What affects blood circulation anyway?
1) The nervous system
In research from the Boston University School of Medicine, we know that the state of being erect (which occurs in both men and women) is a carefully orchestrated series of events controlled by the Central Nervous System (CNS). Any disturbance in the network of nerve pathways that connects the genitals and the CNS can lead to problems with erections.
But the integrity and function of the nerves is not the only factor that affects erections. Being in a constant state of stress known as fight or flight can also affect erections. During REM sleep (dreaming), sympathetic (fight or flight) neurons are turned off in the brain stem. This event is referred to as (Cont'd)