Which of the following is a consequence of fatigue as an environmental risk factor?

Fatigue significantly impacts a person's physical and mental capabilities, leading to a higher susceptibility to cold injuries. When individuals are fatigued, their body's ability to regulate temperature and respond to the cold diminishes. This can result in a reduced awareness of environmental conditions and a slower reaction time to cold exposure, increasing the risk of conditions such as frostbite or hypothermia.

On the other hand, options like increased energy levels, improved focus, and enhanced physical performance are typically associated with alertness and well-being, which contrast with the effects of fatigue. Fatigue detracts from one's energy, mental clarity, and overall performance, making it a critical factor to consider in mountain warfare training and operations.