Those who limit healthy carbohydrates for a prolonged period have been shown to demonstrate mental lethargy and increased general fatigue as the first symptoms.
It amazes me how little attention the value of balanced pH has garnered from the mainstream medical world. Positive acid/alkaline balance is one of the most important factors in athletic performance.
As a professional endurance athlete I have had to learn to deal with high levels of stress. Not just mental stress from competition, but also extreme physical stress from training over 30 hours a week.
Building strength to improve running efficiency. A few decades ago endurance athletes where encouraged to avoid gym training for fear that they would develop heavy, bulky muscles. The reasoning was: extra mass without function will inhibit endurance performance.