You might benefit from learning deep, 3-part breathing to improve oxygenation in your circulatory system. This is the opposite of hyperventilation, or rapid or deep breathing, usually caused by anxiety or panic. This overbreathing may actually leave you feeling breathless. If you frequently overbreathe (sometimes referred to as hyperventilation syndrome), this may be triggered by ongoing emotions of stress, anxiety, depression, or anger.

You can find some tips and exercises here: relaxation techniques