One can't maintain dismissive skepticism forever in the face of scientific and medical development communities that are ever more engaged in the development of therapies to address the mechanisms of aging. To pick one example, senolytic treatments that clear senescent cells from aged tissues are producing consistently amazing data in mice: rejuvenation, extension of healthy life, reversal of measures of many specific age-related diseases. We'll soon know how well the more viable senolytics perform in human trials, as the preliminary data from the use of dasatinib and quercetin shows that it does selectively destroy senescent cells in humans as it does in mice. Given the serious prospect of living longer in good health, I would expect the previously doom and gloom crowd of naysayers to capitulate and admit that, yes, actually it would be pleasant to have more health, more life, and less pain, suffering, and death.
People are living longer, staying healthier longer and accomplishing things late in life that once seemed possible only at younger ages. And it's not just superstars. The fraction of over-85s in the U.S. classified as disabled dropped by a third between 1982 and 2005, while the share who were institutionalized fell nearly in half. As a whole, Americans seem to be aging more slowly than before. Researchers compared how men 60 to 79 years old aged in 1988 to 1994 and in 2007 to 2010. They found that in those later years, the men they studied had a biological age four years less than the men in the earlier years, in part because of improvements in lifestyle and medications. This suggests that not only are people living longer, they're also staying healthier longer.
On one level, greater health and longevity is an old story. In 1900, life expectancy in the U.S. was about 47 years and now it's about 78. But we may also be on the cusp of something new. Over the course of the 20th century, we primarily aided longevity by tackling disease. In the first half of the century vaccines and other innovations prevented people from dying young of communicable diseases. In the second half, improvements in lifestyle and other medical breakthroughs prevented many people from dying in middle age of things like heart attacks and cancer.
But while these improvements have made it more likely that people will live to be 65, after that, aging itself takes an inexorable toll. Even if you beat lung cancer or survive a heart attack, your body's deterioration will finish you off before too long. The average 80-year-old suffers from around five diseases. That's why even if we could totally cure cancer, it would add less than three years to average life expectancy. A total cure for heart disease would give us at best two extra years. To keep the longevity train rolling it may not be enough to cure diseases. We may also need to address the underlying condition of aging itself, which is, after all, the primary risk factor for late-life decline.
S. Jay Olshansky has said "While there are no documented interventions that have been proven safe and effective in slowing aging in humans today, we are on the verge of a breakthrough." For example, as we age, we build up more and more "senescent" cells, which secrete inflammatory molecules that can effectively accelerate aging. In 2011, researchers removed these cells from mice and extended their life spans. Clinical trials on people began in 2018. It's likely that all Americans could be living longer, healthier lives. I imagine an 80-year-old bounding from bed, biking in the morning and playing softball in the afternoon. We're all on borrowed time. More time is more life, and more of it will be sweet.