November 13, 2017
post-page-1.jpg

Dick Talens

Being healthy is simple, right? “Eat less, move more.” That’s easy to say, but practicality is one of the most important things when it comes to health and fitness. Recommendations like this are blanket statements that don’t address practicality—so when it comes down to it, which is more important? Diet, or exercise?

Yes, we should all eat healthier. Yes, we should exercise every day. There are infinite things we could do in order to be healthier, like sit less, eat more vegetables, eat less processed food, or drink less alcohol. But they don’t take into account the reality of life: we are all constrained by a finite amount of resources such as time, energy, willpower, and money. Recommendations that don’t take this into account can easily make us feel like we are failing our fitness and health goals.

To give you a sense of the importance of practicality, consider this recent meta-study (i.e. a study of studies), published in the Journal of the American Medical Association, which sought to figure out “which diet works best?” by looking at the results of 59 individual studies. These studies included various nutritional recommendations, such as low-fat, low-carb, and so on. Which of these recommendations reigned king? None. There were no major differences between the diets, and success was completely dependent on what the individual could adhere to. In other words, practicality reigned king.

Similarly, one of the most frequent questions that’s asked by aspiring fitness enthusiasts is “Which is more important: diet or exercise?” With practicality in mind, we decided to take a look at the evidence.

A Primer on Calories

At a physiological level, weight loss and weight gain revolve around caloric consumption and expenditure*. Because of this, it’s important to understand the basics of calories. Put simply: we lose weight when we eat less calories than we expend. Conversely, we gain weight when we eat more calories than we expend. In order to lose one pound of fat, we must create a 3,500 calorie deficit, which can be achieved either through exercise or diet.

*As an aside, it’s worth noting that some argue that carbohydrates and insulin are the culprits behind weight loss and weight gain in what is called “the insulin hypothesis of obesity.” While controlling both carbohydrates and insulin may be important for some individuals, this hypothesis has been thoroughly debunked.

Let’s say that a 200 pound man wants to lose one pound in a week. Through exercise alone, he needs to run about 3.5 miles per day (or 24.5 miles total), assuming his diet stays the same. Through dieting alone, he needs to cut back 500 calories/day (the equivalent of two Starbucks Frappuccinos), given his exercise regime stays the same. Theoretically, the two should achieve the same results.

But in the world of fitness theory and reality are not the same thing, because theory does not account for adherence. We don’t live in a magical house that contains a gym, a Whole Foods, and a personal staff of nutritionists and trainers. Instead, we’re left about our own devices in everyday life. What happens then?

What the Research Says

Dr. John Briffa, who runs an excellent health blog, analyzed a study examining weight loss without dietary intervention here. He explains:

In this study, 320 post-menopausal women whose weight ranged from normal to obese were randomised to either an additional exercise or no additional exercise group (the control group). Those in the exercise group were instructed to take 45 minutes worth of moderate-vigorous aerobic exercise, 5 times a week for a year. Both groups (the additional exercise and the control group) were instructed not to change their diets.

At the end of the year, it was found that the exercise group, compared to the control group, lost an average of 2 kg (4.4 lbs) of fat. I’d say that quite a lot of us would be glad to drop a couple of kgs of fat. But now I’d also like to focus on what these women had to do to achieve this loss.

While the exercise group were instructed to exercise 5 times a week for 45 minutes, what they actually did was exercise for an average of 3.6 days each week. Total exercise time averaged 178.5 mins per week. We can multiply this by 52 to get the total number of minutes exercise over the course of the year, and divide this by 60 to convert it into hours. Doing this, we get a total of just under 155 hours. That’s about 77 hours of exercise for each kg of fat lost.

Most people would balk at the idea of exercising for 77 hours to lose 1 kg of fat. (Or equivalently 35 hours to lose 1 pound, for us American folk.)

But what about simultaneously exercising and accounting for dietary intake?

One study, published in the International Journal of Obesity and Related Metabolic Disorders, took trained subjects and had them track dietary intake along with energy expenditure. On paper, there was an overall caloric deficit created by the subjects. However, when researchers examined empirical changes, no weight was actually lost. As it turns out, subjects were simultaneously underestimating caloric intake and overestimating caloric expenditure.

Compare the studies above to the hilarious self-experiment by a nutritionist who went on the “Twinkie Diet” and subsequently lost 27 pound in 10 weeks. (Pro tip: Don’t try this at home.)

Why Exercise-Focused Regimens are Relatively Ineffective for Weight Loss

If you’re perplexed by the information above, don’t worry. There’s a simple explanation behind it, which we’ll break up into two parts

Reason 1. Calorie expenditure through exercise is relatively small in the grand scheme of things.

In order to see why exercise-focused weight loss programs might yield low efficacy, it’s important to understand the accounting behind our daily caloric expenditure.

We spend most of our calories every day just “staying alive.” This is known as our “resting metabolic rate.” The Katch-McArdle formula, which takes into account one’s body fat percentage, is the most accurate way to calculate this number, which is equivalent to:

9.81 x your amount of non-fat mass + 370 calories per day

Let’s say you are a 200 pound man who is at 30% body fat. You expend 1,743 calories per day just staying alive. (200 x (1-.30) * 9.81 + 370 calories)

He’ll expend about 10% on top of that by what’s known as the Thermic Effect of Food (TEF): the amount of calories that he spends digesting and absorbing his dietary intake.

Add another 10% on top of that through a metabolic process known as NEAT (Non Exercise Adaptive Thermogenesis). This is the amount of calories wasted through things such as fidgeting. Unfortunately, this can vary greatly from individual to individual.

This means that without so much as getting out of bed, our subject has already expended 2,100 calories.

Now, add another 10% for getting out of bed and going about his daily routine and he’s already burned 2,300 calories.

Adding exercise into the equation barely makes a dent in his overall caloric expenditure; most of the work is done before he puts on his running shoes. Now I am not saying that you shouldn’t exercise, but rather, it’s important to realize where a majority of your caloric expenditure is coming from. You wouldn’t take up a paper route in order to supplement a 100k/year salary, would you?

Reason 2. People are horrible estimators of calories in vs. calories out.

Take a look at another study, this one in the Journal of Sports Medicine and Physical Fitness, in which researchers asked the subjects to exercise, estimate their caloric expenditure, and then took them to a buffet afterwards. Subjects were asked to consume the amount of food that they believed they burned in calories. (Sidenote: Where can I sign up for one of these?)

The subjects ended up eating 2-3 times the amount of calories that they burned.

The takeaway from all of this information is that calorie expenditure doesn’t count for much, and human beings are generally terrible at estimating both expenditure and intake.

How to Effectively Incorporate Diet and Exercise

To make more sense of incorporating diet with exercise, I turned to my friend and obesity expert, Dr. Yoni Freedhoff. Yoni runs one of the largest obesity clinics in Canada and has helped countless individuals lose weight with a health and fitness approach. Yoni explains:

Most people I see struggle far more with their kitchens than with their gyms. They’ll readily find 30 minutes or more a day to hit the gym, go for walks, or simply up their daily activity by parking further away and taking the stairs more often, than they will for packing a lunch, prepping ingredients, cooking dinner, or keeping a food diary. I think in part it’s because that’s what the world believes — fuelled no doubt by shows like The Biggest Loser, and by the huge amount of money the food industry is throwing at the message of ‘balancing’ energy-in with energy-out, but also because we don’t get endorphin rushes from chopping vegetables or washing tupperware.

He then goes on to elaborate.

Most folks want to lose weight and to improve health and so both gyms and kitchens are required. That said, if weight’s a primary concern, I’d never ditch the kitchen in order to find the time to exercise. Instead take the total amount of time you think you’re willing to spend in the gym, and formally dedicate at least a third of that to the kitchen. As far as optimal amounts go, a person needs to like the life they’re living if they’re going to sustain it, so what’s right and optimal for one person will be too little or too much for another. The simplest litmus test question to ask is, “could I live like this forever,” and if the answer is “no,” you’ll need to change something up.

Given that Yoni has worked with a tremendous amount of successful patients, I asked for their commonalities.

The people who are most successful are those who embrace both consistency and imperfection. Think of starting out a weight management or healthy living program like you would a martial art. You’d never expect yourself to have a black belt from the get go. Instead, you’d start with really basic moves that you’d practice over and over and over again, you’d fall down a bunch, and doing so would be an expectation, and not a disappointment. And then slowly but surely you’d get better and better at it. Same thing is true when building any skill set, including healthful living, and just like you might be able to picture a jumping spinning hook kick in your mind’s eye when you start out at your dojo, that doesn’t mean you’ll be able to simply do one. So, too, with healthy living. Sure you might have a mind’s eye idea of what your healthy lifestyle should look like when you’re done, but getting there will be slow, plodding, and will include many falls.

He also shares some more great tips.

Never eat lunch out unless someone else is buying. Doing less exercise consistently is better than doing more intermittently – there are virtually no studies on diet or exercise that are long enough in duration to translate into lifelong recommendations or conclusions. Spending 2-3 minutes a day with a food diary is likely to have a bigger impact on your weight than 30 minutes a day in the gym.

Where to Go From Here

Ok, so I’ve given you a lot of information suggesting that exercise, as the sole means of creating weight loss, is relatively inefficient or even counterproductive. Here are the steps that you should take to best ensure your success.

  1. Determine how many calories you expend every single day. You can use ExRx’s calculator here. For best accuracy, calculate this by body fat percentage. If you don’t know your current body fat percentage you can use this helpful article by Leigh Peele.
  2. Reduce your calorie intake by 20% of your maintenance calories. Any time you decrease your caloric intake, it’s helpful to simultaneously increase your amount of protein in order to stay satiated. (Protein also has the higher Thermic Effect of Food out of any macronutrient, meaning your body needs to expend more energy to digest it in comparison to carbs or fats.)How much protein should you be eating on a caloric deficit? Nutritionist Alan Aragon recommends figuring out your target body weight and getting that amount in grams. For example, if you are a 200 pound woman who wants to get down to 120 pounds, consume at least 120g of protein per day.
  3. Once you are comfortable with counting calories, consider switching to counting macronutrients instead. Focusing on macronutrients, rather than calories calories, is a nice “hack” to disrupt the fact that people (myself included) are often translating exercise and eating into the same currency: calories. You can learn all about the basics of how to count macros here.

You’ll notice that the weight loss recommendation above makes no mention of exercise. But while you shouldn’t be factoring exercise into your caloric expenditure or intake, you should still be incorporating it as much as possiblepractical.

“Sure, weight is lost in the kitchen,” says Dr. Freedhoff. “But health is gained in the gyms.”


November 13, 2017
Sauna-min-1280x1920.jpg

by coco Ballantyne

We examine five claims about the benefits of weight lifting and aerobics to see which carry the most…weight

The Department of Health and Human Services (HHS) late this year released its new Physical Activity Guidelines for Americans, calling for adults between the ages of 18 and 64 to exercise moderately (such as brisk walking or water aerobics) for at least two hours and 30 minutes or vigorously (running, swimming, or  cycling 10 mph or faster) for at least an hour and 15 minutes weekly.

The longer, harder and more often you exercise, the greater the health benefits, including reducing the risk of diseases such as cancer and diabetes, according to the recommendations, which were based on a decade of scientific research.

Studies have shown that people who engage in the amount of exercise recommended by the feds live an average of three to seven years longer than couch potatoes, according to William Haskell, a medical professor at Stanford University who chaired the HHS advisory committee. But how exactly does exercise accomplish this? And what about claims by  naysayers that exercise not only isn’t healthy but may actually be bad for you? Is there any truth to them?

Good for the heart and blood vessels
In the past decade or so, various studies involving  thousands of participants have shown that workouts lower the risk of heart disease. “Exercise has a favorable effect on virtually all risk factors of cardiovascular disease,” says Jonathan Meyers, a health research scientist at the Palo Alto Veterans Affairs Health System in California. The reason, he says: when a person exercises, the heart muscle contracts forcefully and frequently, increasing blood flow through the arteries. This leads to subtle changes in the autonomic nervous system, which controls the contraction and relaxation of these vessels. This fine-tuning leads to a lower resting heart rate (fewer beats to pump blood through the body), lower blood pressure and a more variable heart rate, all factors that lower the risk of developing cardiovascular disease, he says.

Meyers says that exercise also limits inflammation associated with heart trouble, such as arteriosclerosis or hardening of the arteries around the heart, which may lead to heart attacks. Many recent studies have focused on C-reactive protein, a marker of inflammation. Meyers says that research showed that sedentary folks who embarked on three- to six-month exercise programs, on average, experienced a 30 percent dip in their C-reactive protein levels – about the same drop as someone given a statin (a cholesterol and inflammation-lowering drug). In other words, in many people, exercise might be as effective as an Rx in tamping down inflammation, one of the key risk factors for cardiovascular disease.

Exercise also boosts cardiovascular health by decreasing the amount of plasma triglycerides—fatty molecules in the blood that are associated with plaque build-up in the arteries— notes Haskell. What’s more, he adds, physical activity helps reduce the particle size of low-density lipoprotein (LDL) or so-called bad cholesterol in the blood, and increase amounts of high-density lipoprotein (HDL), aka good cholesterol, which translates to less artery clogging.

But exercise may not have the same effect on every person’s cardiovascular system, notes Arthur Leon, chief cardiologist at the University of Minnesota’s Heart Disease Prevention Clinic in Minneapolis. “On average, there is a response but there is great variability, and that variability runs in families,” he says. Take, for example, HDL cholesterol. Most broad studies show physical exercise leads to up to a 5 percent increase in HDL levels, but a closer examination shows that the percentages vary from zero to 25 percent, depending on the study subject, he says, noting that only about half of the population seem to experience HDL increases as a result of exercise.

Less cancer 
Several studies (including the ongoing federal National Health and Nutrition Examination Survey) following thousands subjects for several years, show that regular exercise lowers the risk for certain cancers, particularly breast and colon cancer, says Demetrius Albanes, a researcher at the National Cancer Institute in Bethesda, Md. Scientists have yet to pinpoint the mechanisms involved but have come up with several plausible explanations.

“Physical activity beneficially affects body weight,” says Albanes, noting that leaner people have lower circulating levels of insulin, a hormone produced by the pancreas that helps cells absorb glucose, their primary energy source. Obese and overweight people, are more likely to develop insulin resistance, a condition in which the cells no longer respond to the hormone and absorb glucose. When this happens, the pancreas produces greater amounts to compensate, flooding the bloodstream with insulin; high levels of insulin in the blood have been linked to [some types of] cancer. “Insulin is essentially a growth hormone,” Albanes says. “Insulin could create new tumors by increasing rates of cell division, or it could just make small tumors grow.”

Albanes says that exercise may also ward off cancer and other diseases because it appears to beef up the body’s immune system. Exercise may also help reduce levels of the female hormones estrogen and progesteronein the blood, potentially also lowering the risk of developing breast and uterine cancers linked to high levels of those hormones.

Despite the apparent link between physical exercise and lower odds of cancer, Albanes acknowledges that there could be other factors at work. “[Because] most of these studies are not controlled trials, it could be some other lifestyle factor [that helps explain the lower cancer risk], ” he says, noting that people who exercise may also eat healthier diets.

Builds strong bones
Robert Recker, an endocrinologist and current president of the National Osteoporosis Foundation in Washington, D.C., says research indicates that moderate exercise increases and maintains bone mass and reduces the risk of osteoporosis. “The most compelling evidence,” he says, “is that if you don’t do anything, your fracture risk is much greater.”

Like muscles, bones become stronger when forced to bear more weight than normal. “The skeleton is a smart structural organ and knows how much load [force] is being put on it,” Recker says. “Pick up a pail of water, and you’re loading your arm, your shoulder, your spine, your legs and your hips.” That means muscles are contracting, exerting forces on the bones supporting those body parts. This force stimulates the bone to maintain or even build new tissue. But scientists have yet to figure out why. “That’s a focus,” he says, “of incredibly aggressive research.”

Recker says that researchers speculate, however, that it has to do with exercise triggering osteocytes (the most mature bone cells) to instruct bone-building cells called osteoblasts to increase bone formation.

Wards off diabetes
According to Gerald Shulman, a cellular and molecular physiologist at Yale University School of Medicine in New Haven, Conn., exercising may prevent and even reverse type 2 diabetes.

Diabetes type 2 is a disease in which the body begins to ignore or fails to produce enough insulin (a condition called insulin resistance). If muscles and other tissues cannot absorb glucose from the blood, nerve and blood vessel damage ensues, paving the way for heart disease, stroke and infections.

“We’ve shown that in insulin-resistant individuals… build up of fat leads to biochemical reactions that interfere with the glucose-transport mechanism [leading cells to block the activity of insulin],” Shulman says. But physical activity helps reverse this process. He notes that when someone runs, cycles or does other vigorous exercise, muscle contractions ramp up production of adenosine monophosphate-activated protein kinase (AMPK), an enzyme that promotes the breakdown of the fats interfering with the cells’ glucose transporters.

“It is very likely that there are differences in the extent to which individuals respond to exercise, just as there are in responses to medications,” says Ronald Sigal, a clinical epidemiologist at the Ottawa Health Research Institute in Canada. Leon agrees, pointing to research demonstrating that exercise leads to varying decreases on visceral body fat(the fat surrounding organs), one of the key risk factors for developing type 2 diabetes.

Makes you smarter 

Researchers have long believed that exercise boosts smarts but there was not any hard scientific evidence until a few years ago. Now, says Fernando Gomez-Pinilla, a neurosurgery professor at the University of California, Los Angeles, it’s known that exercise increases levels of some molecules in the brain that are very important for cognition.

One such chemical is brain-derived neurotrophic factor (BDNF), a molecule that promotes the growth and survival of brain cells as well as communication between them. Studies in rats show that physical exercise boosts BDNF levels in the hippocampus, a brain structure critical for learning and memory formation, which in turn helps them remember how to navigate their way through underwater mazes. “The more exercise, the more changes in the brain; we found almost a linear relationship,” Gomez-Pinilla says. “If we block the BDNF gene, we block this capacity of exercise to help learning and memory.”

Numerous studies suggest that fitness enhances cognition in humans as well. A randomized clinical trial published recently in the Journal of the American Medical Association found that people 50 years and older with memory problems scored higher on cognitive tests after a six-month workout regimen. Those study participants assigned to exercise programs scored 20 percent higher than their sedentary peers at the end of the six months, and maintained a 10 percent edge one year after the trial ended.

But skeptics warn that not enough research has been done to confirm a link between exercise and human brain power. A recent review of studieson cognition in older adults (primarily those age 65 and older) by Dutch scientists published in the Clinical Journal of Sport Medicine concluded that “beneficial effects of various exercise programs on aspects of cognition have been observed in studies among subjects with and without cognitive decline. The majority of the studies, however, did not find any effect.”

Weight Loss 
The relationship between exercise and weight loss is complicated. Contrary to popular belief, working out at the gym every day will not necessarily lead to weight loss. “It is reasonable to assume that persons with relatively high daily energy expenditures would be less likely to gain weight over time, compared with those who have low energy expenditures,” write the authors of the American College of Sports Medicine (ACSM) and the American Heart Association’s (AHA) 2007 guidelines. “So far, data to support this hypothesis are not particularly compelling.”

“Increasing physical activity—if people control caloric intake—will lead to weight loss,” says William Haskell of Stanford University who helped craft the HHS, ACSM and AHA guidelines. But he cautions that exercise alone is unlikely to lead to the instant results most people want, leading them to become frustrated and give up. “[Suppose I do] 30 minutes of brisk walking five days per week,” says Haskell. “If you say walking a mile expends 100 calories, and if I walk at 3 miles per hour, I burn an extra 150 calories per day,” he says. “[Since one pound of fat is equivalent to about 3,600 calories], it could take three weeks to lose one pound. For most people, they are going to find this disappointing, [and] probably won’t stick with it.”

So for the average person, caloric intake—rather than calorie burning from exercise—appears to be the most important factor in weight loss. But even if calorie intake trumps exercise, this does not mean exercise does not play a key role in helping people stay trim.

“If you talk about energy balance [when calories consumed equal calories burned], definitely there is evidence that exercise contributes to energy balance,” says David Stensel, an exercise physiologist at the School of Sport & Exercise Sciences at Loughborough University in Leicestershire, England. A study published this month by Stensel’s team suggests that vigorous exercise suppresses the key hunger hormone, ghrelin, for up to 30 minutes after workouts and increases levels of the appetite-suppressing hormone peptide YY for as long as three hours after exercise.

Stensel also points to studies showing that exercising may encourage people to crave healthier fare, such as unrefined foods (like fiber-rich beans and veggies) rather than foods  loaded with refined sugar (such as cookies and cakes).

Some past researchers claimed that exercise would lead to weight gain in the long run because it ups one’s appetite. But Arthur Leon of  the University of Minnesota says that theory has been shot down over the past decade. Some research suggests that it might lead to greater caloric intake, Stensel notes, but that does not necessarily translate into extra pounds. The increased calories, he says, are not enough to offset the calories burned—or energy consumed—during exercising.

The bottom line: couch potatoes may applaud the exercise naysayers but the bulk of research suggests that workouts make us physically and perhaps mentally healthier.


November 13, 2017
Lockers-min-1280x1920.jpg

Exercise: 7 benefits of regular physical activity

You know exercise is good for you, but do you know how good? From boosting your mood to improving your sex life, find out how exercise can improve your life.

By Mayo Clinic Staff

Want to feel better, have more energy and even add years to your life? Just exercise.

The health benefits of regular exercise and physical activity are hard to ignore. Everyone benefits from exercise, regardless of age, sex or physical ability.

Need more convincing to get moving? Check out these seven ways exercise can lead to a happier, healthier you.

  1. Exercise controls weight

Exercise can help prevent excess weight gain or help maintain weight loss. When you engage in physical activity, you burn calories. The more intense the activity, the more calories you burn.

Regular trips to the gym are great, but don’t worry if you can’t find a large chunk of time to exercise every day. To reap the benefits of exercise, just get more active throughout your day — take the stairs instead of the elevator or rev up your household chores. Consistency is key.

  1. Exercise combats health conditions and diseases

Worried about heart disease? Hoping to prevent high blood pressure? No matter what your current weight, being active boosts high-density lipoprotein (HDL), or “good,” cholesterol and decreases unhealthy triglycerides. This one-two punch keeps your blood flowing smoothly, which decreases your risk of cardiovascular diseases.

Regular exercise helps prevent or manage a wide range of health problems and concerns, including stroke, metabolic syndrome, type 2 diabetes, depression, a number of types of cancer, arthritis and falls.

  1. Exercise improves mood

Need an emotional lift? Or need to blow off some steam after a stressful day? A gym session or brisk 30-minute walk can help. Physical activity stimulates various brain chemicals that may leave you feeling happier and more relaxed.

You may also feel better about your appearance and yourself when you exercise regularly, which can boost your confidence and improve your self-esteem.

  1. Exercise boosts energy

Winded by grocery shopping or household chores? Regular physical activity can improve your muscle strength and boost your endurance.

Exercise delivers oxygen and nutrients to your tissues and helps your cardiovascular system work more efficiently. And when your heart and lung health improve, you have more energy to tackle daily chores.

5. Exercise promotes better sleep

Struggling to snooze? Regular physical activity can help you fall asleep faster and deepen your sleep. Just don’t exercise too close to bedtime, or you may be too energized to hit the hay.

6. Exercise puts the spark back into your sex life

Do you feel too tired or too out of shape to enjoy physical intimacy? Regular physical activity can improve energy levels and physical appearance, which may boost your sex life.

But there’s even more to it than that. Regular physical activity may enhance arousal for women. And men who exercise regularly are less likely to have problems with erectile dysfunction than are men who don’t exercise.

7. Exercise can be fun … and social!

Exercise and physical activity can be enjoyable. It gives you a chance to unwind, enjoy the outdoors or simply engage in activities that make you happy. Physical activity can also help you connect with family or friends in a fun social setting.

So, take a dance class, hit the hiking trails or join a soccer team. Find a physical activity you enjoy, and just do it. Bored? Try something new, or do something with friends.

The bottom line on exercise

Exercise and physical activity are a great way to feel better, boost your health and have fun. Aim for at least 150 minutes per week of moderate-intensity exercise, or 75 minutes per week of vigorous exercise.

Try to engage in a combination of vigorous and moderate aerobic exercises, such as running, walking or swimming. Squeeze in strength training at least twice per week by lifting free weights, using weight machines or doing body weight exercises.

Space out your activities throughout the week. If you want to lose weight or meet specific fitness goals, you may need to ramp up your exercise efforts.

Remember to check with your doctor before starting a new exercise program, especially if you haven’t exercised for a long time, have chronic health problems, such as heart disease, diabetes or arthritis, or you have any concerns.


November 13, 2017
HHF-Pool-w_windows.jpg

Mandy Oaklander

Ever since high school, Dr. Mark Tarnopolsky has blurred the line between jock and nerd. After working out every morning and doing 200 push-ups, he runs three miles to his lab at McMaster University in Ontario. When he was younger, Tarnopolsky dreamed of becoming a gym teacher. But now, in his backup career as a genetic metabolic neurologist, he’s determined to prove that exercise can be used as medicine for even the sickest patients.

“People would always say to me, ‘Exercise? Come on. Scientifically, you can’t come up with a mechanism, so it’s a complete waste of time,'” Tarnopolsky says. “But as time goes on, paper after paper after paper shows that the most effective, potent way that we can improve quality of life and duration of life is exercise.”

Tarnopolsky has published some of those papers himself. In 2011, he and a team studied mice with a terrible genetic disease that caused them to age prematurely. Over the course of five months, half of the mice were sedentary. The other half were coaxed to run three times a week on a miniature treadmill. By the end of the study, the sedentary mice were barely hanging on. The fur that had yet to fall out had grown coarse and gray, muscles shriveled, hearts weakened, skin thinned–even the mice’s hearing got worse. “They were shivering in the corner, about to die,” Tarnopolsky says. But the group of mice that exercised, genetically compromised though they were, were nearly indistinguishable from healthy mice. Their coats were sleek and black, they ran around their cages, they could even reproduce. “We almost completely prevented the premature aging in the animals,” Tarnopolsky says.

That’s remarkable news, if you’re a mouse. And though there are obvious differences between rodents and humans, Tarnopolsky has seen something similar happen in his ill patients. “I’ve seen all the hype about gene therapy for people with genetic disease”–Tarnopolsky treats kids with severe genetic diseases like muscular dystrophy–“but it hasn’t delivered in the 25 years I’ve been doing this,” he says. “The most effective therapy available to my patients right now is exercise.”

Tarnopolsky now thinks he knows why. In studies where blood is drawn immediately after people exercised, researchers have found that many positive changes occur throughout the body during and right after a workout. “Going for a run is going to improve your skin health, your eye health, your gonadal health,” he says. “It’s unbelievable.” If there were a drug that could do for human health everything that exercise can, it would likely be the most valuable pharmaceutical ever developed.

The trouble is only 20% of Americans get the recommended 150 minutes of strength and cardiovascular physical activity per week, more than half of all baby boomers report doing no exercise whatsoever, and 80.2 million Americans over age 6 are entirely inactive.

The consequences of a sedentary life are as well documented as they are dire. People with low levels of physical activity are at higher risk for many different kinds of cancer, heart disease, Alzheimer’s disease and early death by any cause. That’s at the end of life. Long before that, inactivity can worsen arthritis symptoms, increase lower-back pain and lead to depression and anxiety–not to mention cause a sallow complexion.

Despite public-awareness campaigns, the health benefits of exercise have not been effectively communicated to the average American. Humans are notoriously bad at assessing the long-term benefits–and risks–of their lifestyle choices. And vague promises that exercise is “good for you” or even “good for the heart” aren’t powerful enough to motivate most people to do something they think of as a chore. Humans are, however, motivated by rewards. That is why experts like Tarnopolsky are so focused on proving that the scientific benefits of exercise–slower aging, better mood, less chronic pain, stronger vision, the list goes on–are real, measurable and almost immediate.

The U.S. National Institutes of Health (NIH) is on the bandwagon too. Next year the agency will launch a massive new study with the aim of documenting in unprecedented detail exactly what happens inside a body in motion. Its hope: to prove that exercise is medicine.

Before doctors adopted a single-minded focus on treating and curing diseases, their main goal was to keep people healthy. Even back in 400 B.C., doctors knew that diet and exercise were the best ways to do that. “Eating alone will not keep a man well,” Hippocrates famously wrote. “He must also take exercise.” For millennia, doctors were the vanguards of physical education–the original PE teachers. But in the early 1900s, with the rise of modern surgery and nascent pharmaceuticals, medicine shifted its focus from the prevention of disease to its treatment. Paradoxically, physicians de-emphasized exercise just as the modern Olympics swelled in popularity and colleges began building campus stadiums to accommodate America’s growing love of spectator sports. The authors of a paper published in a 1905 issue of the Journal of the American Medical Association mourned how many people were losing sight of the health benefits of exercise. “The men on the teams are the very ones whom Nature has endowed superabundantly with physical capacity, but on them the physical director bends most of his energies,” they wrote, “while the average student is left to get his physical development by yelling from the bleachers.”

Physical activity was no longer the medicine of the masses but the privilege of elite athletes. When scientists studied exercise, it was to figure out how athletes could improve their peak performance–not how mere mortals could improve their health day to day. This gap persists. At a time when boutique (read: expensive) fitness studios are more popular than ever, fewer people are getting the minimum recommended amount of exercise.

Worse, many U.S. schools have seen gym classes cut from the curriculum; nearly half of high school students don’t have weekly PE class, and only 15% of elementary schools require PE at least three days a week for the school year. The result: the majority of American kids and adolescents have so-called exercise-deficit disorder. Meanwhile, childhood-obesity rates have climbed every year since 1999. “You have whole generations that are soured on exercise,” says Jack Berryman, professor emeritus of medical history at the University of Washington School of Medicine.

Researchers like Tarnopolsky and Marcas Bamman, an exercise physiologist who also wants to be part of the NIH study, are hoping that their work will begin reversing those trends. Next year the NIH will launch its six-year, $170 million study with a group of about 3,000 sedentary people, ranging in age from children to the elderly. They will start an exercise program and then donate blood, fat and muscle before and after they exercise. Scientists will then examine samples for clues to how the body changes with physical activity. A control group that doesn’t exercise will also be tracked for comparison.

As part of the study, researchers will do the same experiment in animals to get tissue samples from places like the brain and the lungs that would be too dangerous to obtain from humans. “It’ll be a tremendously enormous data set,” says Maren Laughlin, program director for integrative metabolism at the NIH, who is also a lead on the new study. In the end, the researchers think they’ll be able to identify every single molecule in the body that’s tweaked or turned on by exercise.

This kind of study–its size, its rigor, its aims–is a first, and experts are hoping it will give doctors the evidence they need to start treating exercise like the miracle drug they’ve long thought it to be. “If you think of exercise as a true form of medicine, which it is, it’s not good enough to just look at a patient and say, ‘You need to do more exercise,'” says Bamman, director of the Center for Exercise Medicine at the University of Alabama at Birmingham. “That’s no better than handing someone a bottle of pills and saying, ‘Here, take a few,'” with no other explanation.

Bamman is betting that with this new data, exercise will one day be prescribed to patients. Instead of leaving the doctor’s office with nothing but a slip of paper with a drug name scrawled on it, patients may also get a detailed exercise plan tailored to make their medication work better. “We think that precision will go a long way in changing behavior,” Bamman says. “We’re at a really important time in the field.”

Think of all the different ways you can sweat and you might be surprised that each falls into one of just two categories. You’re doing aerobic exercise when your breathing speeds up, your blood flows faster and your heart pumps more of it, shooting oxygen out to the tissues in the rest of the body. It’s the most popular kind; about half of Americans meet the recommendations for aerobic physical activity. But only 20% also do the other type, strength training. The phrase may conjure grunting weight lifters and gym dumbbells slick with sweat, but to build muscle and strengthen bones, you really only need to use your body weight as resistance, says Anthony Hackney, an exercise physiologist at the University of North Carolina at Chapel Hill. That’s why things like yoga, tai chi and Pilates–not just pumping iron–are excellent forms of strength training. “People always get the image of the big, muscular guy,” Hackney says. “We try to think of muscle strength and power as a 65-year-old lady picking up a gallon of milk, pouring a glass and feeling comfortable.”

In addition to the heart, muscles, lungs and bones, scientists are finding that another major beneficiary of exercise might be the brain. Recent research links exercise to less depression, better memory and quicker learning. Studies also suggest that exercise is, as of now, the best way to prevent or delay the onset of Alzheimer’s, which is second only to cancer as the disease Americans fear most, according to surveys.

Scientists don’t know exactly why exercise changes the structure and function of the brain for the better, but it’s an area of active research. So far, they’ve found that exercise improves blood flow to the brain, feeding the growth of new blood vessels and even new brain cells, courtesy of the protein BDNF, short for brain-derived neurotrophic factor. BDNF triggers the growth of new neurons and helps repair and protect brain cells from degeneration. “I always tell people that exercise is regenerative medicine–restoring and repairing and basically fixing things that are broken,” Bamman says.

Repairs like this throughout the body may be the reason exercise has been shown to extend life span by as much as five years. A small new study suggests that moderate-intensity exercise may slow down the aging of cells. As humans get older and their cells divide over and over again, their telomeres–the protective caps on the end of chromosomes–get shorter. To see how exercise affects telomeres, researchers took a muscle biopsy and blood samples from 10 healthy people before and after a 45-minute ride on a stationary bicycle. They found that exercise increased levels of a molecule that protects telomeres, ultimately slowing how quickly they shorten over time. Exercise, then, appears to slow aging at the cellular level.

For all its merits, however, exercise is not an effective way to lose weight, research has shown. In a cruel twist, many people actually gain weight after they start exercising, whether from new muscle mass or a fired-up appetite. “Some people say exercise doesn’t do anything,” says researcher John Jakicic of the University of Pittsburgh. “Well, exercise does a lot. It just may not show up on the scale.”

One of the best pieces of news is that so much of what we already do counts as physical activity. “Mowing the grass, raking leaves, washing the car–all that’s exercise,” says Berryman, the exercise historian. “Physical activity includes all movement, not just throwing a ball through a basket.”

What’s more, emerging research suggests that it doesn’t take much movement to get the benefits. “We’ve been interested in the question of, How low can you go?” says Martin Gibala, an exercise physiologist at McMaster University. After all, if it were possible to reap all the health benefits of exercise in a tiny fraction of the time, who wouldn’t be compelled to give it a try?

Gibala wanted to test how efficient and effective a 10-minute workout could be, compared with the standard 50-minutes-at-a-time approach. The micro-workout he devised consists of three exhausting 20-second bouts of all-out, hard-as-you-can exercise, followed by brief recoveries. In a three-month study, he pitted the short workout against the standard one to see which was better.

To his amazement, the workouts resulted in identical improvements in heart function and blood-sugar control, even though one workout was five times longer than the other. “If you’re willing and able to push hard, you can get away with surprisingly little exercise,” Gibala says.

Not everyone can–or wants to–do this kind of excruciating workout, often referred to as high-intensity interval training, or HIIT. Many of us would gladly bounce around in Zumba class for an hour to avoid enduring even a minute of HIIT torture. But considering that a lack of time is the No. 1 reason people say they don’t exercise, a workout far shorter than what’s generally recommended could be a strong motivator. Gibala, for his part, is wondering if the workout can get even shorter. He’s even played around with the idea of a one-minute workout.

Not every type of exercise will work for every person, of course, but a growing body of research indicates that very vigorous exercise–like the interval workouts Gibala is studying–is, in fact, appropriate for people with different chronic conditions, from Type 2 diabetes to heart failure. That’s new thinking, because for decades, people with certain diseases and even pregnant women were advised not to exercise. Now scientists know that far more people can and should exercise. A recent analysis of more than 300 clinical trials discovered that for people recovering from a stroke, for instance, exercise was even more effective at helping them rehabilitate.

 

Dr. Robert Sallis, a family physician who runs a sports-medicine fellowship at Kaiser Permanente Fontana Medical Center in California, has prescribed exercise to his patients since the early 1990s in hopes of doling out less medication. “It really worked amazingly, particularly in my very sickest patients,” he says. “If I could get them to do it on a regular basis–even just walking, anything that got their heart rate up a bit–I would see dramatic improvements in their chronic disease, not to mention all of these other things like depression, anxiety, mood and energy levels.”

Older people, too, can benefit from strenuous exercise. Until now, all the recommendations for increasing bone density have included low-repetition, high-weight types of training, says Jinger Gottschall, associate professor of kinesiology at Penn State University. “But this just isn’t feasible for a lot of people. You can’t picture your grandma going in and doing that.” Luckily for Grandma, Gottschall’s team found that lifting lighter weights for more reps improves bone density in key parts of the body, making it a good alternative to heavy lifting.

It’s becoming evident that nearly everyone–young, old, pregnant, ill–benefits from exercise. And as scientists learn more about why that is, they’re hoping that those early 20th century missteps–the move away from our being bodies in motion–will be reversed. They’re also hoping that the messaging around exercise gets simpler. “People think now, because of the health-club and fitness movement, that in order to exercise you need to join a fancy club and wear fancy clothes,” says Berryman. In fact, some of the best exercise, research is showing, doesn’t require a gym membership at all (see right).

Back at McMaster University, Tarnopolsky and his team are almost finished doing autopsies on mice from their new study, and even though the scalpel-wielding scientists are blind to which groups the mice were in, they can tell with certainty which animals were allowed to exercise and which were sedentary. “You open up the sedentary mice and there’s fat all over the place,” he says. About half of those mice have tumors. “They just look god-awful.”

As for the mice who hit the wheel every day? “We haven’t found a single tumor,” he says. “I think if people saw, they’d be pretty motivated to exercise.”