What exactly is the Hayflick Limit? I'll tell you.
Basically the Hayflick Limit states that the maximum number of times that cells may divide is finite and somewhere between 40 and 60.
Prior to Leonard Hayflick's experiments in 1961 cells were thought to possess the ability to divide an infinite number of times.
So, what does this mean to you? It means you're not going to live forever. The Hayflick Limit essentially limits how long the human body can repair itself before it gives out. Hope that your limit is closer to 60 than 40.
Oh, by the way, it also pretty much rules out any chance of people living to ages near 900 like in the Bible. The simple fact is that ancient peoples exaggerated everything about their cultural heroes including how long they lived.
In a Persian epic poem several Shahs are said to have had extremely long lifespans. Zahhak lived 1000 years, Jamshid 700 years and Fereydun 500 years.
In China Zeng Pu supposedly lived for 800 years during the Yin Dynasty and Zuo Chi lived for 300 years during the Three Kingdoms Period.
Similar legends can be found in Japan, Korea, the Roman Empire, Poland and the Czech Republic.
All of these lifespans are as impossible as those in the Bible.