
> Invincible: How we can train our hearts to beat stress and achieve success
> The Healing Power of the Breath: Simple Techniques to Reduce Stress and Anxiety, Enhance Concentration, and Balance Your Emotions
One book I particularly recommend is “the healing power of the breath” , the exercise is very simple, basically just establishing a rhythm that works for your body type, and then you are good to go.
Thats not to say there’s not value into the pranayamas (breathing exercises) of yoga, but for pure efficacy just establishing a good rhythm is actually easy to learn and use.