The Buteyko method is not widely supported in the medical community, in part due to the fact that research has not supported this theory that hyperventilation and hypocapnia causes disease, with one review noting that there is no convincing evidence to indicate that trying to change asthmatics' carbon dioxide level is either "desirable or achievable." Studies that have looked for evidence to corroborate this theory, such as looking at the carbon dioxide levels in practitioners of Buteyko, have not found this evidence, leading some to propose alternate theoretical pathways for this method to improve symptoms.