The exact amount of time it takes for a high pressure of 170 to come down to normal depends on the type of blood pressure control chosen and the age of the person, and may be maintained for a few hours or for a long period of time. A high blood pressure of 170 mmHg requires a specific choice of blood pressure control. The time it takes to lower blood pressure with lifestyle control, oral medications, or intravenous medications varies. The effect of lowering blood pressure with lifestyle control is naturally slower, while lowering blood pressure with intravenous medications in an emergency or when symptoms are present may be possible in a matter of hours. Depending on age and individual differences in tolerance, the choice of a gentler way of lowering blood pressure or a more rapid way of lowering blood pressure that can be tolerated, such as in the elderly, can only be done slowly in order to lower blood pressure quickly and maintain the blood supply to vital organs. It is recommended that the blood pressure of 170 be lowered to the normal range in a specific way and time according to the specific circumstances and in accordance with medical advice.