States of consciousness are the distinct awarenesses one has of the environment and oneself. These include deep sleep, light sleep, relaxation, meditation and alert awareness. In yoga or meditation practice, yogis may be able to alter their state of consciousness. The term, altered state of consciousness, is generally defined as “any state of awareness which is different from the normal waking consciousness.”
Switching between different states of consciousness has been found to be associated with switching to a different pattern of brain waves. These can be measured scientifically using an electroencephalograph to detect electrical activity in the brain.