A small study, appearing in Hypertension—Journal of the American Heart Association (Published online ahead of print 4 February 2008), had 14 healthy subjects drink either 500 ml of beetroot juice or water. Their blood pressure was measured every 15 minutes for the hour before drinking the juice and for three hours afterward. The blood pressure was then measured hourly for the next 21 hours. The group drinking the beetroot juice experienced a significant lowering of the blood pressure even 24 hours after ingesting the juice.