Respirat Environ Exercise Physiol 42:50–55
Hershman JD, Read DG, Bailey AL, Normal VD, Gibson GB (1970) Effect of cold exposure on serum thyrotropin. J Clin Endocrinol 30:430–434
Hori S, Ihzuka H (1986) Comparison of physical characteristics, body temperature and resting metabolic rate at 30° C between subtropical and temperate natives. Int J Biometeor 30:115–122
Ihzuka H, Hori S, Akamatsu T (1986) Seasonal variations of physiological responses to heat of subtropical and temperate natives. Int J Biometeor 30:107–113
Kreider MB, Iampietro PF (1959) Oxygen consumption and body temperature during sleep in cold environments. J Appl Physiol 14:765–767
Mason ED, Jacob M (1972) Variations in metabolic rate responses to change between tropical and temperate climate. Human Biol 44:141–172
Mellette HC, Hutt BK, Askovitz SI, Horvath SM (1951) Diurnal variations in body temperatures. J Appl Physiol 3:665–675
Monk TH, Leng VC, Folkard S, Weitzman ED (1983) Circadian rhythms in subjective alertness and core body temperature. Chronobiologia 10:49–55
Moore-Ede MC, Lydic R, Czeisler CA, Tepper B, Fyller CA (1980) Characterization of separate circadian oscillators driving rest-activity and body temperature rhythms. Sleep Res 9:275
Munro AF (1950) Basal metabolic rates and physical fitness scores of British and Indian males in the tropics. J Physiol (Lond) 110:356–366
O'Malley BP, Richardson A, Cook N, Swart S, Rosenthal FD (1984) Circadian rhythms of serum thyrotrophin and body temperature in euthyroīd individuals and their responses to warming. Clin Sci 67:433–437
Tuomisto J, Mannistol P, Lambert BA, Linnoila M (1980) Effect of cold exposure on serum thyrotrophin levels in man. Acta Endocrinol 83:522–527
Valléry-Masson J, Boulière F, Poitrenaud J (1980) Can a protracted stay in the tropics permanently lower basal metabolic rates of European expatriates? Ann Human Biol 7:267–271
Wells CL (1980) Responses of physically active and acclimatized men and women to exercise in a desert environment. Med Sci Sport Exercise 12:9–13
Wilson D (1956) Adaptation (sic) of the basal metabolic rate of man to climate. A review. Metab Clin Exp 5:531–542
Wyndham CH (1969) Adaptation to heat and cold. Environ Res 2:442–469
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Buguet, A., Gati, R., Soubiran, G. et al. Seasonal changes in circadian rhythms of body temperatures in humans living in a dry tropical climate. Europ. J. Appl. Physiol. 58, 334–339 (1988). https://doi.org/10.1007/BF00417272
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00417272