Some would argue that a person's biological age is more indicative of how old they are than their chronological age. If there was a test to tell if someone had the body of a twenty-year-old, how many would take it? Despite a limited understanding of biological age, companies are now testing anyone willing to pay up to $750 to learn their "biological" age.

The problem with this test is people may take the results literally when they shouldn't. That's exacerbated by some news media reporting the test can go as far as to tell a client how long they'll live. These companies are basing their results on something found in all human cells called telomeres, which are structures at the ends of chromosomes.

Chromosomes are made of twisted double stranded molecules of DNA. Telomeres play an important role in protecting DNA because they act as caps on the ends of chromosomes, keeping them from fraying or intertwining, thus preventing DNA mutation.

One of the consequences of aging is every time a cell in the body divides, the telomeres get shorter. When the telomeres get too short, cells can no longer divide, and they die. So, the length of the telomere is a good measurement of a cell's age and is what some companies are now using to determine a person's biological age.

The telomere measuring tests use a technology called quantitative real time polymerase chain reaction. From one drop of blood, white blood cells are isolated, broken open, and then the DNA is purified so the telomere length can be measured. This signal is compared to an unaltered gene and then a telomere score is generated. It's unclear how accurate these tests are on different people.

It's a fact that people born with shorter than average telomeres have a shorter lifespan, but it's unknown if longer telomeres equal longer lives. Until statistics are available on what telemere lengths actually predict, these tests can't tell much.

So, there's not enough data to support the claims of the companies producing these tests. Some argue the tests provide an opportunity for people with short chromosomes to alter their behavior if necessary, yet there's concern insurance companies could misuse this information to set life insurance premiums.

Just because a test is available does not necessarily mean it should be used or that there is sufficient data to understand what the results mean. What is already known is lifestyle can help determine lifespan and health. So until telomeres can reveal more, exercising and making healthy food choices are the proven and dependable options.