Which of the following is a critical step in treating heat stroke?

Loosening the victim's clothing and equipment is indeed a critical step in treating heat stroke. This action facilitates the body's natural cooling processes by allowing heat to dissipate more efficiently. When clothing and equipment are too tight or heavy, they can trap heat against the body, exacerbating the condition and potentially leading to more severe complications.

In cases of heat stroke, rapid cooling of the body is essential for reducing the risk of serious health consequences. This can be best achieved by providing the body with an opportunity to release heat, hence loosening attire is a foundational step in immediate care.

Additionally, while providing cold drinks and moving the victim to an isolated area may seem beneficial, they are not as critical in the immediate response to heat stroke. Cold drinks can sometimes lead to complications if the person is disoriented or unable to swallow safely. Isolating the victim, although it may help provide a calm environment, does not actively contribute to lowering body temperature. Using blankets to warm the victim counteracts the urgency of cooling a person suffering from heat stroke, which is essential for recovery.