Decompression sickness

Decompression sickness (DCS) also historically or colloquially known as divers' disease, the bends or caisson disease) describes a condition arising from the precipitation of dissolved gasses into bubbles inside the body on depressurisation. DCS most commonly refers to a specific type of scuba diving hazard but may be experienced in other depressurisation events such as caisson working, flying in unpressurised aircraft and extra-vehicular activity from spacecraft.

Source: Wikipedia - Decompression sickness