Abstract
Plasma thyroxine (T4), triiodothyronine (T3) and thyrotropin (TSH) levels were monitored in 10 healthy euthyroid male subjects of the age group 20 to 30 years before and during heat and cold acclimatisation schedule in a sequential manner. The subjects were exposed to 45‡C DB and 30% relative humidity in a hot chamber for 2 hours daily for 8 consecutive days. Subsequently they were exposed to cold for 4 hours daily at 10‡C for 21 days. The mean plasma T4 and T3 concentration before exposure to heat were 7.87±0.82 ug/dl and 159.8±9.1 ng/dl respectively. A significant decrease in both T4 (p<0.05) and T3 (p<0.01) levels to mean values of 6.4±0.76Μg/dl and 129±7.9 ng/dl was recorded on day 4 of exposure to heat. Further significant decrease (p<0.05) over the preceding T3 levels was observed on day 8 of heat exposure. Plasma T4 and T3 on day 21 of cold exposure was not significantly different from the levels reckoned after last day of heat exposure but was significantly lower than the pre-exposure values. Throughout the thermal stress schedule there was no change in the TSH levels. These observations suggest that a decrease in thyroid hormone levels during exposure to heat might be an adaptive process which continues even during cold acclimatisation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
BARBASHOVA, Z. I. (1967): Studies on the mechanism of resistance to hypoxia. A review. Int. J. Biometeorol., 11: 243–254.
CHOPRA, I. J., CHOPRA, U., SMITH, E. R., REZA, M. and SOLOMON, D. H. (1975): Reciprocal changes in serum concentration of 3, 3′, 5′-triiodothyronine (reverse T3) and 3, 3′, 5-triiodothyronine (T3) in systemic illnesses. J. Clin. Endocr. and Metab. 41: 1043–1049.
COLLINS, K. J. and WEINER, J. S. (1967): Endocrinological aspects of exposure to high environmental temperature. Phys. Rev. 48: 785–839.
EASTMAN, C. J., EKINS, R. P., LEITH, I. M. and WILLIAMS, E. S. (1974): Thyroid hormone response to prolonged cold exposure in man. J. Physiol. 241: 175–181.
FLEISCHNER, J. R. and SARGENT, F. II (1959): Effects of heat and cold on the albino rat: Crossed resistance or crossed sensitization? J. Appl. Physiol. 14: 789–797.
GOLDSTEIN-GOLAIRE, J., VANHAELST, L., BRUNO, C. D., LECTERCO, R. and COPINSCHI, G. (1970): Acute effects of cold on blood levels of growth hormone, cortisol and thyrotropin in man. J. Appl. Physiol. 29: 622–626.
GLASER, E. M. and SHEPHARD, R. J. (1963): Simultaneous experimental acclimatisation to heat and cold in man. J. Physiol. 169: 592–602.
HALE, H. B., WILLIAMS, E. W. and ELLIS, Jr., J. P. (1972): Cross adaptation in military trainees in a hot climate. Aerospace Med. 43: 978–983.
INGBAR, S. H. and BASS, D. E. (1967): The effect of prolonged exposure to cold on production and degradation of thyroid hormones in man. J. Endocr. 37, II-III.
O'CONNEL, M., ROBBINS, D. C., HORTON, E. E., SIMS, E. A. H. and DANFORTH, E. Jr. (1979): Changes in serum concentration of 3,3′-5-triiodothyronine and 3,5′, 3′-triiodothyronine during prolonged moderate exercise. J. Clin. Endocr. and Metab. 49: 242–246.
PICHAN, G., SRIDHARAN, K., SWAMY, Y. V., JOSEPH, SANTHA and GAUTAM, R. K. (1984): Physiological acclimatisation to heat after a spell of cold conditioning in tropical subjects. Aviat. Space. Environ. Med. (In press).
RAMANATHAN, N. L. (1964): A new weighting system for mean surface temperature of human body. J. Appl. Physiol. 19: 531–533.
RAUD, H. R. and ODELL, W. D. (1969): The radioimmunoassay of human thyrotropin. Brit. J. Hosp. Med. 2: 1366–1376.
SAWHNEY, R. C., MALHOTRA, A. S., MATHEW, LAZER and RAI, R. M. (1983): Alterations in thyroid gland function during cold exposure in man. Paper presented to International Congress on Biometeorology, New Delhi, India.
SELYE, H. (1950): The Physiology and Pathology of Exposure to Stress. Montreal, Acta, Incs.
TALWAR, K. K., SAWHNEY, R. C. and RASTOGI, G. K. (1977): Serum levels of thyrotropin, thyroid hormones and their responses to thyrotropin releasing hormone in infective febrile illnesses. J. Clin. Endocr. Metab. 44: 398–403.
WILSON, O., HEDNER, P., LAURELL, S., MOSSLIN, B., RERUP, C. and ROSENGREN, E. (1970): Thyroid and adrenal response to acute cold exposure in man. J. Appl. Physiol. 28: 543–548.
WOEBER, K. A. (1971): Alterations in thyroid hormone economy during acute infection with Diplococcus pneumoniae in the rhesus monkey. J. Clin. Invest. 50: 378–387.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sridharan, K., Sawhney, R.C., Mathew, L. et al. Thyroid gland function during cross adaptation to heat and cold in man. Int J Biometeorol 30, 223–230 (1986). https://doi.org/10.1007/BF02189465
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02189465