Orthostatic Intolerance

Orthostatic intolerance (OI) is a group of conditions that cause symptoms when you stand, but symptoms get better when you lie down. This happens when your body can’t adjust to the drop in blood pressure that occurs when you stand. When you stand, gravity pulls blood to your lower body. In OI, your systems can’t adjust to this change, resulting in low blood pressure and a fast heart rate.

When your body can’t adjust to this change, you may not have enough blood reaching your brain. This makes you feel lightheaded and can cause you to pass out.

Types of this condition

Types of orthostatic intolerance include:

• Classical orthostatic hypotension: Your blood pressure drops within three minutes of standing.
• Delayed orthostatic hypotension: Your blood pressure drops after you’ve been standing for three minutes.
• Inappropriate sinus tachycardia: You have a heart rate above 100 beats per minute at rest and have orthostatic symptoms.
• Initial orthostatic hypotension: Your blood pressure drops within 15 seconds of standing, causing lightheadedness and a fast heart rate.
• Low orthostatic tolerance: You have symptoms of an orthostatic condition, but have a normal heart rate and blood pressure.
• Neurally mediated hypotension: Your blood pressure drops quickly, and your heart rate is slow; you may faint when you stand.
• Postural orthostatic tachycardia syndrome (POTS): Your heart rate rises within 10 minutes of standing, and you have orthostatic symptoms.

Symptoms of orthostatic intolerance

Orthostatic intolerance symptoms can get worse if you’ve been sitting or standing for a while or are in a warm place. Symptoms may include:

• Anxiety
• Discomfort in your chest
• Dizziness or lightheadedness
• Syncope (fainting)
• Fatigue
• Headache
• Inability to see, focus or hear well
• Nausea
• Shortness of breath
• Sweating
• Warmth or flushing sensation

Orthostatic intolerance causes

Many illnesses can disrupt actions your body takes that you don’t have to think about. This includes sweating and keeping a stable blood pressure. And some medicines can lead to fluid loss or lower blood pressure. Causes of orthostatic intolerance include:

• Injury
• Viral illness (like a cold or the flu)
• Dehydration
• Certain medications
• Problems with your body’s autonomic nervous system
• Postsurgical recovery (bed rest)

Risk factors

People over 65 tend to get OI more than others. This is because they often take medicine for high blood pressure, and their hearts may not work as well as they used to. Other risk factors include:

• Standing up quickly
• Standing up after sitting for a long time
• Standing for too long
• Being in a warm place
• Taking medicine that lowers your blood pressure
• Having a full stomach after a meal

How to lower your risk

Ways to lower your risk of OI include:

• Move your legs before you get up after sitting or lying down
• Get up slowly (sit before standing after lying down)
• Break up a period of standing with a sitting break
• Use a personal fan to cool off
• Eat smaller meals
• Talk to your healthcare provider about adjusting medication
• If you feel faint, lie down or sit
• Tense your arm and leg muscles to try to prevent fainting if you feel symptoms start

Complications of this condition

Orthostatic intolerance can lead to:

• Falls, with possible injuries
• Fainting
• Decrease in quality of life
• Issues with activities of daily living

How doctors diagnose orthostatic intolerance

Healthcare providers diagnose this condition by collecting your medical history and doing tests, like:

• Physical exam
• Passive and active standing tests (standing against a wall or near a bed after lying down)
• Head-up tilt table test (lying on a table that brings you up to a standing position)
• Blood pressure checks when you’re sitting, then standing

How is it treated?

Orthostatic intolerance treatment helps you with symptoms, but generally isn’t a cure. OI treatments may include:

• Stopping medicines that lower your blood pressure (only with your provider’s approval)
• Getting aerobic activity (swimming, rowing or biking don’t involve standing)
• Sleeping with the bed frame raised under your head
• Drinking more fluids
• Increasing salt intake (please consult your provider before doing this)
• Wearing compression stockings
• Taking prescribed medicine

Medications

A number of medicines can help with orthostatic intolerance. Some examples include:

• Bupropion
• Erythropoietin
• Fludrocortisone
• Methylphenidate
• Midodrine

When should I see my healthcare provider?

Contact your provider when you have dizziness, syncope, shortness of breath or other symptoms of this condition. If you’re concerned about passing out, ask a friend to drive you to your appointment. It’s helpful to make a note of what you were doing when you felt symptoms. This can give your provider clues about what’s going on in your body. Bringing a log of your blood pressure readings from home to your appointment is often very helpful.

Questions to ask your provider may include:

• What kind of orthostatic intolerance do I have?
• What’s the best treatment for me?
• How soon should I have a follow-up visit with you?

What can I expect if I have orthostatic intolerance?

This condition gets better when you treat its cause. That may include changing your body position or habits. When you lie down, lightheadedness should go away. But you may feel tired afterward. If making changes isn’t enough, your healthcare provider can work with you to find the right medication.