What can still happen during heat stroke that contradicts previous beliefs?

During heat stroke, one of the significant misconceptions is that high perspiration would always occur in conjunction with this condition. Traditionally, it was believed that a person suffering from heat stroke would exhibit heavy sweating due to overheating of the body. However, heat stroke can actually present with little to no sweating, especially in individuals who are unable to produce sweat, such as those who are dehydrated or have been heavily exerting themselves in extreme heat conditions.

This lack of sweating is due to thermoregulation failure, where the body's systems can no longer manage temperature effectively, leading to the dangerous rise in body temperature characteristic of heat stroke. Therefore, while rapid heartbeat, altered blood pressure, and seizures can occur during heat stroke, the notion that high perspiration is a reliable symptom contradicts the current understanding of how this serious condition can manifest, making it critical for rescuers and medical responders to recognize that decreased sweating can be a key indicator of heat stroke.