In the final minutes of life, the body goes through a rapid cascade of changes: blood pressure drops sharply, breathing becomes irregular or stops entirely, and the brain’s activity shifts in ways scientists are only beginning to understand. Some of these changes are visible to people at the bedside, while others are happening invisibly inside the body. Here’s what we know about each stage of this process.
Blood Pressure and Circulation Collapse
As the heart weakens in its final stretch, blood pressure falls dramatically. In the hours before death, systolic blood pressure (the top number) often drops below 80 mmHg, and oxygen saturation in the blood falls below 90%. For context, a healthy resting blood pressure is around 120/80, so the body is operating on a fraction of its normal circulatory power.
This drop in circulation has visible effects. The skin, especially on the knees, feet, hands, ears, and buttocks, can turn purplish, pale, gray, or blotchy. This mottling happens because blood is being redirected away from the extremities as the cardiovascular system loses its ability to maintain flow. When mottling appears, death is typically hours to days away. The body also cools, with temperature sometimes falling below 96°F.
How Breathing Changes
One of the most noticeable changes in the final minutes is in breathing. Many dying people develop a pattern called Cheyne-Stokes respiration: cycles where breathing gradually gets deeper and faster, then slows down and stops entirely for several seconds, then starts up again. This cycle repeats because the brain’s respiratory control center is losing its ability to regulate carbon dioxide levels. CO2 builds up during the pauses, which triggers a burst of breathing, which then overcorrects, and the cycle continues.
In the very last moments, breathing may shift into what’s called agonal breathing. These are slow, irregular gasps that can look distressing. The person’s face may grimace as if in pain. But agonal breathing is a brainstem reflex, not a sign of suffering. The person is almost certainly unconscious at this point, and the gasps are the lower brain’s final, automatic attempt to keep the body alive. These gasps can continue for seconds to minutes after the heart has effectively stopped pumping.
The Death Rattle
About half of dying patients develop what’s known as a “death rattle,” a gurgling or rattling sound with each breath. It’s caused by air passing through saliva or mucus that has pooled in the throat and airways. Normally, you swallow saliva reflexively and cough to clear secretions. In the final hours, both of those reflexes weaken or disappear, and lying in a reclined position lets fluid accumulate. The sound is generally more distressing for people in the room than for the dying person, who is typically unconscious or deeply unresponsive by the time it begins.
What the Brain Does in the Final Moments
Perhaps the most surprising discovery in recent years involves what happens inside the brain as it loses oxygen. A 2023 study published in JAMA found that some comatose patients showed a surge of high-frequency brain waves (gamma oscillations) in the moments after life support was removed. These gamma waves appeared in the posterior region of the brain associated with conscious experience, mirroring patterns seen in people who are awake or dreaming. None of these signals were present before ventilation was removed, meaning they were triggered specifically by the dying process.
This finding may help explain near-death experiences. The AWARE II study, which examined cardiac arrest survivors at multiple hospitals, found that about 39% of survivors who completed interviews reported some form of memories or perceptions from the time they were clinically dead. These experiences fell into distinct categories: some people recalled dream-like experiences, others described transcendent experiences researchers call “recalled experiences of death,” and a small number reported awareness during CPR itself. The study concluded that consciousness, awareness, and cognitive processes may occur during cardiac arrest, even when the brain appears to have shut down by external measures.
Hearing May Persist to the End
There is a long-standing belief that hearing is the last sense to go, and recent evidence supports it. A study published in Scientific Reports used EEG monitoring on hospice patients in their final hours. Even when patients were completely unresponsive to voices and touch, 80% still showed brain responses to changes in sound. Their auditory systems were responding to tone changes in ways similar to young, healthy control participants, just hours from the end of life.
The responses were not identical to those of conscious people. Unresponsive patients could detect simple changes in tone but showed weaker or absent responses to more complex pattern changes, suggesting a reduced but real level of auditory processing. The practical implication is straightforward: people who are present with a dying loved one may well be heard, even when there’s no outward sign of awareness.
Terminal Lucidity
Some dying people experience a brief, unexpected return of mental clarity in the hours or days before death. This phenomenon, called terminal lucidity, is especially striking in patients who have been confused or unresponsive for weeks. In more than 80% of documented cases, observers reported a complete return of memory, orientation, and the ability to hold a coherent conversation. Some patients who hadn’t recognized family members in months suddenly called them by name.
How often this happens depends on how you measure it. In one study, about 70% of nursing home caregivers said they had witnessed it in dementia patients over a five-year period. A prospective study that tracked 100 consecutive deaths in a hospice found six cases, or 6%. The episodes tend to be short-lived: more than two-thirds of patients who experienced terminal lucidity died within two days of the lucid episode. Scientists don’t yet have a clear explanation for why it happens, particularly in patients whose brains have been severely damaged by dementia.
Clinical Death vs. Biological Death
When the heart stops and breathing ceases, that’s clinical death. Within seconds, brain activity comes to a measurable halt. But this is not the same as irreversible biological death. Brain cells don’t die all at once. Contrary to the older belief that brain damage becomes permanent after 5 to 10 minutes without oxygen, evidence now suggests that brain cells die slowly over many hours, even days, after the heart stops.
This is why CPR and emergency intervention can sometimes bring people back. The window matters enormously, though. Someone whose brain has been without blood flow for less than 5 minutes has a much higher likelihood of recovery than someone who goes 30 minutes without circulation. With each passing minute, the injury to cells accumulates, making meaningful recovery progressively less likely even if the heart can be restarted.