Introduction: Exposure to noise and heat individually causes some changes in the function of cardiovascular system in workplaces. This study was performed to find the effect of combined effect to heat and noise over systolic and diastolic types of blood pressure in experimentally controlled conditions.

Matherials & methods: This longitudinal study was done on 12 males in climatic chamber in 2014. Blood pressure including Systolic and diastolic ones were measured in the following condition 15 minutes after rest in exposure to heat (40℃, RH: 30%) exposure to noise with 75, 85 and 95 dB rates in thermal comfort condition (22/1 ± 0.9 WBGT) and combined exposure to heat (40℃, RH: 30%) and noise with 75, 85 and 95 dB. Friedman test was used to analyze the data.

Findings: The mean systolic and diastolic rate of blood pressure showed significant difference  before and after exposure to heat and noise with the mentioned  levels (P>0.001).

Discussion & Conclusions: At first, systolic and diastolic blood pressure increased at exposure to heat, but prolonged exposure decreased the values. Exposure to different levels of noise (75, 85 and 95 dB) especially beyond occupationally standardized levels (95dB) causes elevation of both types of blood pressure to heat and noise. However, subtle changes of blood pressure happened in combined effect to heat and noise actually, middle condition of exposure including every one of heat and noise individually.