Breathing patterns are a big part of the Pilates technique. By breathing properly you can ease out short muscles and also improve your posture.  Just by using your breath, you can help to open up your rib cage and help to re-balance your upper body posture. Also, breathing deeply helps bring more oxygen into the body which not only allows the muscles to be given more fuel but also gives an individual a sense of calm.

A Pilates class should also be progressive. Week by week an individual can feel how they are improving and moving better. This gives you a great sense of achievement and even more body awareness.

The breathing exercises integral to Pilates promote good circulation, improve lung capacity and improve your all-round energy levels. Deep breathing increases the oxygen in your blood, helping to invigorate the mind, brain and body and help you forget any day-to-day cares.

The affects can last long after a Pilates session has ended, since Pilates strengthens the abdominal muscles and speeds up your metabolism. Pilates can improve your general health through finding a neutral position for your pelvis, spine and rib-cage, strengthening your core abdominal muscles and stabilising and mobilising your shoulders and neck.

All of these benefits should help leave you with a feeling of more energy.
A more relaxed person is a less stressed one, which tends to mean more energised.