The first organ that develops in the womb is the heart. With all our science we still do not understand exactly what animates its beat. But we do know there is a mysterious force that animates life itself. If you sit quietly in nature you can feel that force. Call it what you will, but it is the life force that animates your heart, which in turn animates your body by flowing oxygenated blood through your veins.
When we are unhappy it seems to me that we are out of rhythm with the flow and beat of life itself. While this force continues to animate us, we put our attention on our thoughts about what has happened and what might happen. Placing our consciousness on these thoughts for too long begins to disconnect us from the life force, and often leads to high levels of stress causing heart attacks, sudden unnatural death, and all manner of illness. We stop dancing to the rhythm of life, which is always there, and our entire system starts to fall apart, as we unplug from our power source. It is a natural warning to get back to the dance of life.
So when you are feeling stressed, remember the life force is always present, bringing you and everything around you to life. It is creating a beautiful diverse array of creation. Do whatever helps you let go of the thinking that is creating your stress, and use your heart to tune yourself with the rhythm and flow of life itself. Let your heart become a tuning fork for the heart beat of life, and like a runner whose breathing and heartbeat synchronizes with the body, you will feel a surge of natural energy.