What is one of the effects of high humidity on human health?

High humidity has a significant impact on human health, particularly in relation to heat stress. When humidity levels are high, the body’s ability to cool itself through sweat evaporation becomes less effective. This inefficiency can lead to a rise in the body’s core temperature, which contributes to increased heat stress.

In humid conditions, the moisture in the air saturates the skin and sweat. As sweat does not evaporate as readily, the body struggles to dissipate heat, making individuals more susceptible to heat-related illnesses such as heat exhaustion or heat stroke. Therefore, high humidity exacerbates the effects of heat, leading to increased discomfort and potential health risks.

Considering the other choices, decreased respiratory function and reduced heat stress do not align with the physiological responses to high humidity. Similarly, lower blood pressure is not directly correlated with the effects of humidity in such conditions. Instead, the focus should remain on how high humidity compromises the body's thermoregulation, thereby leading to increased heat stress.