One challenge when training an athlete for optimal performance is to apply the correct amount of stress during training, that will result in the appropriate sport specific adaptations during recovery. An imbalance between training and recovery, this referred to as overtraining. And you've seen how a chronic imbalance between training and recovery is associated with Chronic Fatigue. Chronic Fatigue is due to the inability of the body to return itself to homeostasis and this leads to serious Health Consequences. It's time now to examine what happens to the athletes heart rate when homeostasis is not restored during the allocated recovery. Heart rate provides clues about an athlete's recovery status. And in this way, it's an indicator of possible overtraining. Now the terms overtraining and overtraining syndrome are often used interchangeably to describe a training recovery imbalance. However they refer to very different phenomenon. The term overtraining refers to an ongoing training load from which the athlete does not easily recover, within a reasonable time frame, and performance will decline. Overtraining Syndrome refers to the point where observable health symptoms occur, reflecting maladaptation to training stressors. This is the point where Chronic Fatigue, resulting from the ongoing disturbance of homeostasis, has taken a physiological toll on the athletes health. When symptoms appear, the damage to the athlete's health has already started to take place. The two extremes of the training load continuum are easily distinguished. On one end, is the training and recovery, is the point where training and recovery are well balanced and the athlete retains good health. And the other is maladaptation where training and recovery are so out of balance the athlete's health is negatively affected. You have good health from one side and poor health from the other side. And in between these two extremes is over-reaching and there is no really clear dividing point between what is a useful training recovery and balance and what is not useful. Recovery time is a marker of when the training stress has been too high. Acute overload is the stress imposed in one training session with a recovery that permits homeostasis to return to normal within around 24 hours or so. And this is equivalent to Selye's alarm phase. And fatigue is quickly dissipated when the training stress or training stimulus is removed. Over-reaching does not permit homeostasis to recover within 24 hours. And as you recall there are two types of over-reaching. Functional over-reaching is done strategically within a training cycle and recovery is possible within a few days. Recovery takes much longer for non-functional over-reaching and for this reason has no use training purpose. Early functional over-reaching does not show severe negative health symptoms beyond chronic fatigue. But the non-functional over-reaching may show the endocrine disturbances when you look at the blood tests. The psychological disturbances will also be fairly obvious. Overtraining syndrome refers to maladaptation to chronic fatigue, and serious health symptoms begin to appear. It is Hans Selye exhaustion phase, and it can take months for the athlete to recover. Now here is the super compensation curve that you're used to. The training effect or Supercompensation effect is due to successful adaptation resulting in a new level of performance. When functional over-reaching occurs, the training stimulus is applied before Supercompensation, and here the training stimulus had been applied before homeostasis has been reached as well. Non-functional over-reaching typically occurs when functional over-reaching has been allowed to continue for way too many days. Recovery takes too long and there is no useful training purpose with non-functional over-reaching. In this lesson we're going to discuss how to gauge the depth of the athlete's chronic fatigue from their heart rate. We're going to place functional over-reaching and non-functional over-reaching into the context of polyvagal theory. To explain the variation in heart rate when we suspect that the athlete is over trained. We're going to discuss the psychological difference between sympathetic overtraining and parasympathetic overtraining. And we'll end this lesson with a review of the European Task Force recommendations about overtraining in athletes. Let's get started.