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How long after death does rigor mortis usually begin?

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What happens to your body after you die? — death Learn what happens to the body after death.

Rigor mortis typically begins to set in approximately two to six hours after death.1

During this initial phase, the process is first noticeable in the smaller muscles of the body, such as those in the face and hands, which often show signs of stiffness within three to four hours. The condition occurs because the body ceases to produce adenosine triphosphate (ATP) once breathing and oxygen intake stop. Without ATP, the myosin filaments in muscle tissue cannot detach from actin filaments, leaving the muscles locked in a contracted, stiffened state.12

The progression of rigor mortis varies based on several factors, including the individual's muscle mass, fitness level, ambient temperature, and the body's ATP levels at the time of death. While it begins in smaller muscles, it eventually extends to larger muscle groups, typically reaching peak rigidity throughout the entire body around 12 hours postmortem.12