The original research done on the Relaxation Response used people who practiced Transcendental Meditation. The Transcendental Meditation program recommended for people to meditate twice a day for 20 minutes each time. This was the protocol used in many of the original experiments on the Relaxation Response. These early experiments are the inspiration for the Simple Protocol. So, this is why the Simple Protocol suggests using 20 minutes for each period of bringing about the Relaxation Response.