Practical, proven methods for staying healthy and active later in life.

Most of us think we know what aging means. Sore backs, sluggish brains, wobbly gaits, lonely hearts. And, true, the mind and body eventually do give out. But it doesn’t have to be all bad — there’s a lot we can do to live not just longer, but better.

Picture a graph. Instead of a long line sloping slowly downward — a miserable decline with increasing illness and injury along the way — envision one that stays high, up at the top of the graph. Only at the very end does this line drop down. Illness and disability, in other words, are compressed into a shorter period before death.

This is what scientists call “squaring the curve.” Put differently, it means that our “health span” — the years in which we are healthy and active — can last almost our entire lives. And that’s something that, to a significant extent, we can control.

Up to age 80 or so, longer life is mostly due not to genetics, but to environmental factors, including healthy behaviors such as physical activity, says Daniel Lieberman, chair of the department of human evolutionary biology at Harvard University.

Before modern medicine, Lieberman adds, “Life span was determined by health span. Our hunter-gatherer ancestors had to be active until they died. In turn, staying active turns on the processes that keep the body healthy.”

Steven Austad, a bio-gerontologist at the University of Alabama at Birmingham and senior scientific director of the American Federation for Aging Research, says: “As a species, we did a lot of physical activity for 300,000 years, until very recently.”

For us modern folk, the formula for maximizing our health span can be as straightforward as getting off the couch and walking or doing some other physical activity — you don’t even have to call it exercise — almost every day. It means eating right — more veggies, fewer doughnuts. Connecting with other people to keep loneliness at bay. And avoiding hazards like scatter rugs and cluttered hallways that lead to broken hips, and, all too often, shortened lives.

We now live in a world with growing numbers of old people, including people older than 100. So, what is accounting for longer lives?

Essentially, we have had a safer environment since the 1900s, with basic public health standards when it comes to such things as water, working conditions, refrigeration, and vaccinations, says Tom Perls, professor of medicine at Boston University and director of the New England Centenarian Study, the world’s largest ongoing study of people age 100 and older. Those factors have allowed more people to live past childhood illnesses and injuries into adulthood.

But making it to 100? Or 105? At that point, Perls says, it’s not good behavior so much as pure luck — in the form of genes. The centenarians he has studied all fit 27 genetic patterns. These genes slow aging and decrease the risk of age-related illnesses such as heart disease, stroke, cancer, diabetes, and dementia.

There may actually be an evolutionary advantage to having older folks around. Think about the resources that grandparents often provide — food, baby-sitting, college tuition — that can help family genes get passed down by supporting younger generations to reach reproductive age.

Then there’s the invaluable knowledge that older people bring to our communities. I saw this firsthand in 1993 when the Globe sent me to a Navajo reservation to report on a deadly outbreak of hantavirus — a group of viruses associated with rodents — rocking the Four Corners region of the Southwest. It was the tribal elders, speaking to researchers from the Centers for Disease Control and Prevention, who provided key information.

The elders remembered that earlier in the 20th century, they had observed increased rainfall, which led to more piñon nuts, which led to more deer mice, which led to more mouse poop, which aerosolized. Then, when inhaled, this toxic dust infected tribal members’ lungs.

When I last wrote about the research I did on aging and exercise (Blog #4, March 23, 2020), I focused on one of the major ways biologists can tell where a person is in the aging process: the epigenetic clock. I described a process called DNA methylation, signals that tell certain genes to whether to become active or not.

This time, I’m going to focus on another major hallmark of aging: telomere shrinkage. (For more detail, check out my latest book, Exercise is Medicine, from Oxford University Press.) Telomeres are tiny bits of DNA on the ends of chromosomes, like those little plastic aglets on the ends of shoelaces. Telomeres keep the DNA from unravelling – frayed, unraveled  telomeres would mess up the delicate process of cell division.

With aging, telomeres naturally get shorter, which ultimately means they are unable to keep DNA in good enough shape for the cell to divide properly. Whether shorter telomeres are just a sign of aging or an actual cause is not clear. And, for the record, some scientists think the whole telomere story has been greatly hyped as an explanation for aging.

That said, it’s a hot area of research, including whether interventions like dietary changes and exercise can help keep telomeres strong and healthy.

In 2017, an exercise science professor at Brigham Young University named Larry Tucker stunned the community of researchers exploring the potential effect of exercise on telomeres.

Tucker’s study wasn’t the first time anybody had shown a positive association between exercise and longer telomeres in people, not just lab rats. Nor did it prove cause and effect. And it didn’t settle the question of whether exercise just maintains telomere length or might increase it.

But Tucker’s study of 5,823 adults aged 20-84 made headlines nonetheless. In his analysis of this large, random sample, Tucker showed that people who habitually exercised had much longer telomeres than sedentary folks – a difference that, if telomere length is truly a biomarker of aging, would be the equivalent to 9 years less cellular aging.

Other studies showed fascinating results, too. In a 2017 study of women whose average age was 79.2, researchers from the San Diego School of Medicine found that those who did more leisure-time physical activity had longer telomeres. In another San Diego study that tracked activity levels with accelerometers (Fitbit-like devices), older women who did at least two and a half hours a week of moderate physical activity had longer telomeres than those who did less.

In a third San Diego study, researchers found that higher sedentary time, as measured by accelerometers, may be associated with longer telomeres.

To be fair, not all studies have lined up as expected. A South African study of marathoners found no difference in telomere length between marathoners and sedentary folk. Even a 2015 meta-analysis of more than 30 studies involving 41,230 people came up empty.

In other words, the idea that exercise can keep telomeres long is very much an open question. Nonetheless, I decided to go online and take a commercial telomere test. The independent scientists I had talked to warned me that the methodology used in these commercial tests is far inferior to that used in research labs. Still, I was curious.

I sent away for the test, pricked my finger and sent the blood sample off to the company. A week or so later, the results came back: I was 10 years younger than my chronological age.

Too bad I can’t believe it. The commercial tests are just too unreliable.

(Originally posted on Pyschology Today)

Katy Weinberg was 25 in 2006, a Peace Corps volunteer in Zambia teaching HIV awareness and prevention, when she stumbled upon what would become the backbone of her current project: recruiting and training artists, especially musicians, to get vital public health messages out to the public.

In Zambia at the time, HIV/AIDS was – and still is – the number 1 cause of death. Getting people with limited education accurate information on how the virus was spread was crucial to saving lives. To that end, she invited a young pop singer named Ephraim “Son of Africa” Mutalange to be the emcee at a community HIV education meeting. Thousands came to hear him and the public health message Weinberg’s group was promoting. That event would linger like an advertising jingle in the back of her mind.

Fast forward a few years, during which Weinberg earned an MBA from Boston University and a Master’s in Public Health from the Harvard T.H. Chan School of Public Health. The idea of using musicians to promulgate public health messages still echoed in her mind. She eventually got a job managing the Global Health Program at Boston Children’s Hospital, where she won a grant from the band, Aerosmith, to keep up her AIDS prevention efforts.

Still channeling her Zambian friend, Ephraim, Weinberg went back to Zambia in 2016. She worked with Ephraim on a song to teach young Zambians, especially girls, how to resist “Sugar Daddies” and others who promised money and favors in return for sex. The song, called “Worth More,” touted the lyrics “You’re worth more than material things.”

In 2019, Weinberg and Ephraim worked together again, this time convening a small group of other artists, public health experts from Children’s and the Zambian Ministry of Health, among others, and came up a new song – in two tribal languages, Nyanja and Bemba, as well as English. The song, about HIV, took social media by storm, garnering more than half a million views, Weinberg says.

Today, Weinberg and her Zambian friends are at it again, this time because of the COVID-19 pandemic. Thanks to the public health training they’ve already received, she says, a team of Zambian musicians is poised to release new songs to help stop the spread of this disease.

To be sure, artists have immense power to influence behavior for evil as well as good.

German filmmaker Leni Riefenstahl, for instance, used her talents to make highly effective Nazi propaganda movies in the 1930s for Adolph Hitler, a clear example of an artist’s power to harm.

Somewhat less malevolently, prominent American artists and celebrities have used their power recently to promote such dubious health tips as bird poop facials, drinking one’s own urine, placenta smoothies, and perineum sunning, a technique that actor Josh Brolin tried, which resulted, predictably, in a painful burn on his anus.

Even dumber? A social media “challenge” urging teens to lick substances including toilets and grocery stores items that might contain COVID-19.

But it’s the positive use of artists for public health message that most interests Weinberg, and no time more so than the present.

Recently, for instance, Surgeon General Jerome Adams, speaking on “Good  Morning America,” urged American media personality Kylie Jenner to convince her young followers that COVID-19 is dangerous to them as well as older people. She got the idea, and quickly posted a social distancing message to her 166 million Instagram followers.

Other artists are using their influence, too. American rapper Logic (born Sir Robert Bryson Hall II) took the national suicide hotline number “1-800-273-8255” as the title of a moving video to help prevent suicide. It has reportedly garnered hundreds of millions of views on YouTube.

Bon Jovi recently urged his Instagram followers to help create a new song about dealing with the COVID-19 pandemic called “Do What You Can.” Weinberg was delighted, noting that Bon Jovi uses himself as a role model and the song to reinforce the social distancing message health care professionals are trying to get across.

It’s not just Americans who are using their musical talents to push hand-washing and social distancing.

In Italy, hardy souls have been belting out arias from their porches, becoming a worldwide TV sensation. In Vietnam, musicians came up with a COVID-19 song that features animated creatures with face masks bouncing around touting the virtues of hand washing.

In Zambia, thanks to the training Weinberg’s team had already put in place,  Zambian musicians were already psyched when the pandemic struck and have created new songs to help stop the spread of the disease.

In Uganda, a group of musicians led by Bobi Wine get the message across engagingly in 3 minutes and 36 seconds minutes of upbeat, catchy singing.

I strongly recommend listening to the Ugandans. Whether or not you end up singing along with them, as I did, I guarantee you’ll get the message.

And in the process, you’ll hear the immense power of music to spread the word.

(Originally posted on Pyschology Today)

Okay, fess up. Are you sitting around just waiting for COVID-19 to go away? Chances are we all are losing fitness by the day, and that we are all sitting even more than we usually do, which is bad enough, as I discuss in my new book Exercise is Medicine.

So, here’s some motivation to get you off – and at least walking circles around — the couch.

In the latest (April) issue of the journal Medicine & Science in Sports & Exercise, British researchers reported on their observational study called “Walking Away From Type2Diabetes.”

They set out to see if people could learn to substitute some light physical activity for sedentary time. They collected data from 647 participants at high risk for diabetes, including people over age 65 and those who were obese. A third of the group were women. The participants wore accelerometers –those little devices that track physical movement – except while they slept.

Sure enough, the researchers found after one year that reallocating time from sitting to light physical activity paid off. Every 30 minutes that a person substituted movement for sitting around was correlated with smaller waistlines, lowered blood sugar, lowered triglycerides and overall reduced cardiometabolic risk. And the more intense the physical activity, the bigger the improvements.

That finding fits with the research I talk about in my book. Not to put too fine a point on it, sitting too much – all by itself – can raise the risk of disease and premature mortality, even if you dutifully exercise. In fact, many well-educated people do exercise, but they’re also more likely to have desk jobs.

One large 2012 study of 240, 819 healthy American adults, for instance, showed that more time spent sitting was linked to premature death from heart disease and cancer. In fact, even among people who exercised more than seven hours a week, watching TV for more than seven hours a day was linked to a 50 percent greater risk of all-cause mortality and a two-fold greater risk of cardiovascular mortality.

Sobering, isn’t it? Especially since the average American sits for 13 hours a day – way too much.

But take heart. Replacing just two minutes of sitting every hour with a bit of moving around helps mitigate the risks of sitting. Even better, don’t sit for more than 30 minutes at a stretch. Set your watch or a timer to ping you every so often, then get up, get a drink of water, sort the laundry, go to the bathroom, anything that makes you stand up and move.

Why, you may be wondering, is something as natural as sitting so bad. Lots of reasons, actually. But a major one is that sitting increases visceral fat. Visceral fat is not an inert blob of tissue, as once thought, but an active organ that pumps out chemicals called cytokines (adipokines) that lead to chronic, systemic inflammation. Chronic inflammation, in turn, leads to insulin resistance (a precursor of diabetes), atherosclerosis and neurological degeneration, among other things.

It gets worse. A sedentary lifestyle is also linked to high cholesterol, metabolic syndrome, gallstones, asthma, chronic obstructive pulmonary disease, some cancers, cognitive dysfunction, dementia, osteoarthritis, low back pain, frailty, decreased functional independence, constipation, muscle weakness, depression…need I go on?

Indeed, physical inactivity (a broader category than just sitting) is so lethal – and so common – that it now accounts for an estimated 5.3 million deaths worldwide, according to a landmark 2012 study. That’s 9 percent of all premature mortality (death before a person’s statistical life expectancy).

On the plus side, even just standing – not exercising, but simply not sitting – would reduce premature deaths from all causes, according to a study of 16,585 Canadian adults.

The take-home lesson is clear: Yes, we’re under house arrest at the moment, and for the foreseeable future. But we don’t have to take this pandemic sitting down.

(Originally posted on Pyschology Today)

A couple of weeks ago, before we got seriously distracted by COVID-19, I wrote in this blog about new research that scientists in Europe, the United States, and beyond have done to pin down the exact mechanisms associated with aging.

As I describe in Exercise Is Medicine, that there are nine major “hallmarks” of aging, that is, nine specific genetic and molecular events that comprise the process of aging. The good news is that exercise can affect all nine of these in a positive direction. The bad news is that eating too much and exercising too little has the opposite effect.

One of the most intriguing of these hallmarks is the epigenetic clock. This is a kind of biological metronome that “is literally an age estimate for any cell type, tissue type or organ,” says Steve Horvath, a professor of human genetics and biostatistics at the University of California, Los Angeles.

Epigenetics, in case you’ve forgotten, consists of the changes to DNA that influence which genes are active but don’t change the DNA itself. (Changes to the DNA itself are called mutations.) The epigenetic clock is actually just one of a number of biological clocks that help the body keep track of time. When should we get hungry? When should we sleep? When should we conceive babies? The most familiar of these clocks is the circadian clock, which keeps track of day and night.

But the epigenetic clock stands out because of its surprisingly strong relationship with chronological age. As Horvath puts it, it’s like counting the rings on a tree to estimate its age.

Here’s where it gets even more interesting. One of the chief epigenetic changes is a process called DNA methylation. That sounds intimidating, but it’s really not. DNA methylation is the process that happens when a chemical structure called a methyl group latches on to certain stretches of DNA. Depending on where the methyl group lands, it can control the expression of particular genes. As we age some sites on DNA gain methyl groups and others lose them.

The coolest study I came across while researching is this one: In 2014, Swedish researchers asked a group of healthy young men and women to subject themselves to muscle biopsy tests in both legs, then asked them to ride bikes in the lab using only one leg four times a week for 45 minutes for three months. Then the muscle biopsies were repeated.

The scientists found that more than 5,000 sites on the genome of muscle cells had new methylation patterns, with some sites showing more methylation and some, less. The fascinating thing was that these changes only showed up in the exercised leg, not the control leg. It was a perfect experiment, same person, same diet, same sleep patterns, everything. Except that one leg got exercise and the other didn’t. Bottom line? The exercised leg appeared to show a slowing of the epigenetic clock.

Scientists who study the epigenetics of aging have made some other intriguing discoveries, too. As anybody can tell at a high school or college reunion, we don’t all age at the same rate. Despite having the same chronological age, in other words, we vary widely in the rate at which we age at the basic molecular level.

Indeed, some ethnic groups seem to age faster than others, according to epigenetic research. Men age faster than women. Even different tissues in the same body age at different rates. The heart, for instance, can be 50 years old, according to the epigenetic clock, and the lungs, 30.

DNA methylation can actually predict all-cause mortality, regardless of chronological age. In one 2016 study of 13,000 people, for instance, Horvath’s team showed that the epigenetic clock was able to predict the life spans of Caucasians, Hispanics and African-Americans “even after adjusting for traditional risk factors such as chronological age, gender, smoking, body-mass index, disease history, and blood cell counts.”

Some data even suggest that there is a 35 percent increase in the risk of death for each five-year increase in DNA methylation age.

Pretty sobering stuff, isn’t it? Makes you want to jump on one of those exercise bikes and pump away. With both legs, of course.

(Originally posted on Pyschology Today)

Okay, folks. It’s exercise-and-coronavirus time

To be honest, I was going to write about something totally different today.

But since we’re all cooped up for the foreseeable future and since our bodies (and minds) still need exercise, herewith some thoughts on how to get at least the minimum (30 minutes a day, five days a week) to keep from falling apart during this difficult time.

First, as you know if you’ve read my new book, Exercise Is Medicine, exercise has huge benefits for the immune system. Obviously, we need our immune systems more than ever these days.

You may have  heard over the years that exercise causes immune suppression. Well, banish that thought. Old studies of marathon runners seemed to suggest that intense exercise created an “open window” during which the immune system temporarily crashed and pathogens swooped in.

That’s a myth. True, the runners often did self-report sore throats. But that is wrong. When subjected to real, medical diagnoses, the intense exercisers who reported sore throats after exercise did not have infections at all, just irritated throats. No need to worry on that score.

The truth, which has been emerging steadily in recent years, even a single workout, far from making us more vulnerable to infection, can actually boost our immune systems. Indeed, the title of an important 2018 study from British researchers says it all: “Debunking the Myth of Exercise-Induced Immune Suppression…”

Writing in the journal Frontiers in Immunology, the authors say that, “to this day, research practice, academic teaching and even physical activity promotion and prescription continues to consider a prevailing myth that exercise can temporarily suppress immune function.” Dead wrong, they say. They conclude ‘that regular physical activity and frequent exercise are beneficial, or at the very least, are not detrimental to immunological health.”

Okay.

How do you do work out if you’re stuck in quarantine and your gym is closed. Well, one thing is obvious. Go outside. If you’re physically able to get outdoors and if you stay six feet away from other people on the street or in the park, by all means, do it. Walk. Run. Skip. Whatever. Breathe fresh air. Catch a few rays. Wave to the others from that respectful distance.

And if, for whatever reason you can’t go outside? Bounce around inside. Try to get your heart rate up enough so that you can talk but not sing. If you’re watching TV, stand up to watch. Pick up your cell and pace around while you’re chatting. If you live in an apartment building, walk or jog in the hallways provided you keep away from other hall-walkers. If you have no hallways, put on some music and dance. Channel those prisoners who keep sane by pacing around their cells. If nothing else, practice balancing on one foot while you wash the dishes.

Keep going. Do yoga on the floor. Swing your arms. Do sit ups. Use books or jugs of water as weights to pump iron.

Above all, don’t stay glued to the computer or TV all day. As I put it in my book, “Sitting kills.” Sure, it’s tempting to blob around since you’re home anyway, but don’t. If you are using this home-bound time to write that novel or do your taxes, that’s terrific. But get up at least once an hour and walk around.

Obviously, if you do catch the coronavirus and especially if you have a fever, take it easy. But otherwise, get up and move. Your body will thank you. So will your mind.

(Originally posted on Pyschology Today)

Here’s something to ponder: From an evolutionary biology point of view, is aging just one big accident?

The answer, surprisingly for those of us who assume that falling apart over time is the natural order of things, is Yes. Evolution didn’t “plan” for us to deteriorate in later life for the simple reason that evolution doesn’t “plan” anything. Rather, as bio-demographer S. Jay Olshansky at the University of Illinois puts it, aging “is an accidental byproduct of surviving beyond our biological warranty period, beyond fixed genetic programs that exist for growth, development, and reproduction.”

So what, then, does boost our chances for longer, healthier life? The main thing that is under our control, as I argue in my new book, Exercise is Medicine, is, of course, exercise. But other things help determine longer life, too, chiefly our genes and our environment. Let’s pause a moment to consider that. If you are born into an environment full of hazards, your chances for long-term survival are obviously poor, no matter how good your genes. If you’re born into a safe environment, your chances for long life improve.

And this feeds into the genetics. Over generations, if you grow up in a safe environment, you can afford to postpone the age at which you reproduce. This is key, because delayed age of reproduction helps select for genes that indirectly allow for or encourage longer life. In other words, if you’re healthy and safe enough to think about having babies – whether you’re a human or an opossum – in later life, you’ve probably already got good genes.

Think about what’s been going on with humans for decades now. All over the comparatively safe developed world, women are having children later. In the United States, the average age for the birth of a first child is now 26.3, up from 24.9 just a few years ago. Women whose biological clocks are ticking slowly enough that they are still capable of having a baby beyond age 33 are twice as likely to reach very old age as women who have their last baby at 29.

Worldwide, life expectancy has been steadily rising. Life expectancy at birth is now 68.6 around the world and is projected to rise to 76.2 by 2050. In the United States, life expectancy at birth for women in 2016 was 81.1, and for men, 76.1.

In other words, most of the increase in human longevity in recent times has to do with the fact that, in the developed world at least, we have made our environment safer, not that the process of aging itself has changed.

So what is that process of aging?

Not long ago, it wouldn’t have been possible to give a satisfying answer to that question. But in 2013, European scientists boiled down the most important changes to nine “hallmarks” of aging. This gets into some serious cell biology, but don’t panic. In future posts, we’ll make it accessible. For now, the take-home message is this: At least in the view of some researchers, the beneficial effects of aging affect all nine hallmarks of aging, in a positive direction.

Contrarily, our Westernized lifestyle – too much food and too little exercise – accelerates things in the wrong direction.

(Originally posted on Pyschology Today)

For most of us, aging feels inevitable, a more or less guaranteed downhill slide that we sometimes dread even more than death itself.

But one of the most fascinating things I discovered in the course of writing my new book on aging and exercise (Exercise is Medicine: How Physical Activity Boosts Health and Slows Aging) is that human aging is actually a kind of accident.

And while most of us think we know what aging is—the sagging skin, the shaky knees, the hunched back—I also discovered that to evolutionary biologists and other scientists who study aging, the process of aging is actually one of the deepest mysteries of the universe.

After all, what’s the point? Once you’ve passed your genes on to the next generation, why stick around? Why take up space and use food and other scarce resources? It’s the young who need those things to live to reproductive age. So why do old animals even exist? Or old people?

Evolution has no reason to favor long life, Steven Austad, a former lion tamer and now a bio-gerontologist at the University of Alabama at Birmingham, told me. Quite the contrary, he says: “Evolution favors early, copious reproduction at the expense of later life survival.”

S. Jay Olshansky, a biodemographer at the University of Illinois, Chicago, puts it this way: “We age because Mother Nature turns her back on us once we’re in the post-reproductive region of the lifespan. Natural selection didn’t build in a program to make us fall apart later in life.”

And yet here we are, a world with growing numbers of old people, even very, very old people. Was it “supposed” to be this way? Come to think of it, why is there even such a thing as menopause? Why do women live 30, 40, 50 years past reproduction? (There’s less of a question about old men—some can produce viable sperm until the day they die, though getting it to its proper destination can get iffy).

Perhaps, as one school of thought suggests, aging exists because old animals—especially females—provide evolutionary advantages, not to the old animal herself, but to her offspring and genetic relatives. It’s the so-called “grandmother effect.”

“If you are a human female, and you are taking care of your grandchild… your act of taking care of your grandchild is a reproductive act,” at least in the eyes of evolutionary biologists, Michael Rose, a professor of ecology and evolutionary biology at the University of California, Irvine, told me.

Actually, grandfathers are sometimes just as important as grandmothers, because they, too, share food, and sharing is evolutionarily crucial, says Harvard University evolutionary biologist Daniel Lieberman.

A hunter-gatherer mother requires enough calories to sustain not just her own body, but the bodies of her children as well, Lieberman notes, which means that hunter-gatherer females who are lactating and caring for young children struggle to get enough energy.

“But grandmothers and grandfathers are unencumbered—they can produce a surplus,” he says. “And that energy goes toward the family. As soon as humans started sharing, there was a strong selective pressure for longevity.” (Longevity, as we’ll soon see, is also fostered by “nice” environments, with lots of food around.)

Among other things, older animals are handy because they know where to find long-forgotten watering holes or food supplies. Female post-menopausal killer whales (orcas) are terrific resources for their tribe—they know where scarce salmon are and are often the ones who lead others to food when supplies are low.

Old female elephants are great resources, too. In fact, elephant societies are famously matriarchal, with older females helping their herds survive droughts, food scarcity, poachers, and, of course, lions.

Some traditional human societies with long-lived men and women show a similar pattern, as Jared Diamond writes. Jared is a professor of geography at the University of California, Los Angeles, who, for more than 50 years, has studied New Guinea farming societies.

To be sure, he says, nomadic hunter-gatherer societies aren’t always kind to old people, who may be cast out to die or simply left behind if they can’t keep up with the group’s wandering.

But in traditional sedentary societies, old folks are valuable. “In traditional societies without writing, older people are the repositories of information,” Diamond says. “It’s their knowledge that spells the difference between survival and death for their whole society in a time of crisis caused by rare events for which only the oldest people alive have had experience.”

That’s exactly what happened in 1993 when an outbreak of the hantavirus triggered a spate of deaths on the Navajo reservation in the Four Corners area of the American Southwest. The virus, originally, and unfairly, dubbed the “Navajo flu” and since renamed the Sin Nombre (No Name) virus, is carried by deer mice. When the feces of deer mice dry up and become aerosolized, humans can unknowingly breathe the contaminated dust and come down with often-fatal pulmonary infections.

When the outbreak hit, scientists from New Mexico’s health department and the federal Centers for Disease Control and Prevention flocked to the Navajo reservation to study the virus. But it was their wise decision to talk with Navajo elders that cracked the case.

The Navajo elders remembered that twice before in the 20th century, they had observed a connection between increases in rainfall, a booster crop of pinyon nuts, and a surge in the deer mouse population. In 1993, those exact conditions pertained—unusually heavy rains, lots of snowmelt, huge quantities of pinyon nuts, a surge in deer mice, and a not-new-after-all epidemic deciphered by the oldest folks around.

Clearly, then, there are some benefits for the group as a whole to have older animals or people around. But, as we’ll see in the next blog, that can’t be the whole story.

(Originally posted on Pyschology Today)

“If you run a young pig on a treadmill, the bones get bigger,” says Mark Hamrick, Ph.D., a muscle and bone researcher from Georgia. “But not an old pig.” And what’s true for pigs, alas, is true for humans as well.

On the bright side, even though exercise can’t build bone in later life, we can use exercise, especially high-impact, weight-bearing exercise, to help preserve the bone we’ve got left.

It’s abundantly clear that exercise in youth builds strong bones, and that this benefit sticks around for quite a while. Compared to sedentary folks, for instance, people who were elite athletes in their youth have greater bone mass and bone strength later on, even if they’ve stopped training.

Jumping, in particular—think cheerleaders—has been shown to boost bone density in young people. In one study involving premenopausal women, jumping 20 times with a 30-second rest between jumps and doing this twice daily can boost bone density to some degree. A different study of premenopausal women involving both jumping and weightlifting also showed some increased bone density.

But what, if anything, these data mean for older women is unclear.

A 2009 Spanish review of the research suggested that while high-impact exercise can enhance bone mass, this is not true in postmenopausal women, precisely the group most prone to osteoporosis and fractures.

On the other hand, British researchers found that both young and older women who performed brief bursts of high-intensity, weight-bearing exercise had stronger bones than those who didn’t. But this study showed a simple association, not causality.

Randomized, controlled studies have been largely discouraging. A 2006 randomized study found that moderate-intensity aerobic (not resistance) training did nothing for bone mineral density. A 2017 randomized study of resistance and aerobic training also found no effect on bone mineral density, though this study was in breast cancer survivors who were taking estrogen-blocking medication.

In other words, exercise can’t build bone in older people, but it can help preserve bone, as a 2017 systematic review and meta-analysis of 11 randomized trials involving more than 1,000 postmenopausal women showed.

A different 2017 systematic review of 10 randomized studies also showed that high-impact exercise preserved bone density in both peri-and postmenopausal women. Interestingly, this study looked not just at exercise but at standing on a vibrating platform, which also helped preserve bone.

Granted, it may seem like cheating to exercise purists, but other research also suggests that standing on vibrating platforms may boost bone density. In a 2013 Taiwanese study of postmenopausal women, six months of standing on a vibrating platform for five minutes three times a week yielded about a 2% increase in lumbar spine bone density.

As for me, I am one of those exercise purists. True, I can’t do all those flips and cartwheels and jumps of my youth, but I can still jog, swim, lift weights, and crank through 50 minutes several times a week on an elliptical machine.

It may take longer—and take more motivation—but for me, at least, genuine exercise is a lot more fun.

(Originally posted on MindBodyGreen)

It’s not just that physical activity is good for you. It’s that a sedentary lifestyle, as a totally separate variable, is seriously bad. [i] [ii] [iii] [iv] [v] [vi] 

Sitting too much – all by itself – can raise the risk of disease and premature mortality, even if you dutifully exercise.[vii]In fact, many well-educated people do exercise; but they’re also more likely to have desk jobs.[viii]

A large 2012 study of 240,819 healthy American adults, for instance, showed that more time spent sitting was linked to premature death from heart disease and cancer.[ix] Even among people who exercised more than seven hours a week, watching TV for more than seven hours a day was linked to a 50 percent greater risk of all-cause mortality and a 2-fold greater risk of cardiovascular mortality.

You may be able to offset this somewhat with activity.[x] [xi] But to wipe it out completely, you have to work out hard for an hour or more every day, as a 2016 study in The Lancet showed.[xii]

That study, a meta-analysis of 13 studies involving more than 1 million people, showed, as expected, that people who sat for 8 hours a day and got almost no exercise had higher mortality rates than people who sat less and were very active. The good news was that sitting for 8 hours a day was not associated with higher death rates if people were very active – meaning 60 to 75 minutes of hard exercise a day.

Put bluntly, sitting kills. If you want a short, sickly life, just sit there, for 13 hours a day, like the average American.[xiii](In Western countries overall, adults spend 55 to 70 percent of the day – 9 to 11 hours – just sitting.[xiv])

Before you give up in despair, though, contemplate this. Replacing just two minutes of sitting every hour with a bit of moving around helps mitigate the risks of sitting. Better yet, don’t sit for more than 30 minutes at a stretch.[xv] [xvi][xvii] [xviii]

The main idea here is that sedentary behavior is not just the absence of physical activity but a distinct behavior with its own health risks.[xix] [xx] [xxi] [xxii] [xxiii]

In fact, “sedentary physiology” is now considered a separate field of research from the long-established field of “exercise physiology.”[xxiv]

Technically, sedentary behavior is defined as any waking behavior characterized by an energy expenditure less than or equal to 1.5 times the resting metabolic rate while in a sitting or reclining position. (Scientists measure activity in “METS,” or metabolic equivalents. One MET is the amount of energy it takes to sit still; moderate activity burns three to six METS; vigorous activity burns more than six.[xxv])

That’s different from physical inactivity, which is defined as not reaching the recommended 150 minutes per week of moderate intensity exercise.[xxvi]

Physical inactivity, in fact, is believed to be “the biggest public health problem of the 21^st century,” says Steven N. Blair, a professor of exercise science and epidemiology/biostatistics at the University of South Carolina.[xxvii]

Indeed, physical inactivity causes as many deaths a year globally as smoking.[xxviii]

Bottom line: Don’t just giving up smoking as we head into 2020. Giving up sitting around, too. Your life depends on it.

[i] Bouchard, C., Blair, S. N., & Katzmarzyk, P. T. (2015). Less Sitting, More Physical Activity, or Higher Fitness?. Mayo Clinic Proceedings, 90(11), 1533–1540.

[ii] Proper, K. I., Singh, A. S., van Mechelen, W., & Chinapaw, M. J. M. (2011). Sedentary behaviors and health outcomes among adults: a systematic review of prospective studies. American Journal of Preventive Medicine, 40(2), 174–182.

[iii] Thorp, A. A., Owen, N., Neuhaus, M., & Dunstan, D. W. (2011). Sedentary behaviors and subsequent health outcomes in adults a systematic review of longitudinal studies, 1996-2011. American Journal of Preventive Medicine, 41(2), 207–215.

[iv] Das, P., & Horton, R. (2016). Physical activity-time to take it seriously and regularly. Lancet, 388(10051), 1254–1255.

[v] Sallis, J.F., Bull, F., Guthold, R., Heath, G.W., Inoue, S., Kelly, P….Hallal, P.C., (2016). Progress in physical activity over the Olympic quadrennium. The Lancet, 388(10051), 1325–1336.

[vi] Reis, R. S., Salvo, D., Ogilvie, D., Lambert, E. V., Goenka, S., Brownson, R. C., & Lancet Physical Activity Series 2 Executive Committee. (2016). Scaling up physical activity interventions across the globe: stepping up to larger and smarter approaches to get people moving. Lancet, 388(10051), 1337–1348. 

[vii] Craft, L. L., Zderic, T. W., Gapstur, S. M., VanIterson, E. H., Thomas, D. M., Siddique, J., & Hamilton, M. T. (2012). Evidence that women meeting physical activity guidelines do not sit less: An observational inclinometry study. The International Journal of Behavioral Nutrition and Physical Activity, 9, 122.

[viii] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health, Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/

[ix] Matthews, C. E., George, S. M., Moore, S. C., Bowles, H. R., Blair, A., Park, Y., … Schatzkin, A. (2012). Amount of time spent in sedentary behaviors and cause-specific mortality in US adults. The American Journal of Clinical Nutrition, 95(2), 437–445.

[x] Katzmarzyk, P. (personal communication, August 9, 2016).

[xi] Duvivier, B.M.F.M.,  Schaper, N.C., Hesselink, C., van Kan, L., Stienen, N., Winkens, B. (2017). Breaking sitting with light activities vs. structured exercise: a randomized crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes. Diabetologia, 60 (3), 490-8.

[xii] Ekelund, U., Steene-Johannessen, J., Brown, W. J., Fagerland, M. W., Owen, N., Powell, K. E., … Lancet Sedentary Behaviour Working Group. (2016). Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet (London, England), 388(10051), 1302–1310.

[xiii] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health. Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/

[xiv] Matthews, C. E., Chen, K. Y., Freedson, P. S., Buchowski, M. S., Beech, B. M., Pate, R. R., & Troiano, R. P. (2008). Amount of Time Spent in Sedentary Behaviors in the United States, 2003–2004. American Journal of Epidemiology, 167(7), 875–881.

[xv] Diaz, K.M., Howard, V.J., Hutto, B., Colabianchi, N., Vena, J.E., Safford, M.M. (2017). Patterns of sedentary behavior and mortality in U.S. middle-aged and older adults: A national cohort study. Ann Intern Med, 167 (7), 465-75.

[xvi] Beddhu, S., Wei, G., Marcus, R. L., Chonchol, M., & Greene, T. (2015). Light-Intensity Physical Activities and Mortality in the United States General Population and CKD Subpopulation. Clinical Journal of the American Society of Nephrology: CJASN, 10(7), 1145–1153.

[xvii] Reynolds, G. (2015, May 13). A 2-minute walk may counter the harms of sitting. The New York Times. Retrieved from https://well.blogs.nytimes.com/2015/05/13/a-2-minute-walk-may-counter-the-harms-of-sitting/

[xviii] Preidt, R. (2016, August 16). Even if you exercise, too much sitting time is bad. CBS News. Retrieved from http://www.cbsnews.com/news/even-if-you-exercise-prolonged-sitting-time-is-bad-for-heart-health/

[xix] Pulsford, R. M., Stamatakis, E., Britton, A. R., Brunner, E. J., & Hillsdon, M. (2015). Associations of sitting behaviours with all-cause mortality over a 16-year follow-up: the Whitehall II study. International Journal of Epidemiology, 44(6), 1909–1916.

[xx] Pate, R. R., O’Neill, J. R., & Lobelo, F. (2008). The evolving definition of “sedentary.” Exercise and Sport Sciences Reviews, 36(4), 173–178.

[xxi] Young, D. R., Hivert, M.-F., Alhassan, S., Camhi, S. M., Ferguson, J. F., … Yong, C. M. (2016). Sedentary Behavior and Cardiovascular Morbidity and Mortality: A Science Advisory From the American Heart Association, Endorsed by the Obesity Society. Circulation, 134(13), e262–e279.

[xxii] Althoff, T., Sosic, R., Hicks, J.L., King, A.C., Delp, S.L. & Leskovec, J. (2017). Large-scale physical inactivity data reveal worldwide activity inequality. Nature, 547 (7663), 366-39. 

[xxiii] Dunlop, D. D., Song, J., Arntson, E. K., Semanik, P. A., Lee, J., Chang, R. W., & Hootman, J. M. (2015). Sedentary time in U.S. older adults associated with disability in activities of daily living independent of physical activity. Journal of Physical Activity & Health, 12(1), 93–101.

[xxiv] Tremblay, M. S., Colley, R. C., Saunders, T. J., Healy, G. N., & Owen, N. (2010). Physiological and health implications of a sedentary lifestyle. Applied Physiology, Nutrition, and Metabolism, 35(6), 725–740.

[xxv] Measuring Physical Activity. (2016). Harvard T.H. Chan School of Public Health. Retrieved from https://www.hsph.harvard.edu/nutritionsource/mets-activity-table/

[xxvi] Bouchard, C., Blair, S. N., & Katzmarzyk, P. T. (2015). Less Sitting, More Physical Activity, or Higher Fitness?. Mayo Clinic Proceedings, 90(11), 1533–1540.

[xxvii] Blair, S. (2009). Physical inactivity: the biggest public health problem of the 21^st century. Br J Sports Med, 43, (1).

[xxviii] Lee, I.M., Shiroma, E.J., Lobelo, F., Puska, P., Blair, S.N., & Katzmarzyk, P.T. (2012). Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. The Lancet, 380(9838), 219-229.

[xxix] Lee, I. M. (personal communication, July 21, 2016).

[xxx] Levine, J. (2014, November 1). Killer Chairs: How Desk Jobs Ruin Your Health, Scientific American. Retrieved from https://www.scientificamerican.com/article/killer-chairs-how-desk-jobs-ruin-your-health/

[xxxi] Lee, I.-M., Shiroma, E.J., Evenson, K.R., Kamada, M., LaCroix, A.Z., Buring, J.E.  (2017). Circulation, 136 (19).