Lung damage associated with breath-holding diving may be a condition of high risk, which can endanger the free-diver life. They are denoted as lung squeeze, and indicate a damage of the compressed lung which may come during diving.
They become manifest as cough with expectoration of hemorrhaged sputum, thoracic pain, and the damage may be so serious that it results in unconsciousness, severe respiration insufficiency, cardiac arrest and possibly death. Prevention of this damage to occur lies in a long-term training of the rib cage flexibility and increasing elasticity of the lung tissue, minimization of abrupt movements of the body and/or thorax during diving.
At the present time procedures are sought to help uncover potentially threatening during training or sport competitions.