Spinal twists have a profoundly calming effect on the digestive system as they allow excess toxins known as ama (which are produced and stored in abdominal organs) to be flushed out.  Spinal twists help improve digestion and appetite by stimulating the digestive fire;   they combat constipation and improve sluggish organs. 

• Ardha Matsyendrasana is medically proven to provide benefits in cases of diabetes mellitus.  It is thought that by directly stimulating the pancreas, insulin may be released which may offer relief in some severe cases of diabetes mellitus.
• Twists help relieve backaches and headaches, sciatica and fatique and restore flexibility to the neck and shoulder area bringing welcome relief to many computer operators;

• Twists help with conception and counter infertility;
• Twists relieve menstrual discomfort;
• Twists provide relief to asthma;
• Twists energize, tone and rejuvenate the whole body.
• Twists greatly reduce stress and tension held in the spine, hips and legs and in other parts of the body;
• Twists result in an increase of motion and flexibility which enhance our sense of well-being and the overall lightness of the body;

Energetic (pranic) benefits:

Ardha Matsyendrasana increases prana, vitality and vigour and is known to be a destroyer of many deadly diseases due to the stimulation of the thymus gland in the chest (part of the immune system).

Ardha Matsyendrasana is a 4th chakra or heart chakra posture (Anahata in Sanskrit - anahata meaning unstruck).  This chakra integrates the more physical world below and the spiritual world above and makes us become one with life itself.   Anahata chakra is traditionally pictured as a 12-petalled green flower embodying 12 vrittis or modifications of the mind (hope, care, lust, duplicity, indecision, repentance, langour, impartiality, arrogance, incompetence, discrimination and defiance).

Anahata chakra is the seat of balance within the body.  We are no longer attached to the pleasures of this world.  When balanced, this chakra opens us to compassion and love, first to love of ourselves and then to selflessness and universal love.  Kalpataru, the “wish-fulfilling tree” is said to be located at the heart centre.  Kalpataru is the heavenly tree that will make our wishes come true if we stand beneath it.
The element of the heart chakra is air and its vayu is prana, the ascending force which governs the heart and lungs. 

• Twists balance vata by pushing energy back down into the base of the trunk, twists help soothe and slow down the vata energy. 
• The coolness provided by the twists help temper the fiery nature of the pitta
  energy.
• Twists open the chest and benefit the kapha energy .
• Twists awaken kundalini (serpent power) and stabilize lunar power (chandranadi).   Practicing Ardha Matsyendrasana prevents the mixing of the cool ambrosial nectar with the digestive fire. 

Mental benefits:
The spine is integral to our physical balance.  Twists enable us to take our awareness deep into the sensation of the spinal muscles and in the spine.  They enable us to observe the energy or space surrounding the body and the meeting point of our inner and our outer world.

It is not uncommon to experience resistance (and also queasiness) at times as the impurities are being squeezed out and the energetic pathways opened.  Twists bring up to the surface all sorts of pent-up emotions.  We may feel angry, bored, annoyed, uncomfortable, frustrated or indifferent and ready to come out of the posture as we begin to experience the purifying heat of the posture raising our body’s temperature.  Twists make us confront certain dark places within ourselves that we’d rather forget about and will put us in touch with some parts we are unaware of.  The mind will always look for ways to avoid going into these places.  So as soon as you are aware that it has drifted off, gently bring it back to your breath and see what happens.  Stay in the pose, attentive to the moment.  The attitude you bring to the posture is just as important as the posture itself.  Self-awareness is the key to emotional balance.   Let our imperfections be our teachers.

Twists are cooling postures (langana), beneficial for the body and the mind.  Impurities are expelled from the cells each time you exhale.

Twists have also a calming effect on the whole nervous system.  Twists help us develop focus, internal awareness, give us a sense of being grounded and teach us patience and humility.  Twists affect us not only physically, but also physiologically, energetically,  emotionally and mentally.  Twists are a constant reminder that we must transcend the limits of the ego and not be obsessed with wringing the body further and deeper at all costs and be happy to be where we are at this very moment.   We all too often tend to forget to enjoy the journey because we are so goal-driven and so desperate to attain what we wrongly perceive to be the ultimate pose.  Twists teach us that it is wrong to sacrifice the breath to go deeper into a posture.