More on HeartMath

Research shows the following consequences of unhealthy emotions:

Less ability to think clearly
Less efficiency in decision making
Less ability to communicate clearly
Reduced physical coordination
Higher risk of heart disease
Higher risk of high blood pressure 

With practise, you can learn how to generate positive emotions for yourself.
Research shows the following consequences of healthy or positive emotions:

Improved performance and achievement
More creativity and innovative problem solving
Better decision making
More flexibility in the way you think
Improved memory
Improved immunity to disease
Improved hormonal balance
Longer life span (HeartMath)

When we tend to belly breathe through the heart center and generate a positive feeling, we can change the signals the heart sends to the brain, influencing the Brian's perception and improves how we feel.
Information in the brain is also regulated by the thalamus. One of its roles is to distribute incoming sensory information to different parts of the brain and to see that they are synchronized. When the information coming into the thalamus is in keeping with a jagged signal, it interferes with the thalamus’ ability to do this job. Positive feelings, however, give way to smooth signals to the brain improving the brain's ability to process information. This helps with cognitive processing of information and making good decisions as well as improving the brain's functioning for coordination and speed.