Why does the blood pressure reading vary while sitting and standing?

Q: My 30-year-old relative has hypertension. When he lies down the blood pressure reading is 120/80 but while sitting or standing it varies from 130/100 to 140/110. All the tests were done 6 years ago from VMA to renogram to renal angiogarm but they were normal. What could be the cause and what other tests are recommended?

A:It is rather unusual to have blood pressure rising on standing. The rise however is marginal and several tests done have been normal. Make sure the blood pressure recorded in standing position is recorded after a few minutes of quiet standing. It could be because of the activity performed for standing, if this precaution is not taken.