Waterboarding is a form of water torture in which water is poured over a cloth covering the face and breathing passages of an immobilized captive, causing the person to experience drowning. Normally, water is poured intermittently to prevent death. However, if the water is poured uninterruptedly it will lead to death by asphyxia, also called dry drowning. Waterboarding can cause extreme pain, damage to lungs, brain damage from oxygen deprivation, other physical injuries including broken bones due to struggling against restraints, and lasting psychological damage. Adverse physical effects can last for months, and psychological effects for years.