Which of these symptoms are clear signs of heat exhaustion?

The symptoms indicative of heat exhaustion include cool, pale, clammy skin and chills. This condition typically occurs when the body is unable to cool itself effectively during prolonged exposure to high temperatures, often exacerbated by physical exertion in hot weather. The presence of cool, clammy skin is a critical factor because it indicates that the body is still attempting to cool down through perspiration.

In heat exhaustion, the body may experience a significant loss of fluids and electrolytes, leading to symptoms like weakness and fatigue. The coolness of the skin, in contrast to heat stroke where skin can be hot and dry, is a distinctive characteristic of heat exhaustion. Chills may also occur due to the body’s reaction to the stress it is under, as it tries to regulate temperature.

Other symptoms such as thirst, rapid pulse, or hot flushed skin are indicative of dehydration and heat-related illnesses but are not the hallmark signs of heat exhaustion itself. The combination of clammy skin and the body's inability to adequately cool down is what truly defines this condition.