Research on the relaxation response

The early laboratory work

The first studies measured people during transcendental meditation and found lower oxygen consumption, lower carbon dioxide output and slower breathing.^{[1] (source 1)} A 1974 paper described the same changes as a general state, the relaxation response, brought on by a quiet environment, a mental device, a passive attitude and a comfortable position.^{[2] (source 2)}

Clinical trials

A meta-analysis of 47 trials of meditation programs found moderate evidence of benefit for anxiety, depression and pain and no evidence that meditation was better than active treatments.^{[3] (source 3)} A review of mindfulness for chronic pain found small improvements in pain and in depression, with study quality varying.^{[4] (source 4)}

The American Heart Association concluded that meditation may be a reasonable adjunct to standard cardiovascular risk reduction, but evidence is not strong enough to replace other treatment.^{[5] (source 5)}

Biological studies

Research groups have also measured gene activity in long-term practitioners of the relaxation response. One study found differences in pathways involved in energy metabolism, insulin secretion and inflammation, although the sample was small and it does not show that these changes improve health.^{[6] (source 6)} Brain imaging after eight-week mindfulness courses has shown structural changes in a small group.^{[7] (source 7)}

What the research cannot tell us yet

• Many trials are small and last only weeks or months.
• It is hard to blind participants, so expectation may account for some of the benefit.
• People who choose to meditate may differ from those who do not.
• Results for one technique do not automatically apply to another.