When i wake up my bp is very low and feel dizzy? whats reason

Blood pressure.: Hello, as we sleep at night, our body goes into a rest mode where all our systems slow to rest. As you sleep your BP drops too. If you awaken suddenly and stand upright, your body needs to shift back into a functioning mode. The blood pools in our legs and abdomen so there is a temporary shift in blood flow away from the brain. We sense this as dizziness. This should pass within a few seconds.