Orthostatic Hypotension : Low Blood Pressure as you Stand up

Orthostatic Hypotension is a form of low blood pressure which occurs when a person stands up from sitting or lying posture. In medical terms, if systolic blood pressure decreases by 20mmHg or diastolic blood pressure decreases by 10mmHg within 3 minutes of standing up from sitting or lying posture then it can be diagnosed as Orthostatic Hypotension (also known as Postural Hypotension). Usually it occurs due to old age, but there are various other medical reasons which make it happen. Here we will try to understand them and know if it can be treated.

Orthostatic Hypotension can make you feel dizzy or lightheaded as you stand up. If such episodes occur for less than a few minutes after standing up, then it is considered as mild symptoms, but if it occurs more often or last for longer duration than you should immediately consult a doctor. In some cases it can make you faint, so it should be taken seriously.

Baroreflex is our body's homeostatic mechanism which keeps our blood pressure at nearly same readings, in whatever posture we are. Baroreceptors (a part of autonomic nervous system) senses the stretch in blood vessels as our body posture changes and our brain increases or decreases pulse rate and blood pressure to keep it at an optimum level.

How Orthostatic Hypotension happens ?

When stand up suddenly, gravity comes into action and pools the blood in our legs and abdominal region, which decreases the blood pressure in upper body. In a healthy person baroreceptors located near heart and neck, sense this lower blood pressure and increase the pulse rate to take blood pressure to an optimum level. Usually this whole action get started within seconds and a healthy person don't even notice anything. But if this thing takes a little longer and blood pressure remains on lower side even after 2 to 3 minutes then it is considered as Orthostatic Hypotension.

There may be various reasons behind Orthostatic Hypotension, some of which can be easily treated or avoided but some reasons are related to medical conditions. Here we have tried to list all of the common reasons behind Orthostatic Hypotension .

• Dehydration : Dehydration is lack of water in our body, which decreases the total volume of blood thus causing low blood pressure. Dehydration can be caused by not drinking enough water, fever, diarrhea, vomiting, a lot of sweating or too much exercising without drinking any fluid. Orthostatic Hypotension caused due to dehydration can be treated and avoided by drinking enough water throughout the day.
• Heart Problems : Bradycardia, a medical condition of low heart rate can cause low blood pressure while standing up. Similarly heart valve problems, heart attack and heart failure can cause Orthostatic Hypotension.
• Nervous system disorders : Our body's blood pressure is controlled by baroreflex, which is regulated by our nervous system. So nervous system disorders can directly affect our body's ability to control ups and downs of blood pressure.
• Diabetes: Diabetes damages our nervous system and may damage those nerves that regulate blood pressure. Chances of orthostatic hypotension increases in long term patients of diabetes.
• Endocrine Disorders: Endrocrine glands system play an important role in proper functioning of our body by secreting a number of hormones as per need of body. Hormone disorders can cause diseases like diabetes and nervous system damage, which may also cause orthostatic hypotension.  
• Low blood pressure after eating meals (also known as postprandial hypotension) can also cause orthostatic hypotension.
• Lengthy bed rest on regular basis is also considered as a possible reason behind orthostatic hypotension.

Some reasons like dehydration and lengthy bed rests can be avoided or treated ourselves but for other possible reasons it is necessary to see a doctor and treat the actual medical condition.