Which of the following factors does NOT influence the effects of heat on a body?

The factor that does not influence the effects of heat on a body is the time of day. The physiological responses to heat are primarily influenced by the body's internal characteristics and external environmental factors. Body composition, age, weight, and height are all factors that can directly alter how the body interacts with heat.

Body composition affects thermal regulation; for example, individuals with higher fat content may retain heat differently than leaner individuals. Age can influence thermoregulation as well, with younger and older individuals experiencing heat differently due to metabolic changes. Weight and height impact the surface area to volume ratio, influencing how heat is absorbed or dissipated. In contrast, the time of day does not have a direct physiological impact on how the body responds to heat, even though it may affect environmental temperature. Thus, it is not a relevant factor when considering the effects of heat on the body.