Former President Jimmy Carter pursuing health in 1978; politics aside, accumulating evidence indicates a commitment to fitness helped him remain active and lucid well into his 90s/Wikimedia Commons

Confronting the Epidemic of Sloth

Physiologists, epidemiologists and big-data miners have been combing through the United Kingdom’s Biobank again, and it appears they may have come up with an answer to a question posed by Australian doctors a  year ago:

‘If exercise is medicine, why don’t we know the dose?”

After looking at “accelerometer data” from 81,717 Biobank participants, a significantly large sample size, the scientists reporting last week in JAMA (formerly the Journal of the American Medical Association)  say the answer appears to be a daily dose of at least 20 minutes of  “moderate to vigorous physical activity.”

Most Americans these days don’t get 20 minutes of aerobic exercise per day at any level, let alone 20 minutes of vigorous activity. The Centers for Disease Control reports 53.1 percent of Americans fail to meet the national, minimum standard of 150 minutes per week of “moderate” exercise or 75 minutes per week of “vigorous exercise.”

Those numbers work out to 21 minutes and 25 seconds per day for “moderate” exercise or 10 minutes and 43 seconds per day for “vigorous” exercise, and the amount of exercise actually taking place is likely over-reported in the CDC summary given the source of the information.

The results come from the  2020 National Health Interview Survey which gathers its data from personal household interviews. Social desirability bias – the problem of people shading their answers toward that which is socially preferred  – is a big confounder in such studies.

When answering questions about sensitive health behaviors, such as those touching on quantities of alcohol consumed or how much exercise performed, people have a bad habit of fudging their answers toward what they are expected to do rather than what they actually do.

But even without accounting for this bias, the evidence is clear that there is now an American Epidemic of Sloth, and it is costly to both people and the nation’s health care system. This was already known to a significant degree before the latest study.

Lack of exercise has been previously and clearly  linked to increased risks of heart disease, the world’s number one killer; some cancers, dementia and other so-called “chronic diseases.”

A peer-reviewed, 2012 study by U.S. and Danish researchers involved in metabolic research went so far as to declare that “physical inactivity is a primary cause of most chronic diseases.

“Overwhelming evidence proves the notion that reductions in daily physical activity are primary causes of chronic diseases/conditions and that physical activity/exercise is rehabilitative treatment from the inactivity-caused dysfunctions.”

Starting point for many diseases

The latest research goes beyond that to offer evidence that health problems among the unfit aren’t limited to chronic diseases.

“In this cohort study using accelerometer data from 81,717 UK Biobank participants,” the researchers reported, “higher levels of physical activity, particularly moderate to vigorous intensity activity, were associated with lower risks of hospitalization for nine of the 25 most common reasons for hospitalization. The largest decreases in risk were for gallbladder disease, diabetes, and urinary tract infections.”

The other diseases against which exercise offered some protection were venous thromboembolism, pneumonia, ischemic stroke, iron deficiency anemia, diverticular disease and colon polyps.

The latter might be linked to the amount of time food spends in the digestive tract. Various studies have found that the time it takes food to move through the bowels appears to be tied to the worst of colon problems – colorectal cancer – and a phenomenon known as “runners trots” is well known for speeding what doctors call the “transit time” through the bowels of those who exercise vigorously. 

The latest research to specifically address this subject, published in a peer-reviewed study in the British Journal of Cancer in 2021, concluded that “physical activity can reduce the bowel transit time and therefore reduce the time of contact between carcinogens and colonic mucosa.”

The researchers involved in that study reported the rather astonishing finding “that if individuals replace daily sedentary behavior with 20 to 90 minutes of moderate-to-vigorous physical activity (MVPA) or with 13 to 60 minutes of accumulated MVPA, their risk of colorectal cancer will decrease by 40 percent.”

Researchers involved in the JAMA study published last week did not look specifically at cancers like this or at heart disease because, as they noted, higher physical activity levels have already been well “associated with lower risks of cancer, cardiovascular disease, and diabetes, but associations with many common and less severe health conditions are not known.”

They are now.

Get moving

The latest study documented that getting people up off the couch and moving results in “lower risks of hospitalization across a broad range of health conditions. These findings suggest that aiming to increase MVPA by 20 minutes per day may be a useful nonpharmaceutical intervention to reduce health care burdens and improve quality of life.”

The study, unfortunately, did not look at exercise’s association with the hot-button disease of the day – Covid-19 – but an earlier study of 412,596 Biobank participants did as reported here when the results first appeared on the MedRxiv preprint server in 2020. That study has since been peer-reviewed and published in the International Journal of Obesity. 

Nothing changed.

“Slow walkers” still have a risk of severe Covid-19 or death near two and a half to almost four times greater than “fast walkers,” walking pace being a simple, fundamental measure of aerobic fitness. Researchers concluded after that study that slow walkers were identifiable as “a high-risk group for severe COVID-19 outcomes independent of obesity.”

Many of them are likely now dead. Since the pandemic began, there has been a lot of attention paid to the development of vaccines and little attention paid to improving the fitness of Americans which is increasingly being shown to have across-the-board physical health benefits.

But wait, there’s more.

There might be even bigger mental health benefits than physical health benefits in a nation rapidly aging. A variety of recent studies have shown exercise significantly slows the loss of cognitive function with age and helps prevent dementia.

“Several prospective studies have looked at middle-aged people and the effects of physical exercise on their thinking and memory in later life,” the Alzheimer’s Society says. “Combining the results of 11 studies shows that regular exercise can significantly reduce the risk of developing dementia by about 30 percent. For Alzheimer’s disease specifically, the risk was reduced by 45 percent.”

There are even greater benefits when exercise is combined with other healthy, lifestyle behaviors.

“One particular study looked at health behaviors of over 2,000 men in Wales, and followed them for 35 years,” the Society said. “Of the five behaviors that were assessed (regular exercise, not smoking, moderate alcohol intake, healthy body weight and healthy diet), exercise had the greatest effect in terms of reducing dementia risk. Overall, people who followed four or five of the above behaviors were up to 60 percent less likely to develop dementia.”

These non-pharmaceutical interventions can claim more success than the drugs now the market to treat dementia, and best of all,  adopting a healthy lifestyle and exercising is free. If you look at the cost of cigarettes these days, it’s clear the non-pharmaceutical interventions or NPIs as everyone started calling them during the pandemic can actually save you considerable money.

Drug companies are making some progress in treating dementia, but it has been slow. There is hope for a new drug called Lecanemab, but the results of a clinical trial published in the peer-reviewed New England Journal of Medicine in January did not make it look like a successful moon shot.

“Lecanemab reduced markers of amyloid in early Alzheimer’s disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events,” the study concluded. “Longer trials are warranted to determine the efficacy and safety of lecanemab in early Alzheimer’s disease.”

Though some, probably many Americans, see drugs as solutions to all that ails us, they are not always the solution as Covid-19 vaccines have shown. The virus is still spreading despite widespread vaccination, and though vaccinations significantly reduce the risk of death, especially among the fit, vaccinated people are still dying.

Not a new problem

While President Joe Biden likes to capitalize on late President John F. Kennedy’s “moon shot” speech of 1962 by calling for new moon shots to cure the country’s deadliest diseases, another old – not to mention cheap – JFK initiative seems to have been largely forgotten.

More than six decades ago, Kennedy recognized the declining fitness of Americans and tried to do something about it.

“After World War II, many Americans worried that US citizens, especially the young, were growing overweight and out of shape,” the JFK Library recounts. “The nation’s economy had changed dramatically, and with it the nature of work and recreation changed. Mechanization had taken many farmers out of the fields and much of the physical labor out of farm work. Fewer factory jobs demanded heavy labor. Television required watching rather than doing. Americans were beginning to confront a new image of themselves and their country, and they did not always like what they saw.”

Kennedy’s predecessor, the late President Dwight D. Eisenhower, a former five-star general, had first tried to take action in the mid-1950s, but ran into considerable blowback from those, as the JFK Library fairly describes them, who believed “the idea of the nation’s youth constrained by a state-ordered fitness program seemed a little ‘red,’ even fascist.”

Eisenhower’s plan fizzled in the face of those Cold War fears.

Kennedy managed to jump-start it and for a while, his 50-mile-hike challenge became something of an American “thing.” Then Kennedy was assassinated, the eighth fattest president in American history – Lydon Baines Johnson – plopped his butt down in the White House, and it’s pretty much been downhill on the fitness front ever since despite the election of a variety of fitter presidents.

Presidents George W. Bush, Barack Obama, the late Ronald Reagan, Biden, Jimmy Carter and the late Richard Nixon (listed in order of descending weight) all weighed less than the historical average of 188.85 pounds for U.S. presidents, according to the website Statista. And at least three of them – Bush, Obama and Carter – were highly active. Gold’s Gym put Bush and Carter numbers two and four on its top-10 list of fittest presidents in 2008, and Obama was well known for his active lifestyle.

None of them, unfortunately, did much more than talk about getting Americans moving.

During the “energy crisis” of 1979, Carter did tell the country it was time to “stop talking and start walking,” but his crisis responses were largely aimed at improving mass transit and boosting automobile mileage, which over the long term just served to make the health of Americans worse.

Americans kept moving away from cities into suburbia because they could afford to and today the U.S. Census Bureau reports the average American spends almost an hour per day on his or her butt in a car commuting to work where she or he, thanks to the wonders of technology in front of your face at this very moment, spends 6.5 hours sitting in front of a computer screen, according to a survey conducted for contact lenses manufacturer Acuvue in 2018.

This amounts to about seven and a half hours of work-related sitting for the average American, who later spends about three hours more per day sitting and watching TV, according to Statista. That is down from a peak of almost three a half hours in 2018, but the change is largely attributable to a lot more time spent sitting and staring at a computer screen.

A Verizon study concluded Alaskans spend a nation-leading, 2 hours and 46 minutes of personal time staring at a computer screen, although the national average for “leisure viewing” was but an hour and a half. Still, the vast majority of this time is spent sitting.

Do the math: An hour in the car, plus 6.5 hours at work, plus 3 hours in front of the TV, plus 1.5 hours in front of the computer equals about 12 hours spent sitting. A Yale School of Medicine study concluded this is a good way to get to the grave early.

“The study showed that sitting for 8 or more hours per day was linked to a roughly 20 percent higher risk of getting heart disease or dying from any cause over the study period, compared to those who sat for only half that time” is how WebMD summarized the results.

“Even sitting for 6 to 8 hours daily was associated with a 12 percent higher risk of early death and a 13 percent higher risk of heart disease. This was true for people living in high-income, middle-income, and low-income countries.

“The health benefits of being physically active were also clear in the study. People who sat the most and were the least active had the highest risk (up to 50 percent greater risks), but for people who sat the most and were active, the risk was only 17 percent.”

This country needs a moon shot all right. It needs a get-up-off-your-ass-and-move moonshot. But instead many Americans are talking about the need for “fat acceptance as social justice” when obesity is usually, although not always, one of the most obvious signs of people not getting enough exercise.