Orthostatic Intolerance

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Orthostatic Intolerance Safety Talk

When working at heights, the primary hazard that is addressed is the possibility of falling. Where fall prevention, such as guardrails is not feasible, then fall protection must be used. Fall protection, such as a lanyard and full-body harness, will protect a worker from a fall, but there is an additional hazard that must be planned for. After a fall, when a worker is suspended by their fall protection equipment, there needs to be a prompt retrieval of the worker. If suspended too long, the worker will suffer from orthostatic intolerance, also known as suspension trauma.

Orthostatic Intolerance
(source: www.osha.gov)

Orthostatic intolerance may be defined as “the development of symptoms such as light-headedness, palpitations, tremulousness, poor concentration, fatigue, nausea, dizziness, headache, sweating, weakness and occasionally fainting during upright standing.”

A common example of this is when a soldier is standing in one spot too long and faints. The reason he faints is because the blood pools in his legs, and without movement, the muscles that pump the blood to and through the heart cannot work properly. This leaves the blood to accumulate in the legs and not make it back to the brain. Without the blood carrying oxygen to the brain, the soldier faints. After the soldier faints, he is horizontal, and the blood is able to flow back to the heart and onto the brain.

When someone is suspended too long in a harness after a fall, the same phenomenon can happen. The problem with this is, unlike the soldier, the person in the harness will not be horizontal after fainting. After fainting, they will remain in the same upright position, and critical organs such as the heart, brain, and kidneys are not getting blood and oxygen. Death will eventually occur if the individual is not brought down in a timely manner.

orthostatic intoleranceImportance of a Rescue Plan

In many working at heights situations, if a person falls, there may not be a straightforward way to get them down safely. This is why it is important to have a rescue plan in place before any work at heights begins. The plan should outline things such as spotters, rescue personnel, outside agencies (if needed), rescue equipment, rescue obstructions, etc. All of these things should be thought of and ready for use in case of an emergency.

If the appropriate rescue equipment or the number for an outside agency is not readily available in the case of an emergency, the time wasted could be the difference between life and death for a worker who is suspended after a fall.


Suspension trauma is an example of where a bad situation could turn worse quickly. Look at all hazards for a work task, not just the obvious ones. Have a rescue plan in place and hold rescue drills if possible. No one plans to ever fall from heights, but there needs to be a plan in place in case it does happen.

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