Physiological Mechanisms of Heat Acclimatisation and Thermoregulatory Efficiency in Professional Miners Exposed to Deep-Level Heat in Solid Mineral Mining Sites in Nasarawa State, North Central Nigeria

Background: Nigeria's emerging solid mineral mining sector employs thousands of workers in subsurface and surface environments characterised by high ambient temperatures and humidity. Deep-level heat exposure without adequate physiological acclimatisation constitutes a serious occupational hazard. The cellular and systemic mechanisms of heat acclimatisation, including plasma volume expansion, sweat rate adaptation, heat shock protein induction, and cardiovascular adjustments, have never been characterised in Nigerian miners. Objectives: This study aims to evaluate thermoregulatory physiology in professional miners across varying lengths of service at active solid mineral sites in Nasarawa State, characterising sweat rate, plasma volume changes, heat shock protein 70 and 90 expression in peripheral blood mononuclear cells, cardiovascular drift patterns, and core temperature dynamics during standardised heat stress testing at baseline and after a controlled 10-day progressive heat acclimatisation protocol. Methods: Sixty miners with less than two years of service and forty with more than five years will undergo standardised treadmill heat stress testing in a climate-controlled chamber at 40 degrees Celsius and 50 percent relative humidity. Core temperature will be monitored by telemetric capsule. Plasma volume changes will be assessed by haematocrit and haemoglobin methods. Heat shock protein expression will be quantified by flow cytometry. Mixed-model ANOVA will examine acclimatisation time-course and service-length interactions. Expected Outcomes: Experienced miners are anticipated to demonstrate superior thermoregulatory efficiency with higher sweat rates, lower core temperature peaks, and greater baseline heat shock protein expression, reflecting occupational acclimatisation. Conclusion: This study will produce foundational heat physiology data to inform occupational safety standards for Nigeria's growing mining sector. Keywords: heat acclimatisation, thermoregulation, heat shock proteins, miners, Nasarawa.