Some Britons have joints that appear to be more than a decade older than their actual age, according to research on 13,000 people.
Younger people are also affected with around one in five of those aged 25 to 34 having a joint age over 50.
Some under-35s have even older joints than their parents and in some cases their grandparents, according to the statistics.
The findings are based on data from 13,000 people who submitted information about themselves to the online Joint Age Calculator, run by Seven Seas supplements.
They answered a series of questions about their lifestyles, including their occupation, weight, how much exercise they do, of what type and how often.
They noted any strenuous activities and included information on their diet, such as how much dairy and oily fish they eat, as well as noting any pains in their joints.
People were also asked to complete a series of exercises, including touching their toes and crossing one leg to see how far their knee could bend towards the floor.
The calculator is not based on a random sample of the population.
Those surveyed included 574 people aged 18 to 24, 1,110 aged 25 to 34, 2,091 aged 35 to 44, 3,560 aged 45 to 54 and about 5,000 people aged over 55.
The findings suggested that being overweight was a significant factor in joint age, with those who were overweight or obese adding five years to their joint age on average.
Osteopath Torben Hersborg, who helped to create the calculator, said: “The message is clear: joint problems aren’t something you can put off worrying about until you ‘grow old’.
“We must learn to look after our joints in the same way we know to look after our heart, weight or fitness. It requires work, but you reap the rewards.”