How does your heart rate change during rem?

Pulse rate rises: Rem sleep -rapid eye movement sleep is the portion of a night's sleep when the eye is rapidly moving and most dreams occur. Several studies have shown that humans require a certain amount of REM sleep, often characterized as a percent of sleep to provide a restorative and healthy sleep.

Decreased: Heart rate is usually slow in rem.

Increased: Rem sleep is actually associated with surges in heart rate and an increase "sympathetic tone." physiologically, REM sleep is stressful with an increase in cerebral blood flow as well. Non-rem sleep is characterized by slowing heart rate and decreased cerebral blood flow. You dream in most all stages of sleep but REM dreams are more vivid and we usually remember them.