Cardiovascular Responses and Oxidative-Stress Biomarkers among Bakery Workers Exposed to Indoor Heat in Kano, Nigeria

Background: Bakery workers in Kano State, Nigeria, are routinely exposed to intense heat generated by continuous oven use in poorly ventilated environments. Occupational heat exposure may impose cardiovascular and thermoregulatory strain and influence redox balance. However, locally relevant evidence on acute physiological and oxidative responses among bakery workers in northern Nigeria remains limited. Methods: A cross-sectional study was conducted among 50 adult male bakery workers recruited from selected bakeries in Kano metropolis. Cardiovascular parameters and body temperature were assessed before work and during peak exposure following one hour of routine bakery work. Participants were categorized into four age groups: 18–20, 21–25, 26–30, and >30 years. Serum malondialdehyde (MDA) and reduced glutathione (GSH) were assessed in a subsample of 15 bakery workers and 15 controls. Results: During peak bakery-work exposure, significant increases were observed in heart rate (74 [61 – 103] to 85 [68 – 109], p =0.001), systolic blood pressure (SBP, 128[80 – 180] to 130.5[97 – 190], p = 0.002), and body temperature (35.30 [34.5 –36.4 to 36.60 [35.0 – 37.7], p = 0.001), with a significant decrease in diastolic blood pressure (82 [61–100] to 81 [65 – 110], p = 0.004). Above 30-year age group showed significant within-group increase in all four parameters (SBD, DBP, HR and body temperature). Among the biochemical subsample, serum GSH was significantly higher in bakery workers than in controls (p = 0.002), whereas MDA showed a non-significant trend towards higher levels (p = 0.152).