Sudden dizziness when you get up and sit up is considered benign positional vertigo, also known as otoliths. In normal people, there are two balance receptors, one in the left and one in the right inner ear. The otolith is located on the otolith apparatus, and when it is dislodged, it can stimulate dizziness, visual rotation, nausea, and vomiting during a specific position change. However, in otoliths, the dizziness and visual rotation usually do not last more than a minute, and they are short-lived and recover on their own. When you turn your head to the affected side, it may reappear, and it is a self-healing condition. Another thing to consider is postural hypotension, which is usually seen in elderly people who experience transient dizziness during sitting up, squatting, or getting up.