When I was leading fire teams, one of the greatest safety issues we faced on a regular basis was Cumulative Fatigue. When we ask our bodies to perform at a high level with no break day after day, before long the effects begin to show physically, mentally and emotionally. Physically, our ability to respond decreases. What might have been easy a week ago, now seems difficult. Our immune system is weakened and even our sleep is effected. Extensive physical training without regular recovery breaks had been directly linked to stress fractures and other injuries. Mentally, cumulative fatigue causes our thought processes to be slowed and making us prone to poor decisions or an inability to make important decisions as quickly as necessary. Emotionally, we are more likely to blow up over a small slight or say something we will later regret.