Kapalbhati is a part of Pranayam kriya where one forcefully exhales rapidly and in short bursts. Practitioners claim that it helps in cleaning lungs and in exercising the abdomen muscles. It is, therefore, recommended for reducing tummy fat.
The word Kapalbhati means skull illumination. Yogis claim that practicing it cleans the brain and gives a shining quality to a person's appearance. Modern science may give credence to this claim.
Researchers have known since 1941 that nanoparticles (10-30 nanometers which are almost 10-20 times smaller than those emitted in cigarette smoke), can directly reach the brain by breathing through the nose and bypassing the blood-brain-barrier (BBB).
However, this field of research remained dormant till the 1990s when scientists, alarmed by rising environmental pollution, revisited the early research and started discovering the harmful effects of toxin invasion of brain through breathing.
Today, rapidly growing research shows that a small part of the polluted air we breathe through our nostrils goes directly to the brain via the olfactory lobes (this is the area which gives us the sense of smell) and the rest (major portion) goes to the lungs supplying the necessary oxygen to the blood. Thus the action of inhaling affects both the mind and the body directly.
Medical researchers have also shown that though the pollutants are most of the times flushed out of the lungs by the body's immune system the toxic particles in the brain go on accumulating.
This has alarming implications for modern living since the inhaled pollution from household and automobile smoke, dust and general industrial environment has the ability to directly affect the nervous system. Recently scientists have shown that incidences of increased cancer, dementia, Alzheimer's disease, etc., have been attributed partly to the toxin invasion of the brain caused by these pollutants.
There are, however, indications that some of these small particles might be flushed out by the cerebrospinal fluid which floods the brain. During dreaming episodes, this flushing mechanism is very active. However, not all the particles leave the brain and hence affect the brain functioning.
Since these small particles go into the brain through the olfactory lobe it is quite possible that they could be flushed out by the forceful exhalation of the Kapalbhati process. This follows the principle of equivalence.
The forceful exhalation creates a venturi effect in the nasal passage thereby creating a partial vacuum which might suck out these particles from the olfactory lobes. Natural designs are very efficient and take into account all paths and forces. Thus the forceful exhalation of breath not only exercises the abdomen muscles but also cleans the lungs and the brain. This cleaning of toxins from the brain is the true meaning of Kapalbhati.
For people living in the present polluted atmosphere a good strategy would be to wear a nose mask which filters out the pollutants during outdoor activities and practice Kapalbhati daily to remove the particles which inadvertently might have gone into the system.
Naturally it is preferable if we reduce the pollution in our cities so that the air becomes clean. Then the loading of brain with pollutants can be drastically reduced.