Doctor who reversed biological age by 75% in test subjects reveals easy way to spot how fast your body is ageing

For all of time people have been obsessed with how the body ages, as efforts to live for as long as possible have led to countless new discoveries and ways of living across history.

While most might not be quite as extreme as biohackers looking to live forever by 'cheating' death, most people you know will engage in at least a handful of habits in an effort to extend their lifespan.

One aspect that has challenged experts and scientists for years, however, is accurately estimating how old people are from a biological standpoint respective to the time they've spent on Earth — yet one doctor claims that he has found the secret.

Australian-American biologist Dr David Sinclair, a tenured professor at Harvard's Department of Genetics, has previously made a name for himself when it comes to studies on biological age, boasting some rather impressive claims.

Biological age expert Dr. David Sinclair has suggested a major tell in the overall condition of your health (Craig F. Walker/The Boston Globe via Getty Images)

He previously managed to succeed in 'reversing' the biological age of a number of test subjects, suggesting that we'll soon be able to treat the malaises of old age as if they were any other condition, and he's now offered up a new way for people to estimate their overall health themselves.

As shared by CNBC TV18, Dr Sinclair has proposed that your fingernails could hold the secret to your biological age, as new research reveals how growth slows down as you reach the latter stages of life.

After the age of 25 your nail growth slows down gradually by around 0.5 percent per-year,, with an average reduction of roughly 50 percent across a lifetime, with Dr Sinclair suggesting that the cause of this relates to the deceleration of regenerative cellular activity.

Your fingernails could prove to be a key sign of your biological age, as they slow down across the years (Getty Stock)

Effectively, your nails reflect the overall condition of your body, and slower nail growth relative to your chronological age could suggest that your biological age is gaining faster than expected — with the opposite offering a more positive scenario.

It has been noted that this shouldn't necessarily be relied on as a definitive indicator of biological age or the overall condition of your health, but instead a suggestion or hint towards certain aspects of cell regeneration that could be the catalyst for further investigation.

Blood circulation, nutrient delivery, and cell division all play a part in how fast your nails grow, so reduced function in this area could prove to be more telling than you might expect and prompt you to seek out further advice.