A pilot study has found that experienced practitioners of yoga experience an increase in GABA levels in the brain after a yoga session.

Professor Perry Renshaw and his team studied eight experienced yoga practitioners and eleven comparison subjects. Using a specific type of MRI scan, they analysed GABA levels in the brains of study participants before and after a 60 minute session of either asana yoga (for the experienced practitioners) or reading (in the comparison group).

The researchers, from Boston University School of Medicine, McLean Hospital, and Harvard Medical School, USA, noted a 27% increase in GABA levels in the brains of the yoga group, but no change in GABA levels in the reading group.

This small study was published in the May edition of the Journal of Alternative and Complementary Medicine. It's not clear whether the effect on GABA levels in the brain derived from having had an hour's worth of exercise, or whether the meditative and breathing component of yoga was important. It's possible that the type of yoga practised made a difference too; as might the fact that the yoga group only included experienced practitioners: beginners might not experience the same effect.

No one in the study has epilepsy, and it's possible that the same study repeated with people who have epilepsy would not show the same results. However the fact that yoga can affect GABA levels may be part of the explanation for the beneficial effects of yoga on
epilepsy found by other studies.

Gamma-aminobutyric acid (GABA)
GABA is the main inhibitory neurotransmitter in the brain. When a molecule of GABA attaches itself to one of its specific receptors on the surface of a neurone, this inhibits the activity of the neurone. These inhibitory systems are the brakes in the brain; if they are not enough to balance excitatory activity, a seizure happens.

Some types of anti-epileptic medication, for example, vigabatrin and tiagabine, act to increase the amount of GABA present in the brain, or make more of it bind to its receptors. Diazepam, used for the emergency treatment of seizures, also binds to GABA receptors.

The relationship of GABA levels to epilepsy is not simple - it's not just a case of increasing levels of GABA to decrease the likelihood of seizures. (For conditions such as depression and anxiety disorders, the relationship is more direct.) This study should encourage further investigations of how yoga affects brain chemistry and how this might help people with epilepsy.

Read more about the study

Read more about epilepsy and GABA