As people get older, their cells simply don't work as well, and can't stave off disease as easily or heal as well as they once could. As a result, older people may die from injuries or diseases that a younger person would easily survive.
We die naturally because our cells die. After they've done their job, billions of cells in your body die each day and make way for new cells. Old cells age us. Inside a cell, telomeres at the end of each chromosome contain genetic information that gets clipped away with each cell division.
You stop growing and start dying at different ages for different parts of your body. Your brain starts to shrink and lose cells at around age 50. Your skin starts to thin and become less elastic at around age 40. Bones start to shrink and weaken at around age 30.
Technically, there is no such thing as dying from old age, but it is a term that is often used to generalize someone's death, which may be down to a number of causes and factors. In the UK, dying of “old age” is used in conjunction with the term “frailty”.
While the population can expect to live longer lives on average, the human lifespan might have a cap. Scientists believe that the human lifespan could be anywhere from 120-150 years long, but not longer than that, due to accumulating hallmarks of aging and chronic disease.
With old age there is loss of some of the stem cells. This is particularly devastating in the bone marrow that has had a high turnover of cells all during their lives. But without enough blood cells there can be bleeding from a lack of platelets, serious infections from a lack of granulocytes and lymphocytes.
Demographic evidence
The longest living person whose dates of birth and death were verified according to the modern norms of Guinness World Records and the Gerontology Research Group was Jeanne Calment (1875–1997), a French woman who is verified to have lived to 122.
In the early years of life, the brain forms more than a million new neural connections every second. By the age of 6, the size of the brain increases to about 90% of its volume in adulthood. Then, in our 30s and 40s, the brain starts to shrink, with the shrinkage rate increasing even more by age 60.
The mortality rate is very low during childhood, then increases exponentially from age 30; it is lower for females at all ages.
Normally, as time passes, our cells undergo changes: Our DNA mutates, cells stop dividing, and harmful junk—by-products of cellular activity—builds up. All these processes together cause us to age.
One of the most common and well-known near-death experiences for those who die and come back is seeing a bright, white light. This white light isn't something to be afraid of. In fact, most report it coming with a sense of peace or even happiness. Many have speculated about the symbolism behind the bright light.
Death just became even more scary: scientists say people are aware they're dead because their consciousness continues to work after the body has stopped showing signs of life. That means that, theoretically, someone may even hear their own death being announced by medics.
During death, your body's vital functions stop entirely. Your heart no longer beats, your breath stops and your brain stops functioning. Studies suggest that brain activity may continue several minutes after a person has been declared dead. Still, brain activity isn't the same as consciousness or awareness.
The current age distribution of deaths is dominated by the middle-age population, ages 25-64, driven by the opioid epidemic.
Baby. Babies have no concept of death. Babies do react to separation from a parent, painful procedures, and any change in their routine. A baby who is terminally ill will need as much physical and emotional care as any age group.
In short, cognitive aging means that as we get older, our mental functions become less nimble and flexible, and many aspects of our memory get a little worse. We also become more easily distracted by busy environments, and it takes more effort to work through complex problems and decisions.
They conclude that humans reach their cognitive peak around the age of 35 and begin to decline after the age of 45. And our cognitive abilities today exceed those of our ancestors. “Performance reveals a hump-shaped pattern over the life cycle,” report the authors in Proceedings of the National Academy of Sciences.
The human brain attains peak processing power and memory around age 18. After studying how intelligence changes over time, scientists found that participants in their late teens had the highest performance.
By 2050, we could all be living to 120, but how? As hard as it is to believe, just 150 years ago the average lifespan was 40 years. Yes, what we'd consider mid-life today was a full innings for our great-great-grandparents.
Humans have a maximum known lifespan of about 120 years, but this was excluded from their calibration data for being too much of an outlier. According to the paper, which was published in Nature Scientific Reports, “this does not reflect the variability [of] the true global average lifespan (60.9–86.3 years).”
Humans' life expectancy (average) is 70-85 years. However, the oldest verified person (Jeanne Clement, 1875-1997) lived up to 122 years. As a person ages, the telomeres (chromosome ends) tend to become shorter in every consecutive cycle of replication. Also, bones start getting weaker by reducing in size and density.
Black and Mexican American children and young adults face higher death rates than their white peers. Living in a low-income household or with parents who have low education levels increases the risk of death before age 25. Suicides and homicides account for 40% of deaths among young people ages 15 to 19.
Often, people's skin colour changes in the days before death as the blood circulation declines. They can become paler or greyer or their skin can become mottled. With the loss of oxygen to their brain, they might become vague and sleepy. Some people have hallucinations and talk to 'people' who aren't there.
One of the wildest innovations is “living funerals.” You can attend a dry run of your own funeral, complete with casket, mourners, funeral procession, etc. You can witness the lavish proceedings without having an “out-of-body” experience, just an “out-of-disposable-income” experience.