When you look at the life spans that are recorded in the book of Genesis it is easy to dismiss them as something that is an exaggeration or otherwise unbelievable. In short, no one lives nearly that long today with all of our medical knowledge. So why should we believe the biblical account that tells of tremendously long life spans?
For starters, the incredible life spans pretty much end after the flood. We can’t know for sure how much the world physically changed as a result of the flood. I’m not talking about just damage that was done as a result of floodwaters but physical properties of the earth that may have been different from today. We simply can’t know how things were changed but we can speculate based on what the Bible tells us and some of what science is telling us as well.
Odds are good that the supernaturally long life spans are a result of a combination of many things. So, what are the things that could have contributed to an exceptionally long life? The first is that God is supernaturally expanding people’s life spans. God keeps people alive longer so that they populate the earth. With a normal life span and normal child bearing years, Eve may have been able to have between 20-40 kids. I give that big range because Eve would have been an adult at creation and could have immediately started bearing children. But of course perhaps she also starts aging like an adult from the beginning in which case when she would be 20 years old, perhaps she has the physical body of a 35-40 year old. Whatever the case may be, even on the high end things with 40 children, it will be several generations before there is a sizable population on earth. Can God wait out the natural process for the earth to be populated? Of course. But it is quite possible that God grants long lives in the beginning for the purpose of speeding up the population of earth.
The second possible explanation for long lives is genetics. In short, there is a longevity gene. Noah is the last to have it before it is lost with the flood. He passes it on to his children, but they only receive half of the benefits because they don’t receive it from their mother. Their half gene is then passed on to their children who only have one quarter of the benefits as Noah. This would explain why the ages rapidly decrease and at a rate that is essentially halving every generation. If you look at the generations following Noah, they are roughly half of Noah and then half again the following generation.
The third explanation is the environment before the flood. Going back to the second day of creation, we should note what takes place.
And God said, “Let there be an expanse between the waters to separate water from water.” So God made the expanse and separated the water under the expanse from the water above it. And it was so. God called the expanse “sky.” And there was evening, and there was morning—the second day.
We know that the air contains moisture and that clouds are a collection of water in tiny droplets but this appears to be more. At creation, the earth is more like a tropical rain forest that does not need rain because of the canopy of water overhead. Genesis 2:4-6 gives more indication as to what all of this looked like.
This is the account of the heavens and the earth when they were created.
When the LORD God made the earth and the heavens- and no shrub of the field had yet appeared on the earth and no plant of the field had yet sprung up, for the LORD God had not sent rain on the earth and there was no man to work the ground, but streams came up from the earth and watered the whole surface of the ground.
There was no rain and the earth essentially took care of itself because of the streams that sprung up and the moisture in the air. The thick atmosphere served as protection from the sun and numerous harmful things like radiation which we know about now. There is no telling what kinds of diseases did not exist because it could not live in such an environment. Obviously fewer diseases mean fewer things to die from.
There is one more likely difference that contributed to long lives and that is atmospheric pressure. The water in the air weighs more than simple oxygen and thus creates more pressure. Scientists have researched this and believe that the atmospheric pressure was possibly double what it currently is. Now I couldn’t begin to tell you how that is a benefit aside from the fact that it apparently is. If you’re interested, there are all kinds of research into how greater atmospheric pressure my help the body heal. Hyperbaric chambers are designed specifically to increase the pressure around the body which helps with oxygen in the bloodstream. Football players have started using these in their homes to recover from injuries. The medical community is using them for everything from treating burns, to carbon monoxide poisoning, to healing crush injuries. There are also studies being conducting regarding the use of hyperbaric chambers for the treatment of autism and even certain types of hearing loss. In other words, the world before the flood could have been an environment that allowed the body to heal itself much better than today. If the body is capable of healing itself better, longer life spans would naturally follow.
As a man of faith I don’t have a problem just believing the ages given in the Bible as truth. The Bible is full of miraculous events so I don’t have any difficulty accepting supernaturally long life spans. But I also believe that God uses natural phenomenon to accomplish incredible things as well and there are some natural things that could have been different about the ancient world that would have led to much longer lives. Whatever the case may be, the incredible life spans drop off after the flood so that by the time of Abraham people were living roughly as long as we do today. God may have still blessed people with long lives but it was a matter of 110 or 120 years which isn’t unbelievable compared to the 7,8, or 900 years before.