This simple but powerful exercise releases tension in the upper body, stimulates the heart and assists with concentration. It is adapted from Kundalini Yoga practice.
Disclaimer: As with any physical movement there is a risk of injury. If you experience pain or discomfort adjust your posture or stop to prevent injury. You affirm your responsibility in practice.
Sit comfortably either on the floor in easy pose (cross-legged) or sit in a chair
Interlock the fingers of both hands in bear grip (curl your fingers and interlink them with the curled fingers of the other hand). The back of the left hand facing toward the chest (arm gently twisted toward you), the right hand facing outwards (see image below)
Ensure your forearms are parallel, at chest level and your shoulders are softly down
As you breathe IN through your nose, pull your fingers apart with maximum effort, as though you are trying to pry them apart - without actually allowing them to separate (you might shake as you do this). Breathe deeply, long and pause, holding the breath at the end, just for a few moments
As you breathe OUT, let go of tension in your hands, shoulders, and whole body whilst maintaining the posture, keeping your fingers gently interlocked. Breathe out slowly, deeply and pause at the end, just for a few moments
Place your focus on the feeling in your body and sound of the breath as you do this
Take 5-10 breaths this way, until you experience a tension release in the upper body and a calmer state of mind and body