What happens to your body after you die?

It is difficult to generalize how people will respond to the subject of death because each of us is unique. Still, we generally feel uncomfortable at the thought of our own mortality. However, what often underlies this uneasiness is thinking about the process of dying and the fear of a prolonged or painful death rather than the state of being dead.

Ironically, despite spending a lifetime walking around in the same body and doing our best to care for it, few seem to wonder what happens to their physical remains right after death occurs. Here is a timeline of the processes involved, assuming the deceased remains undisturbed, including the transition from primary flaccidity to secondary flaccidity.

At the Moment of Death

We often think of the moment of death as that time at which the heartbeat and breathing stop. We are learning. However, that death isn't instant. Our brains are now thought to continue to "work" for 10 minutes or so after we die, meaning that our brains may, in some way, be aware of our death. The research, however, is only very preliminary.

In the hospital setting, there are a few requirements doctors use to define death. These include the absence of a pulse, the absence of breathing, the absence of reflexes, and the absence of pupillary constriction in response to bright light. In an emergency setting, paramedics look for the five signs of irreversible death to determine when resuscitation is impossible.

After death is confirmed, the timeline of physical processes is as follows.

At Hour 1

At the moment of death, all of the muscles in the body relax, a state called primary flaccidity. Eyelids lose their tension, the pupils dilate, the jaw might fall open, and the body's joints and limbs are flexible.

With the loss of tension in the muscles, the skin will sag, which can cause prominent joints and bones in the body, such as the jaw or hips, to become pronounced. As muscles relax, sphincter tone diminishes, and urine and faeces will pass.

Within minutes of the heart-stopping, a process called pallor Mortis causes the body to grow pale as the blood drains from the smaller veins in the skin. This process may be more visible in those with light skin rather than darker skin. 

At the same time, the body begins to cool from its normal temperature of 37 C (98.6 F) until reaching the ambient temperature around it. Known as algor mortis or the "death chill," the decrease in body temperature follows a somewhat linear progression: 1.5 degrees per hour.

At Hours 2 to 6

Because the heart no longer pumps blood, gravity begins to pull it to the areas of the body closest to the ground (pooling), a process called livor mortis.

If the body remains undisturbed long enough (several hours), the body parts nearest the ground can develop a reddish-purple discolouration (resembling a bruise) from the accumulating blood. Embalmers sometimes refer to this as the "postmortem stain."

Beginning approximately in the third hour after death, chemical changes within the body's cells cause all muscles to begin stiffening, known as rigor mortis. With rigor mortis, the first muscles affected will be the eyelids, jaw, and neck.

Over the next several hours, rigor mortis will spread into the face and down through the chest, abdomen, arms, and legs until it finally reaches the fingers and toes.

At Hours 7 to 12

Maximum muscle stiffness throughout the body occurs after roughly 12 hours due to rigor mortis. However, this will be affected by the decedent's age, physical condition, gender, air temperature, and other factors.

At this point, the limbs of the deceased are difficult to move or manipulate. The knees and elbows will be slightly flexed, and fingers or toes can appear unusually crooked.

At Hour 12 and Beyond

After reaching maximum rigor mortis, the muscles will begin to loosen due to continued chemical changes within the cells and internal tissue decay. The process, known as secondary flaccidity, occurs over a period of one to three days and is influenced by external conditions such as temperature.

During secondary flaccidity, the skin will begin to shrink, creating the illusion that hair and nails are growing. Rigor mortis will then dissipate in the opposite direction—from the fingers and toes to the face—over a period of up to 48 hours.