Eat right and exercise — it's a mantra doctors have been drilling into people for years. It's also a tired refrain that most people probably tune right out. But an astonishing accumulation of research in recent years shows that exercise alone can add years and years to your lifespan — and that indolence and overeating are potentially far more fatal than anyone could have imagined.
When it comes to death and disease, "sitting is the new smoking," warned Dr. Jeanne Marrazzo, a professor of allergy and infectious diseases at the University of Washington's School of Medicine in Seattle. Rivaling tobacco use as a killer, "physical inactivity causes nearly 1 in 10 deaths worldwide, or over 5 million excess and preventable deaths each year."
Marrazzo was speaking at the annual Conference on World Affairs, a weeklong forum on global issues held at the University of Colorado in Boulder. She was the first panelist at an April 9 session on health and exercise titled "Walk, Bike, Dance, Bend, Stretch and Run for Your Life."
Marrazzo did not mince her words: "I see a lot of critically ill people," she told the gathering, "and the number-one predictor of mortality is obesity."
A related predictor, she added, is metabolic syndrome, a group of risk factors that raises the chance for heart disease, stroke, diabetes and other diseases — factors such as a large waistline, high blood pressure and too much fat in the blood (triglycerides). Inactivity combined with too much fat — or the wrong kind in the wrong place, such as your belly — make for a "metabolic disaster," Marrazzo said.
Simply sitting for hours, whether working at a desk, watching television or driving a car — they very things most of us do each day — can have a huge impact on how long we live and how well we live. More surprisingly, your risk doesn't diminish with regular exercise, which can't undo the damage done by being sedentary for long periods of time.
In February 2014, Dorothy Dunlop, a professor of medicine at Northwestern University, drew attention to the notion of "sitting disease" by demonstrating that sitting eight to 10 hours a day after the age of 60 puts you at risk of disability regardless of how much exercise you get. Dunlop found that every additional hour adults over 60 spend sitting increases their risk — by a stunning 50 percent — of being disabled for common daily activities such as bathing and dressing.
Similarly, in 2013, Richard Rosenkranz of Kansas State University along with researchers in Australia found that people who sit for more than four hours a day are more likely to develop cancer, diabetes, heart disease and high blood pressure no matter their height, weight, age, income, education or physical activity levels.
Harold Kohl, a researcher at the University of Texas School of Public Health and lead author of a study suggesting that physical inactivity should be recognized as a global pandemic, said the importance of exercise deserves more notice.
"The role of physical inactivity continues to be undervalued despite robust evidence of its protective effects," he wrote. "The effect of this tardiness has been to put physical activity in reverse gear compared with population trends and advances in tobacco and alcohol control and diet."
There has been some movement on the issue — but not enough. Sales of so-called standing desks soared in the wake of this "sitting disease" phenomenon, but breaking up sitting with standing doesn't help much, according to a March 2014 article in Sports Medicine Australia: Instead, you have to move or walk around to achieve real health benefits.
It seems like such a simple prescription for so many complicated ailments — just get up and move. But the benefits of simple, moderate physical activity should not be discounted or minimized. They are real and far-reaching — as are the dangers of sitting around doing nothing.
Jenny Seham, another panelist at the Conference on World Affairs, described the power of simple movement by recounting a personal story. Seham is a dancer and assistant professor of psychiatry at the Montefiore Medical Center in New York City.
"A man walks into his neurologist's office with his wife — with difficulty," she said. "He has had Parkinson's for 10 years. The doctor says to his wife, 'Has your husband been using his wheelchair?'
"The man replies, 'No, doctor, I wake up two hours early, struggle to get dressed, walk to the bus stop, struggle to get on the bus, the bus takes me to 42nd Street and Times Square, where I get off the bus and walk to my office. At then at the end of my work day I walk back.'
"The doctor says, 'That's off the chart — you shouldn't be able to walk anymore.' And the man replies, 'Well, it's a good thing I didn't read that chart.'
"That man was my father," Seham revealed. "He passed away in 2006, was active until then, and was indeed off the Parkinson's chart. He taught us the value of exercise."
Research done by the Cleveland Clinic in November 2012 shows how ahead of his time Seham's father was. Clinic neuroscientist Jay Alberts used brain scans to look at connections between brain regions before and after Parkinson's patients underwent bicycle exercise sessions three times a week for eight weeks. Their brain connections visibly improved after exercise, his scans demonstrated, and faster pedaling created more significant results.
Other exciting research is equally revealing: Researchers in Taiwan found that exercise reversed age-related cell loss in the brain's hippocampus, restoring the production of new neurons in middle-age mice.
But how can the hands of time be turned back? In 2013, Harvard Medical School researchers led by Bruce Spiegelman uncovered one possible explanation. They found that during endurance exercise, a hormone called irisin is produced in the brain that improves cognitive function and protects the brain against degeneration, turning on genes involved in memory and learning.
We've long known that fat cells pump inflammation chemicals into the body, but now we're learning that exercise can tamp this mechanism down. This past February, researchers at Georgia Regents University in Augusta showed that a fat-generated protein caused brain damage and cognitive deficits in obese mice, but treadmill training alone prevented or reversed both events. That is, exercise neutralized the inflammation, normalizing damaged neurons and improving memory in obese mice.
Moving from mice to men and women has also led to promising results. In 2013, J. Carson Smith of the University of Maryland at College Park linked exercise to better cognition in people at risk for Alzheimer's disease: Twelve weeks of exercise on a treadmill improved thinking and memory in adults with mild cognitive impairment.
"No study has shown that a drug can do what we showed is possible with exercise," Smith said.
Exercise works wonders for brains of all ages, although mechanisms differ by age group and activity. Long-term aerobic exercise in young adults 18 to 30 improved both working memory capacity and cognitive control in thinking tasks, according to research published this March by the University of the Balearic Islands in Spain.
Studies have also shown that short-term and long-term exercise trigger different results. Brief, intense bursts of exercise bring blood to the brain along with more endorphins and neuron activity. In contrast, long-term exercise routines create permanent brain change, including higher levels of new neurons, stronger learning capacities and bigger brain reserves.
Perhaps most arresting of all, researchers in Montreal and San Diego found that as little as 20 minutes of moderate exercise three times a week during pregnancy enhances the newborn brain. "The simple act of exercising during pregnancy could change your child's future," said study leader Dave Ellemberg of the University of Montreal.
Exercise can also affect widespread mental disorders found throughout a person's lifetime. Anxiety, depression and schizophrenia have all been to shown to respond positively to physical activity. For example, research presented at an American College of Sports Medicine meeting in Denver in 2011 found that 60 percent of study participants with generalized anxiety disorder got rid of their anxiety through a weight-training group — as did 40 percent of those doing aerobics. That year, researchers at the University of Texas Southwestern Medical Center also found that daily exercise can help depressed people whose symptoms aren't relieved by a single antidepressant, working just as well as adding a second drug would.
Christopher Douglas says he doesn't need studies to convince him of the effects of exercise on the brain. An expert rock climber, Douglas is a mathematics professor at Oxford University, where he co-founded the Centre for Quantum Mathematics and Computation.
"I want to focus on the mental aspects of exercise," Douglas said at the University of Colorado conference, "and my reaction to our panel title is this: What are we running from? I think many people who exercise are running from their thoughts and the mind's supremely evolved capacity for analytical chatter. Running is one way to calm it. It doesn't eliminate the chatter but it does focus it."
On that note, Douglas said that different forms of exercise test the brain in different ways. With running, the mind often rebels against the pain of jogging long distances. "But every time you don't listen to it [and] push yourself through discomfort," Douglas said, you gain "surprisingly useful skills in other aspects of life."
Skiing is very different, he said. "If you drop into dense forests to ski, you have to react much more quickly than you can think so you don't hit a tree. Thinking is a fairly slow process but physical reactions can be faster." This requires laser-like focus, "which forces the mind to shut up."
"Climbing generates an entirely different way of inhabiting the territory between the body and the mind," Douglas observed. "By instinct you hold on by your fingertips but unlike skiing, it's a very slow and methodical process and one of self trust. Social dance? That's a shared mental space between two people, while yoga is the sport most explicit about guiding your thoughts and quieting your mind."
From Brain to Body
As Douglas's comparisons suggest, exercise is a whole-body experience. It has been shown to help heal damaged nerve cells in the retina and slow the progression of macular degeneration, for instance, while weight-bearing exercise improves bone health, which starts to deteriorate after the age of 30.
But some of its most important and life-saving effects come from its impact on arteries, veins and the blood-pumping heart. For decades, the American Heart Association has recommended exercise to improve heart and vascular health, including for patients with peripheral artery disease (PAD).
But until recently the range and sophistication of the exercise effect, not to mention the details of how exactly it works, have been obscure. Now, a Harvard Medical School study led by Zoltan Arany has shown that exercise counters the narrowed arteries and reduced blood flow of PAD by triggering a chemical cascade that increases the supply of a particular molecule. This molecule senses circulation problems, spurs blood vessel growth and brings new blood to leg muscle.
"Even the best medical therapy available is less effective against PAD than simply walking daily," Arany concluded.
Separately, researches have discovered that exercise helps heart failure patients by reducing inflammation and muscle wasting while improving strength and oxygen uptake.
Exercise is also key to curbing the risk factors associated with metabolic syndrome. A person who has metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone who doesn't have the syndrome.
A University of Mexico and New Mexico Veterans research program reported that exercise doubled the benefits of a weight-loss program for adults with metabolic syndrome. Exercise alone helped patients with type 2 diabetes, according to work conducted at Leiden University Medical Center in the Netherlands. Even with no changes in diet, six months of exercise that included endurance and resistance sessions led to a significant decrease in dangerous fat in the abdomen, liver and around the heart.
Regular activity has also been found to reduce cancer risks for women, particularly with breast and colon cancer, and improve the quality of life for all cancer patients, both during and after treatment.
Clearly, getting moving is in your best interest. Sitting is a necessary evil in today's world of cubicles and long commutes, but that doesn't mean we can't take easy steps to break the rut of our sedentary lifestyles. These can be as simple as walking around the house when a commercial comes on the TV or just taking a break from the computer every hour to walk around the office. In a world of increasingly sophisticated medical treatments, it almost sounds trite to offer up walking as a cure-all for disease. But movement really is what keeps us — and our health — going.
About the Author
Carolyn Cosmos is a contributing writer for The Washington Diplomat.
Last Edited on May 1, 2014