Unless you have received special training, like Air Force fighter pilots, this cardiac coherence exercise is very difficult to do without a breathing guide! Giving Caesar his due, the breathing exercises of Sophrology are themselves inspired by Yoga Pranayama. Here are the 4 reasons why Dodow is not just a simple Sophrology breathing exercise: 1. Dodow indicates an optimal pace for you: 6 breaths per minute to put you in a state of rest and to rebalance your autonomic nervous system. Every breath out is 50% longer than the breath in to tire you out. Trying to follow your own breathing independently forces you to think and to count, which causes performance anxiety, thereby significantly delaying sleep. 2. The attention span of a person not used to meditating is thirty seconds at most, so you can very quickly become lost in your thoughts and forget to do the breathing exercise. Dodow's light signal keeps you on track! 3. Synchronizing one's breathing with a slow and steady light pulse has a hypnotic effect, similar to watching a pendulum that helps you unwind quickly 4. Dodow helps you simmer down and calm the flow of your thoughts by keeping your attention focused on an external point (the light signal), without your having to concentrate on your breathing - the emphasis is paradoxically placed on keeping you awake. We have no doubt as to the effectiveness of simple breathing exercises, but are less confident about the ability of our users to do them on their own ;).