Why Does Matt Walker Say Dream Sleep Shuts Serotonin Off?

Matt Walker says REM sleep is the only time in the 24-hour period when serotonin and noradrenaline, also called norepinephrine, shut off completely. Both must shut down to produce REM sleep. Serotonin is the same chemical as 5-HT. Acetylcholine ramps up to produce REM sleep. The three neuromodulators run a reciprocal push-pull that generates a natural architecture of sleep through the night.

Raising serotonin dramatically at night, and keeping that rise in place while REM sleep should start, could artificially fragment REM sleep. Matt Walker says he does not know the data and does not think anyone has really got good data. If the data arrived in two years, he would look first at disruption of REM sleep, non-REM sleep, and reciprocal regulation, because serotonin needs to be up at one time and down at another.

On the show, the host agrees and says he is personally never taking tryptophan or serotonin again unless a clinical reason requires it.