From
Cure Yourself with Yoga
by Ac. Hiranmayananda Avt.

Halasana - The Plough

Benefits

As while doing this asana, one has to pass through Sarvaungasana. One gets almost all the benefits of Sarvaungasana. It strengthens the abdominal muscles and exercises all the vertebrae of the spine, stretching the whole spine and relieving lower back pain.

Halaasana can alleviate various type of neck pain, releasing any tension that may have accumulated in those areas. It is good for the liver and spleen and gives relief to those suffering from muscular rheumatism.

Halasnana tones up the entire body especially helping those with obesity. It is good for removing constipation and indigestion. The plough develops patience, memory and higher consciousness.

Step 1 : Lie down on the back and relax the entire body
Step 2 : Raise to the position of the all limbs posture with the leg extended in the air and the chin touching the chest.
Step 3 : Gradually bring the legs backwards and extend them as far as possible. Let the toes touch the ground, keeping the arms in  a prone position on either side of the body. Maintain this posture trying to feel the body's inner harmony.
The Plough posture can be practiced from thirty seconds up to five minutes. It is of great benefit for mental concentration, especially helping those who are overly extroverted to gain a good degree of introversion whilst at the same time calming the whole body and mind.

Apart from that it enlivens the different organs in the stomach area and helps to reduce the problem of lack of appetite, indigestion, belching. If one suffers from problems with gas, which cause acute pain in the abdomen, this posture can release the gas from the bowels and promotes a feeling of relaxation.

Caution
This asana should be avoided by those who suffer from heart and lung disorders.