Why Is Vigorous Exercise Gaining More Recognition For Long-Term Weight Loss?

In the last few years, there have been an increasing amount of reports and studies on the beneficial effects of vigorous exercise. over are increasingly more. What qualifies as vigorous exercise, and what will are the real benefits to your physical and mental long-term health?

While for most, vigorous exercise means 20 miles of running or hours and hours of physically taxing workouts, scientists are now discovering that relatively short duration, high-intensity interval training is the key to long-term weight loss, sometimes regardless of diet.

Some gymgoers are tortoises. They prefer to take their sweet time, leisurely pedaling or ambling along on a treadmill. Others are hares, impatiently racing through miles at high intensity.

The findings suggest that for at least one workout a week it pays to be both tortoise and hare — alternating short bursts of high-intensity exercise with easy-does-it recovery.

This alternating fast-slow technique, called interval training, is hardly new. For decades, serious athletes have used it to improve performance. But a workout with steep peaks and valleys can dramatically improve cardiovascular fitness and raise the body’s potential to burn fat.

Best of all, the benefits become evident in a matter of weeks.

Bursts of Exercise

Doing bursts of hard exercise not only improves cardiovascular fitness but also the body’s ability to burn fat, even during low- or moderate-intensity workouts, according to a study published this month, also in the Journal of Applied Physiology. Eight women in their early 20s cycled for 10 sets of four minutes of hard riding, followed by two minutes of rest. Over two weeks, they completed seven interval workouts.

After interval training, the amount of fat burned in an hour of continuous moderate cycling increased by 36 percent, said Jason L. Talanian, the lead author of the study and an exercise scientist at the University of Guelph in Ontario. Cardiovascular fitness — the ability of the heart and lungs to supply oxygen to working muscles — improved by 13 percent. Results were independent from any type of special dieting or food plans.

It didn’t matter how fit the subjects were before. Borderline sedentary subjects and the college athletes had similar increases in fitness and fat burning. “Even when interval training was added on top of other exercise they were doing, they still saw a significant improvement,” Mr. Talanian said.

Interval training isn’t for everyone. “Pushing your heart rate up very high with intensive interval training can put a strain on the cardiovascular system, provoking a heart attack or stroke in people at risk,” said Walter R. Thompson, professor of exercise science at Georgia State University in Atlanta.

Not for Everyone

For anyone with heart disease or high blood pressure — or who has joint problems such as arthritis or is older than 60 — experts say to consult a doctor before starting interval training.

Still, anyone in good health might consider doing interval training once or twice a week. Joggers can alternate walking and sprints. Swimmers can complete a couple of fast laps, then four more slowly.

There is no single accepted formula for the ratio between hard work and a moderate pace or resting. In fact, many coaches recommend varying the duration of activity and rest.

But some guidelines apply. The high-intensity phase should be long and strenuous enough that a person is out of breath — typically one to four minutes of exercise at 80 to 85 percent of their maximum heart rate. Recovery periods should not last long enough for their pulse to return to its resting rate.

What's Special About Interval Training

What is so special about interval training? One advantage is that it allows exercisers to spend more time doing high-intensity activity than they could in a single sustained effort. “The rest period in interval training gives the body time to remove some of the waste products of working muscles,” said Barry A. Franklin, the director of the cardiac rehabilitation and exercise laboratories at the William Beaumont Hospital in Royal Oak, Mich.

To go hard, the body must use new muscle fibers. Once these recent recruits are trained, they are available to burn fuel even during easy-does-it workouts. “Any form of exercise that recruits new muscle fibers is going to enhance the body’s ability to metabolize carbohydrates and fat,” Dr. Coyle said.

Interval training also stimulates change in mitochondria, where fuel is converted to energy, causing them to burn fat first — even during low- and moderate-intensity workouts, Mr. Talanian said.

Improved fat burning means endurance athletes can go further before tapping into carbohydrate stores. It is also welcome news to anyone trying to lose weight or avoid gaining it.

Unfortunately, many people aren’t active enough to keep muscles healthy. At the sedentary extreme, one result can be what Dr. Coyle calls “metabolic stalling” — carbohydrates in the form of blood glucose and fat particles in the form of triglycerides sit in the blood. That, he suspects, could be a contributing factor to metabolic syndrome, the combination of obesity, insulin resistance, high cholesterol and elevated triglycerides that increases the risk of heart disease and diabetes.

By recruiting new muscle fibers and increasing the body’s ability to use fuel, interval training could potentially lower the risk of metabolic syndrome.

Interval training does amount to hard work, but the sessions can be short. Best of all, a workout that combines tortoise and hare leaves little time for boredom.

An older study in 2005 that appeared in The Journal of Physiology, found that higher amounts of vigorous exercise cut deep belly fat and fat around the waist. . It took place at Duke University under the supervision of exercise physiologist Cris Slentz, Ph.D., and colleagues.

If Slentz had it her way, people would quit thinking "weight loss" and start thinking "health gain."

"Until we are able to prevent the weight that many dieters regain following short-term success, we should place a greater national emphasis towards prevention," says Slentz in a news release.

"It will be a challenge to change the message from 'exercise now to lose weight' to 'exercise now so in five years you won't be 20 pounds heavier,'" she continues.

'Hidden' Fat

If deep belly fat is hidden, why does it matter? The stakes may be too high for an out-of-sight, out-of-mind outlook.

Deep belly fat (technically called "visceral fat" or fat surrounding organs within the abdomen) has been linked to health problems including heart disease, type 2 diabetes, and metabolic syndrome -- a cluster of risk factors that greatly increase the chance of developing these diseases.

Visceral fat hasn't been proven to cause those conditions, but it seems to at least be a red flag of possible health risks, write Slentz and colleagues.

By the way, visceral fat isn't just for the millions of overweight or obese people. Thin people can also have visceral fat if they're not fit.

Mental Effects

In another study, research finds vigorous exercise equals better academics. The research was published in the Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.

For one academic year, the study tracked more than 200 sixth graders. For one semester half of the students took the general physical education class offered by the school, while the other half took part in a non-physical education course. Halfway through the school year they switched.

The researchers found that students taking the physical education course did no better or worse in their academic classes.

However, they also found that students who took part in more vigorous physical activities – such as organized sports like soccer or football, or non-organized after-school activities such as skateboarding – did approximately 10 percent better in core classes such as math, science, English and social studies.

“We have precious few studies that link activity or fitness to measurable academic outcomes,” said Jim Pivarnik, an MSU professor with appointments in kinesiology, epidemiology, and physical medicine and rehabilitation who is one of the study’s co-authors. “Considering all the factors that go into what determines students’ grades in school, a 10 percent increase by the most physically active kids is huge.”

It’s long been speculated that fitness and improved academic performance go hand in hand, said Dawn Podulka Coe, the study’s lead author who was a Michigan State University doctoral student when she led the project.

“Physical education and activity during the school day reduce boredom and help keep kids’ attention in the classroom,” said Coe, who is now an assistant professor in the Department of Movement Science at Grand Valley State University. “We were expecting to find that students enrolled in PE would have better grades because of the opportunity to be active during the school day. But enrollment in PE alone did not influence grades.

“The students who performed better academically in this study were the most active, meaning those who participated in a sport or other vigorous activity at least three times a week.”

The difference between vigorous activity and moderate activity is heart rate. Moderate activities, such as walking or raking leaves, don’t get the heart rate up or make the person breathe harder.

Vigorous activities, such as running or swimming for exercise, increase heart rate, causing the exerciser to breathe harder.

Burning Fat: Difference Between Walking And Running

Every kind of training, whether it's interval or otherwise has the potential to burn fat, it's how much fat is burned that makes the difference between one activity and the next.

Low-intensity exercise is not as effective as high-intensity exercise at burning calories. High-intensity exercise is not as effective (percentage wise) as low-intensity exercise at burning fat calories. Regardless, high-intensity exercise always wins the race at burning more total fat calories in the end.

Calories are an important consideration since you need to be in a daily calorie deficit to lose weight. Low-intensity walking typically burns a greater percentage of fat calories than running. For example, say you walk for 60 minutes and burn 300 total calories. The percentage of fat burned for energy usually averages about 70%. When you take 70% of 300 this means you've burned 210 fat calories. BUT jogging burns average 40% of calories from fat, so if you jogged the same duration (60 min) then you'll have burned likely over 600 calories. If 40% of those come from fat, that's 240 calories. So even though you're burning a lower percentage of fat calories when you jog, it is still a greater amount of fat calories and total calories in the end which helps maintain a daily calorie deficit and accordingly a greater chance at weight loss.

The problem with high-intensity exercise is that it's typically harder mentally and physically so it's difficult to keep up with it unless you program yourself and commit to a tough workout every week. Age and health are also factors. The best route: Alternate low-intensity and high-intensity to avoid burn out and make workouts more enjoyable and varied. This type of training gives you the highest probability of enjoyment and long-term success.