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Harness Hang Syndrome

by shevah
April 2006

There has been some intensive discussion on numerous rope e-groups on a condition called: HHS: Harness Hang Syndrome. This is an important issue that both rope bottoms and rope Tops need to be aware of to keep everyone safe.

What is Harness Hang Syndrome?

The cause has become known as Suspension Trauma or Harness Induced Pathology and is a particular hazard for people who work in harnesses. It is a variation of Orthostatic Intolerance, which can result in a loss of consciousness (syncope), followed by death in less than 30 minutes.

When someone faints and falls over, the reason they faint is from a lack of blood flow to the brain. Thus, fainting is the brain's natural request for more oxygen-rich blood. In nature, the problem is self rectifying - - when the person falls down, blood flow can be restored easily to the brain again once the legs, heart, and brain are all on the same level. When suspended in a harness, we are prevented from falling over and correcting any feeling of faintness or lack of blood to the brain.

It should be noted that research has shown that Suspension Trauma can result as long as the legs are immobile and lower than the heart. So even relatively flat inclinations of the body can result in the condition developing. *Research has also indicated that the type and fit of a harness is essentially irrelevant to the development of suspension trauma.

Although this is not a new problem, its pathological causes and preventions are still in its infancy.  Harness Hang Syndrome issues were first introduced to the general rope bondage world in a post on Adult Rope Art (ARA) Yahoo egroup (began in August, 2001 by Jimi Tatu) in June 2002 from Lochai with the following link about Harness Hang Pathology:

This condition is also referred to as: Harness Induced Pathology

In March 2003, a new document was published by

The US Dept. of Labor / OSHA:

"Suspension Trauma/Orthostatic Intolerance" , it states:

"Venous pooling typically occurs in the legs due to the force of gravity and a lack of movement. Some venous pooling occurs naturally when a person is standing. In the veins, blood normally is moved back to the heart through one-way valves using the normal muscular action associated with limb movement. If the legs are immobile, then these "muscle pumps" do not operate effectively, and blood can accumulate ... thus reduces the amount of blood in circulation.

The body reacts to this reduction by speeding up the heart rate in a futile attempt to maintain sufficient blood flow to the brain." The body will then abruptly slow the heart rate and blood pressure will diminish … causing fainting".

Furthermore, the article points out:


When Orthostatic Intolerance occurs, there is an increase of toxins in the pooled blood, which are usually carried away with normal circulation. Without the action of the muscle pumps, these toxins remain in the pooled blood and becomes acidotic due to the lack of oxygen in the blood.

Death can occur during or just after rescue from the victim being moved to a horizontal position, resulting in a massive return of venous blood to the shock-damaged heart. The heart and kidneys are unable to cope with this rapid re-perfusion and cardiac arrest is very possible. (This was later termed as "Rescue Death").

Suspension Trauma and Rescue Harness Safety

By, Dr. Bill Weems and Dr. Philip Bishop

December 2003, Fire Engineering

This article offers an account of a fire rescue practice exercise gone wrong - makes for an interesting read.

Will Your Safety Harness Kill You?\\ce.pdf?nl403

By, Dr. Bill Weems and Dr. Phil Bishop - March 2003, OHS

"Fall victims can slow the onset of suspension trauma by pushing down vigorously with the legs, by positioning their body in a horizontal or slight leg-high position, or by standing up. Harness design and fall injuries may prevent these actions, however."

HHS was revisited on the ARA list in September 2004:

There is a fairly recent (2002) British paper, by Paul Seddon, reports to the UK Health And Safety Initiative, that summarizes the various studies on the physiological effects of being hung in harness that is worth a serious read:

Harness Suspension:

Review and Evaluation of Existing Information

The objective of this review was to locate and study literature dealing with the effects of being suspended in a harness and evaluate and report on them, together with attendant issues regarding various types of harnesses, including the position of their attachment points.

In addition, selected harness standards were to be examined to see if and how they addressed the topic of suspension.

The study concludes that, "Whatever type of harness, hanging motionless in suspension is not physiologically safe, and will eventually lead to very serious blood circulation problems."

This subject was addressed again on the Adult Rope Art egroup on December 7, 2005, -- "Harness Hang Syndrome, Harness induced Pathology". again referring to Paul Seddon's 2002 report on the physiological effects of being hung in harness:

In 2006, the growing rope community was facing this issue again with a hands-on incident that prompted the most recent discussions and caused me to comprise all this information into one article.

A rope Top was sceening with a rope bottom and some problems resulted after she was brought down from the suspension.

Here is Gary's account from ARA, Feb 12, 2006:

"I have had the pleasure of playing with a wonderful lady who enters an almost trance-like state in a bondage tie. Recently, I placed her in a simple face down horizontal suspension. She hung motionless -- trance-like "flight" -- gently swaying back and forth to good music -- otherwise quiet room. When I started to take her down, she suffered hot flushes and nausea.

These are typical pre-syncopal symptoms associated with the "Harness Hang Syndrome." And, it was my introduction to these problems.

Let me repeat the sequence of events. (1) Her legs were motionless in a suspension and (2) when her legs and arms were released and lowered (3) she developed hot flushes and nausea. While she was in a horizontal face down suspension, her legs did hang lower than her body. She did not faint during or after the suspension -- but she remained motionless during the suspension.

Bondage and suspension safety discussions typically center around knots, support points, and ropework not constricting nerves and not causing any breathing or circulation restrictions.

Studies about the Harness Hang Syndrome problem have been conducted by people who design rescue harnesses and people who are responsible for rescuing victims who have fallen and were hanging in their safety harnesses. These studies and the HHS problems were brought to my attention by a friend who referred me to a post on the AdultRopeArt egroup by Paul (whiteknight38cdn) on December 7, 2005,

"Harness Hang Syndrome, Harness induced Pathology."

Paul is also a firefighter, a member of a group responsible for rescuing people who may suffer from the Harness Hang Syndrome.

From my analysis of the literature, it seems to me only two requirements exist for HHS to occur. 1) A body position that allows blood to accumulate from gravity (venous pooling) in the legs or arms, & 2) Lack of Motion - so that the "muscle pumps" don't redistribute the blood back into the body cavity in a near normal fashion.

It is NOT necessary to constrict the femoral vein to cause HHS.  The cause of HHS is lack of motion; not using the "muscle pumps" in the arms/legs to help redistribute the blood that accumulates in arms/legs hanging lower than the body cavity.

Advise: Don't allow your bottom to be motionless. If their legs are suspended below their body, be sure they move their legs. Make them flex their muscles. By moving or flexing their legs, they activate the "muscle pumps" in their legs and you won't have the HHS problem."


A very important comment was added by HouTxOwl :

"Inactivity is required for this to occur and so the 'trance-like' state is not a symptom but is instead a precursor to the event. Activity acts to "pump" the blood back through actions of valves in the veins and also works to periodically relieve the pressure on the femoral vein."

"The syndrome is discussed in some technical rope rescue type courses."


Clinical tests and research has been done on this subject since 1968, as a result of suspension harness deaths with parachuters, climbers, and cavers. Various papers were published on these results. All of these studies were situated using a "seat harness" with their subjects. And all the researchers concluded that: "A motionless subject in a chest/seat strap harness combination is subject to orthostasis with pooling of the blood in the lower extremities that can lead to the possibility of death during or just after rescue (so-called Rescue Death). Rescue Death is the result of an acute heart failure immediately after a rescue of a person in shock from a hanging position, because the blood, which has sunk to the lower half of the body, flows back too quickly to the heart."

After 1990, there has been numerous studies completed in suspension trauma where the subjects legs were elevated and the addition of movement of the lower extremities. It was concluded "Just the non-movement of the legs is enough to significantly reduce that circulation. If the legs and arms aren't moving, there is no pumping action, and blood tends to stagnate in the arms and legs. This means there is less blood return to the heart, and then subsequently to the head, is what leads to the faintness."

In 1997, Bariod and Thery (French Federation of Speleologists), along with Sheehan (2000), an Australian senior vertical rescue instructor, conducted various experiments, which concluded: "Fainting (in these circumstances) is a complex medical matter. Whatever the type of harness, motionless suspension in not physiologically safe and will eventually lead to very serious blood circulation problems, including death. It seems useless to try to invent a preventative harness."

It was further recommended for those who work in harnesses: Have an actual flat work-seat built into the harness to help position the upper legs horizontally and support most of the body's weight instead of leg straps. Prevention of Suspension Trauma was only successful by maintaining leg activity by moving the legs and, where possible, pushing with the feet against a firm surface at regular intervals. But no matter the type of harness; belt, chest, full body, hanging motionless was medically detrimental to the health of the suspended worker.

After review of all testing research, it was interesting to find that in every instance where Suspension Trauma did occur, each test subject indicated a degree of pain caused by the body holding devices, i.e. the harnesses and belts used.

One other factor was exposed during many of the tests in the 1990's. Allowing the head to tilt backwards (head-up tilt) induced pre-syncopal symptoms at a quicker rate. Therefore, any suspension position from vertical to horizontal where the legs are lower than the heart, the head must be supported as not to tilt back.


Excerpts from Paul's December 7, 2005, post on the AdultRopeArt egroup, referencing Seddon's Report:

- The study concludes that, "Whatever type of harness, hanging motionless in suspension is not physiologically safe, and will eventually lead to very serious blood circulation problems."

- Most of the testers believe that HHS is caused by blood being trapped in the legs so that the net result is similar to hypovolemic shock. No blood is actually being lost, but the amount of blood available in the torso to keep the brain and vital organs sufficiently perfused with blood is inadequate nonetheless.

- Look for: Faintness. Nausea, Hot flushes. Sweats. Paleness. Breathlessness. Feeling of panic, "Greying" or loss of vision. Change in pulse rate (suddenly becoming rapid, then slowing.)

- A lot of the signs and symptoms listed above, including the most important -- fainting -- may resemble a subject who is "flying", or a deep sub-space experience. This obviously compounds the danger of our activities, especially when playing with people who go into, or affect, near catatonic states.

- In order to maintain sufficient blood circulation, Ask conscious patients to do leg contractions (pumps) to reactivate blood circulation. * Note to subs: This will also help you to prolong your suspension and mitigate problems if you can flex and pump your legs occasionally while tied.


Additionally: Advise when Rescuing people from harnesses;

- All restrictive belts and clothing should be unfastened.

- - *Important! The victim must never be laid down flat after being rescued from the suspended position!

- Laying the victim down horizontally could be life threatening. The blood that has accumulated in the legs flows abruptly into the heart creating a risk of heart failure.

- He/she should be positioned with the upper body very well raised, i.e., in a seated, possibly squatting or crouched posture (raised knees) for 20 to 40 minutes. Transfer to a horizontal posture (supine) should take place only gradually!


The moral of all this information?

Knowledge = Power

Know and prevent what can happen so that you have the power in what you want to happen.

As you can see, this is not an issue that has been neglected. Research goes back decades and continues to be updated. Because we, in the rope world, do not use many of these seat harnesses and usually not stay in an upright, vertical, motionless position, this problem does not rear its ugly head too often. And when it does, it is normally just a minimal amount of symptoms that usually does not result in a deathly outcome. Can it happen? Sure, but I have not heard of anyone dying from HHS as a result of Rope Bondage Suspension.

Hence, you should know how to prevent this condition, how to treat it if one should succumb to its affects, and also be able to spread this all-important information to others.

So, if you are going to play with rope suspension, follow these 3 rules:

1) Don't have your legs and arms lower than your heart without constantly moving and pumping the legs and arms around.

2) If you are going to me motionless, trancelike, subspace flying -- do so with your heart lower than your legs.

3) Any suspension position from vertical to horizontal where the legs are lower than the heart, the head must be supported to not allow it to tilt back.

Play safe,


Delight in the journey, not the destination ~~~