They say 40 is the new 20 — but most Americans believe they’ve reached their physical peak at age 34, according to a study.
And most people feel old at 42.
That’s according to a poll of 2,000 Americans of four different generations — Gen Z, millennials, Gen X and baby boomers.
Joint pain has been recognized as one of the main warning signs of aging, along with a slow metabolism and prevalence in middle age.

A poll of 2,000 Americans found they believe health is at its peak at age 34 (file photo).
A New York pollster conducted a study in California by the OnePoll Foundation, a weight loss organization.
Participants were interviewed between September 1 and 12 this year and were from the United States.
An equal number were Gen Z (18 to 25 years old), Millennials (26 to 41), Gen X (42 to 57) and Baby Boomers (58-76).
Most believed that by age 42 the signs of aging had started to appear – including joint pain, gray hair and a slowed metabolism.
But 15 percent said they noticed signs of aging before their 35th birthday.
They also said that they believed that most of them expected to reach the peak of their physical and mental abilities at the age of 34.
Additionally, one in five participants said they were happiest in their 20s and 30s.
Dr. Rekha Kumar, chief medical officer at the Foundation, says that while aging is inevitable, making healthy lifestyle changes are preventative care measures that can help reduce age-related issues like weight gain and chronic disease.
‘We’ve doubled life expectancy in the last 100 years, so it’s important to be active in extending our health and longevity.’
She added: ‘Programs that not only help people manage their weight, but also include guidance on general lifestyle improvements, such as good sleep, exercise or looking after their mental health, can help people stay healthy as they age.’
American life expectancy has been increasing for decades, reaching a peak of 76 years for men and 80 years for women in 2019.
But in the wake of the Covid epidemic and the pressure on the health system in 2018, With men born in 2021 now expected to live 73 years and women 79 years.
Aging is a natural process that affects all people and living things.
Over time, damage to cells occurs due to the gradual accumulation and deterioration of their functions.
These changes are slow at first, but begin to accelerate in later years.
Muscle mass peaks in the mid-20s, but then begins to decline.
The weight of the skeleton increases until the age of 30, then it begins to fall first in the hip and spine area and finally in the fingers and toes.