Dizziness after standing for long periods: what to know

When you stand still, the leg muscles do less to help return blood to the heart. Blood can collect in the lower body, and the brain may briefly receive less blood, causing lightheadedness, blurred vision, weakness or a need to sit. Heat, dehydration, illness, some medicines and low blood count can make this response stronger.

Spinning with head movement is a different sensation and can suggest a balance-organ cause. Repeated episodes, especially without an obvious trigger, deserve a clinical review rather than self-diagnosis.

At the first warning, cross your legs or tense your leg muscles if you can do so safely, then sit or lie down. Rise in stages, move your ankles during long waits, keep cool and drink regularly unless a clinician has restricted fluids. Avoid locking your knees, and do not climb, drive or continue standing while symptoms remain.

Seek emergency help for fainting with injury, chest pain, severe breathlessness, confusion, a new weakness or speech problem, or a sustained fast or irregular heartbeat. Arrange prompt advice if episodes are frequent, last longer than expected, occur during activity, or come with black stools, unusually heavy bleeding or marked fatigue.

Ask whether your medicines, blood pressure, hydration, heart rhythm or blood count should be reviewed. Record the setting, standing time, heat, meals, fluid intake, posture, associated palpitations and whether sitting relieved the episode.