High blood pressure limits response to low oxygen

High blood pressure limits protection of vital organs and tissues in low-oxygen conditions, a study shows.

Researchers from the Fluminense Federal University in Brazil and the University of Copenhagen in Denmark measured the blood flow to the brain and leg muscles of 19 middle-aged men, half with high blood pressure, while they inhaled air with a low oxygen concentration for five minutes.

When a healthy person has hypoxia – caused by reduced oxygen in the air – their body compensates by increasing blood flow to vital organs and tissues such as the brain and muscles in order to maintain oxygen supply.

Understanding why

But this blood flow response to hypoxia did not occur for middle-aged men with high blood pressure. This means that when they are deprived of oxygen, the delivery of oxygen to parts of the brain and the