When to get old?
According to modern scientific understanding, aging begins from the moment of birth and is a natural, continuous process throughout life. There you have it :). But aging is usually associated with various diseases - physical and mental - that will inevitably catch up with you at X years of age.
Life expectancy has been trending upward since the late 19th century, and according to UN data, the world's population aged 60+ more than doubled from 1980 to 2017, reaching 962 million people. By the end of the century, this group could reach 3.1 billion people. As birth rates decline, the planet's population is inevitably aging. By 2100, a quarter of Earth's inhabitants will be 60+ years old. As of 2024, there are almost a million people aged 100+, with Japan being the leading country. An eight-fold increase is expected by 2050.
The first signs of aging, in the form of skin changes, may begin in the 20s-30s. Starting with fine lines around the eyes and forehead, followed by more pronounced wrinkles, loss of skin elasticity, and age spots.
The most common age-related diseases include cardiovascular disease, hypertension, cancer, dementia, and osteoporosis. This article states that they usually begin to manifest at age 85. In general, the article designated the 60-70 age group as "young-old".
Everyone agrees that there are many factors contributing to premature aging, such as: excessive sun exposure, smoking, poor nutrition, lack of physical exercise, and stress. Aging also depends on genetic and environmental factors.
The same applies to the brain, which begins aging in adulthood (a broad concept). Peak brain thickness occurs at age 2, and gray matter volume peaks at age 7. White matter volume peaks at around age 30, then declines in later adulthood.
It's worth remembering that our brain is very plastic and can compensate for age-related cognitive decline by recruiting other brain areas to maintain cognitive functions. The usual recommendations for a healthy lifestyle, along with staying mentally and socially active, help mitigate the effects of aging.
This article states that aging doesn't mean inevitable health deterioration, because it can be greatly influenced by maintaining a healthy lifestyle and preventive measures.
It turns out there's no clear boundary when old age and ailments will catch up with you. Much depends on yourself. Epigenetics also has enormous influence on this process, so if you inherited some "bad" genes, that's still no reason to give up.
Photos of Ernestine Shepherd, born in 1936.