Physiological and perceptual responses to temperature step changes between cold and hot environments

Abstract

Objectives. This study explores the effects of temperature steps on thermal responses to understand abrupt temperature shifts faced by heat-exposed workers during winter. Methods. Three temperature step changes with three phases (S20: 20–40–20 °C, S30: 10–40–10 °C, S40: 0–40–0 °C) were conducted. Phase 1 took 30 min, phase 2 took 60 min and phase 3 took 40 min. Eleven participants remained sedentary throughout the experiment, and physiological responses, thermal perception and self-reported health symptoms were recorded. Results. In temperature up steps, steady skin temperature and sweating onset were delayed, and heart rate dropped by 10 bpm from S20 to S40. In temperature down steps to cold conditions, individuals transitioned from thermal comfort to discomfort and eventually cold strain. Blood pressure increased in temperature down steps, correlating with temperature step magnitudes. Thermal responses to temperature steps of equal magnitude but opposite directions were asymmetries, which weakened as step magnitude increased. Thermal perceptions responded faster than physiological changes after temperature steps, while self-reported health symptoms lagged behind physiological responses. Conclusions. These findings contribute to expanding basic data to understand the effects of temperature step magnitude and direction.

Keywords:

• cold and hot temperature; step magnitude; step direction; physiological responses; health symptoms

Acknowledgments

The authors would like to acknowledge the financial support from the Fundamental Research Funds for the Central Universities, International Cooperation Fund of Science and Technology Commission of Shanghai Municipality and Graduate Student Innovation Fund of Donghua University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support received from Fundamental Research Funds for the Central Universities [Grant No. 2232024G-08]; International Cooperation Fund of Science and Technology Commission of Shanghai Municipality [Grant No. 21130750100]; Graduate Student Innovation Fund of Donghua University [Grant No. CUSF-DH-D-2021059].