Do you know what happens to our bodies after death? No, I’m not talking about spirituality. I’m talking about physically what happens to our bodies after we die. As it turns out, it’s pretty complicated, not yet fully understood, and utterly fascinating.
What Happens To Our Bodies After Death
Medically, human beings are pronounced dead when our hearts stop beating. Of course, this is easy to determine if someone dies in a medical setting, such as in a hospital, hospice, or long-term care setting. When someone dies in a different location, for example, in an accident or if their body is found hours, days, weeks, or even years after they’ve died, however, how do you know when they died? This is when knowing what happens to the body after death comes into play. Not only is it beneficial for the loved ones of the deceased, but it can help solve criminal cases, as well.
What Defines “Death”?
I know I just said that doctors typically pronounce someone as dead when their heart stops beating and a pulse is absent. However, when your whole body dies is slightly more complicated and not quite so instant. After your heart stops beating, it takes a bit of time for other organs to stop working as well. For example, scientists have realized that our brains continue to “work” for up to 10 minutes after our heart stops. This could mean that we may be aware of our death before our brain turns off forever. (1)
Cardiac arrest, when the heart stops pumping blood to the body, is considered clinical death. Brain death is when something happens, and the brain stops sending signals to the body; this is called biological death. This is because someone in cardiac arrest does have the potential to be resuscitated. Brain death, however, is seen as a point of no return.
When paramedics arrive on the scene of a call, they look for something called “the five signs of irreversible death.” These include (2):
- Postmortem lividity – When the blood is no longer flowing and has settled into the lowest points of the body. These areas will turn blue and look somewhat like bruises.
- Postmortem rigidity (Aka rigor mortis) is when the muscles and joints “lock up” or turn stiff after death.
- Burned beyond recognition
There are, however, stages to human death. Scientists have studied this and note that it follows a specific pattern or “flow of events.”
Step 1: The Moment Of Death
When you first die, your whole body relaxes. Pupils dilate, eyelids lose tension, the jaw falls open, and all your muscles relax. Things inside your body, like your sphincters, relax, too, as the brain is no longer telling them not to. This means that any leftover waste – urine or fecal matter – will be released.
Step 2: Pallor Mortis
Within minutes of the heart stopping, the body begins turning pale. This is because the blood drains from smaller veins and vessels in the skin and pools in larger ones at the lowest points of the body.
As mentioned earlier, parts of the body will appear blue or bruised, while others are quite pale. This is because of blood pooling, known as livor mortis, and it takes a couple of hours to happen as the process is governed by gravity. (3)
While this is happening, the body begins to slowly cool down at a rate of about 1.5 degrees per hour. This process will continue until the body has dropped from the standard 37 degrees celsius to the temperature of its environment.
Step 3: Autolysis
This is also known as self-digestion. In life, our bodies are covered inside and out by bacteria and microbes. Within minutes after our hearts stop beating, our cells no longer have the oxygen they need. They become highly acidic, and toxic byproducts of chemical reactions occurring in the body accumulate. Our immune systems are no longer functioning, so enzymes, bacteria, and microbes begin their work breaking down the body (aka decomposing).
Usually, this process begins in the liver because it is rich in enzymes and has high water content. Without our immune system working, the bacteria and microorganisms previously kept out of most of our internal organs are now allowed to spread quickly to every part of the body.
Whereas the enzyme takeover begins in the liver, the bacteria takeover starts in the gut. Why? Because the gut, which consists of our stomach, small and large intestines, has the highest concentration of bacteria. They spread from the gut to the entire digestive system, then the lymph nodes, liver, spleen, heart, brain, and finally the reproductive organs.
Step 4: Rigor Mortis
Approximately three hours after death, the body undergoes chemical changes as it’s depleted of its energy sources. The proteins that previously controlled muscle contraction and relaxation stop working, and the muscles become stiff, locking up the joints in the process. It usually begins in the face with the eyelids, jaw, and neck muscles. From there, it continues down the body until the entire body is stiff as a board.
This process will be fully complete between 7 to 12 hours after death. The variance in time depends on age, gender, air temperature, the physical condition of the deceased, and more. In children and infants, rigor mortis might not happen at all due to their small amount of muscle mass.
Step 5: Secondary Flaccidity
There are chemical changes that are continuously happening in the hours after we die. For this reason, after 12 hours, the muscles will start to relax again. Internal tissue decay also contributes to this. It takes about 48 hours for rigor mortis to cease altogether.
Step 6: Natural Decay
The process mentioned in step 3 is slow and continues throughout steps four through five and beyond. It takes a while for a body to fully decay until all that is left are the bones. This time depends on the environment in which the body is kept. For example, being buried in a bog or ice will preserve the body quite well. In other situations, less so.
The More You Know
Obviously, it can be rather uncomfortable talking about death, even in a very scientific, pragmatic format such as this. That being said, knowing what physically happens to the human body after we die is essential for many aspects of science. After learning about this process, however, one thing is certain: I am thrilled that my job does not involve handling or studying dead bodies.