Suspension Trauma

Suspension trauma, or orthostatic intolerance, is the development of symptoms such as light-headedness, palpitations, tremulousness, poor concentration, fatigue, nausea, dizziness, headache, sweating, weakness, and occasionally fainting during upright standing. This phenomenon was recognized decades ago by fall protection researchers; however, little data was collected. It was first studied by NASA for astronauts and commonly occurs in the military or other similar situations where a person is in an upright, stationary position for long periods of time. It became a hot topic for persons wearing fall protection harnesses around 2003.

When a person wearing a full-body harness has fallen, the harness positions the body in an upright position similar to standing. This position - suspended in an upright position over five minutes with legs relaxed straight beneath the body - promotes the pooling of blood in the lower extremities, which can result in a decreased blood flow to the heart and brain. This typically occurs when the person is unconscious or incapacitated. If not corrected in time, it can result in death.

OSHA Safety and Health Information Bulletin on Suspension Trauma/Orthostatic Intolerance