What item may increase the risk of a heat-related illness?

The choice of using a swim cap or shower cap is linked to an increased risk of heat-related illnesses because these items can limit the evaporation of sweat from the scalp. Sweating is a crucial physiological response that helps regulate body temperature. When wearing a swim cap or shower cap, the ability of sweat to evaporate and cool the body is hindered, especially in warm environments. This can lead to overheating and potentially heat exhaustion or heat stroke, which are serious conditions associated with elevated body temperature and dehydration.

In contrast, the other options either do not substantially affect temperature regulation or actually promote cooling and hydration. Wearing a bathrobe is unlikely to contribute significantly since it is typically worn in cooler settings. Bringing cold water is beneficial and helps keep the body hydrated and cool, reducing the risk of heat-related ailments. Avoiding sunscreen does pose some risk of sunburn but does not directly relate to overheating acts like wearing items that restrict sweat evaporation.