Two studies were released this week that illustrate the fragility of our average American life span...and give hope for ways we can extend it.
It's Halloween, so let’s start with the morose news first: The once steady decline in the American death rate has stagnated. American Cancer Society researchers recently analyzed 43 years of mortality data (1969-2013) and found that while the trend has been unequivocally downward, the most recent years (2009-2013) have shown no decline (or a statistically insignificant 0.4%, to be precise). In other words, we are currently at a standstill with our population’s overall ability to stave off death. The research was published in the Journal of American Medicine.
Sabrina Tavernese of the New York Times gives a synopsis of the research and comments that the study itself could not account for the reasons behind the stagnation, but plenty of experts have opinions.
Some suggest that the obesity epidemic is blame. Others think that the life-extending effects of statin drugs have topped out.
But analyzing the dead will only get you so far, Tavernese explains, quoting Dr. S. Jay Olshansky of the University of Illinois at Chicago:
You need to look at the health status of the living,” not the mortality statistics of the dead, he said, adding that obesity is afflicting younger generations in a way that will eventually make the numbers worse.”
Gretchen Reynolds of the New York Times offers some good news for our life expectancy. To understand this news though, we’ll need to dip back into our high school biology and remember telomeres.
Telomeres are the protective ends of DNA that keep it from degenerating–essentially the part of our DNA that keeps our cells healthy and alive. In general, the shorter the telomere, the shorter the life of that cell. Research has shown that healthy eating can extend the fortitude of our telomeres, but there have been very few studies that look at the relationship between telomere length and exercise.
Scientists out of the University of Mississippi and UC San Francisco gathered data from the CDC NHANES cohort (an annual survey) and analyzed the relationship between self-reported exercise and telomere length. The results were clear that exercise greatly decreased the risk of having short telomeres. In fact, respondents who reported doing four different varieties of exercise were 59 percent less likely to have short telomeres. These trends were particularly strong for respondents who were middle aged (40-65). (The study was published in the journal Medicine & Science in Sports & Exercise.)
Reynolds is quick to caution that though there was a statistically significant correlation between exercise and telomere length, the study does not show that exercise is the mitigating factor in prolonging cell life. The study also lacked clear data on prescriptive amounts of exercise (duration, frequency, intensity, etc..). Other study limitations include a scientific lack of clarity on the relationship between telomere length and overall well-being. Quoting the lead researcher:
Perhaps most important, the results don’t tell us whether longer telomeres translate into better health. But, Dr. Loprinzi says, other studies, including from his lab, 'have shown that telomeres are predictive of mortality,' with shorter telomeres equating to shorter lives.'
So the message seems clear, he says. “Exercise is good” for your cells, and “more exercise in greater variety” is likely to be even better.'
It’s not new that exercise is good for our bodies, and that it can help slow down the aging process.The exciting thing about this study is that it offers more information about how exercise may be helping us on a genetic level. The power to extend our lives may be in our own hands. That’s all the more reason why we must continue to understand the ways that lifestyle choices are affecting our overall health, and continue to work so that those choices are available to all Americans.
It’s also easy to hope that science, modern medicine and good old fashioned determination are going to push our life expectancies indefinitely upward. Perhaps there is some astral plane on which infinite existence is possible, but here on Earth, to the best of our knowledge, death is an implicit part of life. But, before we delve too deeply into the Dia de los Muertos spirit, we also must acknowledge that a lot of us have the ability to extend the quality of our life and the even the length of our life by making healthy choices. That’s one of the contradictions of living is it not? Our mortality will eventually catch up with us, but until it does we strive for a full existence.
Temporal Trends in Mortality in the United States, 1969-2013 via Journal of American Medicine
Does Exercise Slow the Aging Process? via NY Times
Movement-Based Behaviors and Leukocyte Telomere Length among US Adults via NCBI (National Center for Biotechnology Information)