Lifespan. Dr David A. Sinclair

Sit on the floor, barefooted, with legs crossed. Lean forward quickly and see if you can get up in one move. A young person can. A middle-aged person typically needs to push off with one of their hands. An elderly person often needs to get onto one knee. A study of people 51 to 80 years found that 157 out of 159 people who passed away in 75 months had received less than perfect SRT scores.

      Physical changes happen to everyone. Our skin wrinkles. Our hair grays. Our joints ache. We start groaning when we get up. We begin to lose resilience, not just to diseases but to all of life’s bumps and bruises.

      Fortunately, a hip fracture for a teenager is a very rare event that nearly everyone is expected to bounce back from. At 50, such an injury could be a life-altering event but generally not a fatal one. It’s not long after that, though, that the risk factor for people who suffer a broken hip becomes terrifyingly high. Some reports show that up to half of those over the age of 65 who suffer a hip fracture will die within six months.¹² And those who survive often live the rest of their lives in pain and with limited mobility. At 88, my grandmother Vera tripped on a rumpled carpet and broke her upper femur. During surgery to repair the damage, her heart stopped on the operating table. Though she survived, her brain had been starved for oxygen. She never walked again and died a few years later.

      Wounds also heal much more slowly with age—a phenomenon first scientifically studied during World War I by the French biophysicist Pierre Lecomte du Noüy, who noted a difference in the rate of healing between younger and older wounded soldiers. We can see this in even starker relief when we look at the differences in the ways children and the elderly heal from wounds. When a child gets a cut on her foot, a noninfected wound will heal quite quickly. The only medicine most kids need when they get hurt like this is a kiss, a Band-Aid, and some assurance that everything will be okay. For an elderly person, a foot injury is not just painful but dangerous. For older diabetics, in particular, a small wound can be deadly: The five-year mortality rate for a foot ulcer in a diabetic is greater than 50 percent. That’s higher than the death rates for many kinds of cancer.¹³

      Chronic foot wounds, by the way, are not rare; we just don’t hear much about them. They almost always begin with seemingly benign rubbing on increasingly numb and fragile soles—but not always. My friend David Armstrong, at the University of Southern California, a passionate advocate for increasing our focus on preventing diabetic foot injuries, often tells the story of one of his patients, who had a nail stuck in his foot for four days. The patient noticed it only because he wondered where the tapping sound on the floor was coming from.

      Small and large diabetic foot wounds rarely heal. They can look as though someone has taken an apple corer to the balls of both feet. The body doesn’t have enough blood flow and cell regeneration capacity, and bacteria thrive in this meaty, moist environment. Right now, 40 million people, bedridden and waiting for death, are living this nightmare. There’s almost nothing that can be done for them except to cut back the dead and dying tissue, then cut some more, and then some more. From there, robbed of upright mobility, misery is your bedfellow and thankfully death is nigh. In the United States alone, each year, 82,000 elderly people have a limb amputated. That’s ten every hour. All this pain, all this cost, comes from relatively minor initial injuries: foot wounds.

      The older we get, the less it takes for an injury or illness to drive us to our deaths. We are pushed closer and closer to the precipice until it takes nothing more than a gentle wind to send us over. This is the very definition of frailty.

      If hepatitis, kidney disease, or melanoma did the sorts of things to us that aging does, we would put those diseases on a list of the deadliest illnesses in the world. Instead, scientists call what happens to us a “loss of resilience,” and we generally have accepted it as part of the human condition.

      There is nothing more dangerous to us than age. Yet we have conceded its power over us. And we have turned our fight for better health in other directions.

      WHACK-A-MOLE MEDICINE

      There are three large hospitals within a few minutes walk of my office. Brigham and Women’s Hospital, Beth Israel Deaconess Medical Center, and Boston Children’s Hospital are focused on different patient populations and medical specialties, but they’re all set up the same way.

      If we were to take a walk into the lobby of Brigham and Women’s and head over to the sign by the elevator, we’d get a lay of this nearly universal medical landscape. On the first floor is wound care. Second floor: orthopedics. Third floor: gynecology and obstetrics. Fourth floor: pulmonary care.

      At Boston Children’s, the different medical specialties are similarly separated, though they are labeled in a way more befitting the young patients at this amazing hospital. Follow the signs with the boats for psychiatry. The flowers will take you to the cystic fibrosis center. The fish will get you to immunology.

      And now over to Beth Israel. This way to the cancer center. That way to dermatology. Over here for infectious diseases.

      The research centers that surround these three hospitals are set up in much the same way. In one lab you’ll find researchers working to cure cancer. In another they’re fighting diabetes. In yet another they’re working on heart disease. Sure, there are geriatricians, but they almost always take care of the already sick, thirty years too late. They treat the aged—not the aging. No wonder so few doctors today are choosing to specialize in this area of medicine.

      There’s a reason why hospitals and research institutions are organized in this way. Most of our modern medical culture has been built to address medical problems one by one—a segregation that owes itself in no small part to our obsession with classifying the specific pathologies leading to death.

      There was nothing wrong with this setup when it was established hundreds of years ago. And by and large, it still works today. But what this approach ignores is that stopping the progression of one disease doesn’t make it any less likely that a person will die of another. Sometimes, in fact, the treatment for one disease can be an aggravating factor for another. Chemotherapy can cure some forms of cancer, for instance, but it also makes people’s bodies more susceptible to other forms of cancer. And as we learned in the case of my grandmother Vera, something as seemingly routine as orthopedic surgery can make patients more susceptible to heart failure.

      Because the stakes are so exceptionally high for the individual patients being treated in these places, a lot of people don’t recognize that a battle won on any of these individual fronts won’t make much of a difference against the Law of Human Mortality. Surviving cancer or heart disease doesn’t substantially increase the average human lifespan, it just decreases the odds of dying of cancer or heart disease.

      The way doctors treat illness today “is simple,” wrote S. Jay Olshansky, a demographer at the University of Illinois. “As soon as a disease appears, attack that disease as if nothing else is present; beat the disease down, and once you succeed, push the patient out the door until he or she faces the next challenge; then beat that one down. Repeat until failure.”¹⁴

      The United States spends hundreds of billions of dollars each year fighting cardiovascular disease.¹⁵ But if we could stop all cardiovascular disease—every single case, all at once—we wouldn’t add many years to the average lifespan; the gain would be just 1.5 years. The same is true for cancer; stopping all forms of that scourge would give us just 2.1 more years of life on average, because all other causes of death still increase exponentially. We’re still aging, after all.

      Aging in its final stages is nothing like a bushwalk, where a bit of rest, a drink of water, a nutritional bar, and some fresh socks can get you another dozen miles before sunset. It’s more like a fast sprint over an ever-higher and ever-closer set of hurdles. One of those hurdles will eventually send you for a tumble. And once you’ve fallen one time, if you do get up, the odds of falling again just keep getting higher. Take away one hurdle, and the path forward is really no less precarious. That’s why the current solutions, which are focused on curing individual diseases, are both very expensive and very ineffective when it comes to making big advances in prolonging our healthspans. What we need are medicines that knock down all the hurdles.