Interval training: Can it boost your calorie-burning power?

Interval training is a powerful tool for novice exercisers and accomplished athletes alike. Here's how it works.

By Mayo Clinic staff

Are you ready to shake up your workout routine? Do you wish you could burn more calories without spending more time at the gym? Consider aerobic interval training. Once the domain of elite athletes, interval training has become a powerful tool for the average exerciser, too.

What is interval training?

It's not as complicated as you might think. Interval training is simply alternating bursts of intense activity with intervals of lighter activity.

Take walking. If you're in good shape, you might incorporate short bursts of jogging into your regular brisk walks. If you're less fit, you might alternate leisurely walking with periods of faster walking. For example, if you're walking outdoors, you could walk faster between certain mailboxes, trees or other landmarks.

What can interval training do for me?

Whether you're a novice exerciser or you've been exercising for years, interval training can help you jazz up your workout routine. Consider the benefits:

• You'll burn more calories. The more vigorously you exercise, the more calories you'll burn — even if you increase intensity for just a few minutes at a time.
• You'll improve your aerobic capacity. As your cardiovascular fitness improves, you'll be able to exercise longer or with more intensity. Imagine finishing your 60-minute walk in 45 minutes — or the additional calories you'll burn by keeping up the pace for the full 60 minutes.
• You'll keep boredom at bay. Turning up your intensity in short intervals can add variety to your exercise routine.
• You don't need special equipment. You can simply modify your current routine.

How will my muscles respond to interval training?

During intense exercise, muscles produce waste products that can contribute to muscle soreness. Too many accumulated waste products can make exercise painful and exhausting. But by alternating bursts of intense exercise with easier intervals, you'll help reduce the buildup of waste products in your muscles. The result is more comfortable exercise.

Are the principles of interval training the same for everyone?

Yes — but you can take interval training to many levels. If you simply want to vary your exercise routine, you can determine the length and speed of each high-intensity interval based on how you feel that day. After warming up, you might increase the intensity for 30 seconds and then resume your normal pace. The next burst of more intense activity may last two to three minutes. How much you pick up the pace, how often and for how long is up to you.

If you're working toward a specific fitness goal, you may want to take a more scientific approach. A personal trainer or other expert can help you time the intensity and duration of your intervals — which may include movement patterns similar to those you'll use during your sport or activity — based on your target heart rate, the ability of your heart and lungs to deliver oxygen to your muscles (peak oxygen intake) and other factors. This type of interval training also adds variety to your workout, but it requires more discipline and concentration.

Does interval training have risks?

Interval training isn't appropriate for everyone. If you have a chronic health condition or haven't been exercising regularly, consult your doctor before trying any type of interval training.

Also keep the risk of overuse injury in mind. If you rush into a strenuous workout before your body is ready, you may hurt your muscles, tendons or bones. Instead, start slowly. Try just one or two higher intensity intervals during each workout at first. If you think you're overdoing it, slow down. As your stamina improves, challenge yourself to vary the pace. You may be surprised by the results.

Aerobic Exercise

Aerobic exercise gets the heart working to pump blood through the heart more quickly and with more force than normal. As blood is pumped faster, it must be oxygenated more quickly, which quickens respiration. Aerobic exercise strengthens the heart and boosts healthy cholestrol levels. Low impact aerobics include walking and swimming. Running, tennis and dance are high impact aerobics.

The Science behind Fat Loss Training

by Stephen Holt, Stemulite Fitness Pro

Alwyn Cosgrove’s Real World Fat Loss Manual points out that…

* A 2004 diet study that shows a simple change can increase dietary compliance and fat loss by 96% — (and it’s not “eat less”!)
* A 1998 study that showed that the addition of 45 minutes of hard aerobic training, 5 times a week for twelve weeks – had no effect on fat loss
* A study from 1994 showed an interval training method that actually reduced body fat (skinfold measurements) nine times more than traditional cardio training — despite taking less time, and actually burning fewer calories per session
* A 1999 study showed that the addition of a specific resistance training program increased fat loss by 35% over diet plus aerobic training
* That same study also showed that 3 aerobic sessions of up to 50 mins, for 12 weeks (36 sessions) only increased fat loss by one pound over dieting alone
* A 2002 study used an Afterburn-type approach to training – and showed an elevation of metabolism for 38 hours post workout.

Exercise Helps Treat Breast Cancer?

Combined Aerobic and Resistance Training in Breast Cancer Survivors: A Randomized, Controlled Pilot Trial

Herrero F, San Juan AF, Fleck SJ
Int J Sports Med
vol. 27, 573 - 580, 2006

Abstract

The purpose of this pilot study was to examine the effects of a combined cardiorespiratory and resistance exercise training program of short duration on the cardiorespiratory fitness, strength endurance, task specific functional muscle capacity, body composition and quality of life (QOL) in women breast cancer survivors. Sixteen subjects were randomly assigned to either a training (n = 8; age: 50 ± 5 yrs) or control non-exercising group (n = 8; age: 51 ± 10 yrs). The training group followed an 8-week exercise program consisting of 3 weekly sessions of 90-min duration, supervised by an experienced investigator and divided into resistance exercises and aerobic training. Before and after the intervention period, all of the subjects performed a cardiorespiratory test to measure peak oxygen uptake (O_2peak), a dynamic strength endurance test (maximum number of repetitions for chest and leg press exercise at 30–35% and 100–110% of body mass, respectively) and a sit-stand test. Quality of life was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC-C30) questionnaire. In response to training, QOL, O_2peak (mean 3.9 ml/kg/min; 95% CI, 0.93, 6.90) performance in leg press (17.9 kg; 95% CI, 12.8, 22.4) and sitstand test (–0.67 s; 95% CI, −0.52, −1.2) improved (p≤0.05). We observed no significant changes in the control group. Combined cardiorespiratory and resistance training, even of very brief duration, improves the QOL and the overall physical fitness of women breast cancer survivors.

An Article from Men's Health

Is Exercise a Waste of Time?

By David Zinczenko

Sometimes, when a news report seems to defy logic, it’s because someone hasn’t done their homework. And that’s what’s happened over at Time magazine with its latest cover story, “Why Exercise Won’t Make You Thin.” The article claims that working out is not only useless for weight loss, but can actually lead to weight gain.

This contention hinges mostly on a recent study done at Louisiana State University. Scientists there divided sedentary women into four groups: One group didn’t exercise, and three others performed different amounts of physical activity. All of the groups were told to stick to their typical diet.

The results: The women who exercised the most didn’t lose any more weight than those who didn’t exercise at all over six months. How can this be?

Well, first understand how much exercise these women were doing. The group that exercised the most burned around 1000 calories a week, or about 140 calories a day. The other two exercise groups burned around 700 and 350 calories a week, respectively.

This isn’t a tremendous amount of exercise—you might burn around 140 calories vacuuming your house—so no one would anticipate a tremendous amount of weight loss. Even so, the researchers calculated how many pounds they would expect each woman to lose, and their predictions were spot-on for the two groups that did lesser amounts of exercise. For these ladies, the exercise did indeed work.

(Make the most of your workout, by tapping into the 100 Greatest Fitness Tips of All Time.)

However, the other group of exercisers fell about two-and-a-half pounds short of their predicted weight loss. The Time story states: “Whether because exercise made them hungry or because they wanted to reward themselves (or both), most of the women who exercised ate more than they did before they started the experiment.”

Not so, according to the published data. The writer of the Time story either misread the results, or conveniently skipped over the parts that didn’t support his assertion. The study authors clearly state that the women in all four groups ate fewer calories on average.

(For an easy way to cut your calories—even when you’re in a hurry—discover the 14 Best Fast Food Meals Under 500 Calories.)

To be fair, the calorie-intake numbers probably aren’t accurate. The study’s lead author, Timothy Church, M.D., M.P.H., Ph.D., admits that since this data was attained from a survey—and not measured directly—it’s not very reliable. We really do suspect .

This further muddles the findings. And given that the non-exercisers lost weight, too, one could conclude this study proves that sitting on the couch causes weight loss. But Time magazine isn’t reporting that. At least not this week.

Instead, the Time author tries to support his notion that exercise doesn’t help you lose weight by pointing out that some women gained more than 10 pounds over the six-month study. “What the article fails to report is that other women lost even more weight than we expected,” says Dr. Church.

Bottom line: Our responses to diet and exercise are all highly individualized, explains Dr. Church. Sure, some people might compensate for their exercise by eating more, but according to Dr. Church, this isn’t the fault of exercise. More likely, he says, it’s because people don’t realize how easy it is to consume 1,000 calories at the drive-thru compared to burning just 250 calories on a treadmill. “If your weight is a concern for you, exercise is important. But it doesn’t give you license to eat what you want,” cautions Dr. Church. “You still need to pay close attention to what you’re putting in your mouth.”

Even so-called “healthy” food can have a surprising number of calories. Check out our list of the worst salads in America, including a 2,115-calorie salad from California Pizza Kitchen.

As for exercise making you hungrier, Dr. Church doesn’t think that’s the case. And overall, the research is mixed on the matter. But even if exercise does stoke your appetite, you still have the power of choice. Are you going to reach for an apple—or a big bowl of ice cream?

Dr. Church insists that we have much to learn on this topic, and wants you to know this: “When you look at people who lose weight and keep it off, what you find is that almost 100 percent of them not only watch what they eat, but are also regular exercisers.”

Want even more reasons why Time is wrong about exercise? Keep reading.

• Exercise can protect your muscle. A Penn State University study found that people who lifted weights along with a program of diet and aerobic exercise had the same weight loss as those who only dieted (or who dieted and performed aerobic exercise). The difference? The lifters lost 5 pounds more fat because almost none of their weight loss came from muscle. Read: Resistance training didn’t improve weight loss, but it did improve fat loss. And isn’t that what really matters?

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• Exercise may help you stick to your diet. University of Pittsburgh researchers studied 169 dieters for 2 years and found that the participants who didn’t follow a 3-hour-a-week training plan ate more than their allotted 1,500 calories per day. The reverse was also true—sneaking snacks sabotaged their workouts. “One healthy behavior without the other will not work—you need to diet and exercise to maintain long-term weight loss,” says lead study author John Jakicic, Ph.D. That’s because both actions can act as a reminder to stay on track.

• Exercise may target belly fat. While weight loss was similar among all four groups in the LSU study, only the groups that exercised saw their waist size decrease. The Time story downplays this finding, but isn’t it relevant? Think about it: This study actually shows that even a small amount of low-intensity exercise—performed in, say, just three 24-minute sessions a week—could help your jeans fit better. In other words, it makes you thinner. Doesn’t sound like a waste of time to me.

http://mhtoday.menshealth.com/2009/08/is-exercise-a-waste-of-time.html