Despite the perception many of us carry of being “old’, Science points to the contrary.
Recent research indicates the human body is constantly renewing and regenerating itself, resulting in many of our body parts being much younger than we realise …
Skin: Age 2-4 Weeks
The surface layer of the skin or epidermis is renewed every two to four weeks.
This rapid turnover occurs because skin is the body’s outer protection and is exposed to injury as well as pollution. Despite this constant renewal, we can still get wrinkles as we age, as the skin can lose collagen and elasticity. To help prevent this, click here.
BONES: Age 10 Years
“The skeleton is constantly replacing itself,” explains Dr Peter Selby, an Osteoporosis expert from Manchester Royal Infirmary. It takes about ten years for the skeleton to completely replace itself. “When we hit middle age this renewal process slows down, so our bones tend to get thinner, which can lead to osteoporosis”. A healthy diet and regular exercise can help prevent risk of Osteoporosis.
INTESTINES: Age 2-3 Days
“Our intestines are lined with cells called Villi – which have a very high turnover rate,” explains Tom Macdonald, Professor of Immunology at Barts and the London Medical School. These cells help absorb nutrients from food and due to constant exposure to highly corrosive stomach acid, can require replacing every two to three days. The rest of the intestine protects itself with a layer of mucus, although this barrier cannot withstand stomach acid for long; these cells renew themselves every three to five days.
HEART: Age 20 Years
The heart was originally thought not to be able to renew itself, however a recent study at New York Medical College found the heart contains stem cells that constantly rejuvenate – at least 3 or four times over a lifetime. Ground-breaking research has found Heart cells can even regenerate following Heart Attacks. 
Brain: Age Varies
“Orginally, Scientists thought we are born with all the brain cells we’ll ever have – around 100 billion – and that most of the brain does not regenerate as it gets older,” explains John Wadley, consultant neurosurgeon at Barts and the London Hospital. “However, there are two areas of the brain that do regenerate. The Olfactory Bulb that governs our sense of smell, and the Hippocampus, which is an area for learning.’ Proving that it’s never too late for an old dog to learn new tricks! 
So the next time you feel old, remember this article and the insight into how old you really are.
- Bergmann O, Liebl J, Bernard S, Alkass K, Yeung MSY, et al. The age of olfactory bulb neurons in humans. Neuron. 74, 634-639 (2012).