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  #1   ^
Old Wed, Feb-15-12, 03:04
Demi's Avatar
Demi Demi is offline
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Default How 1-Minute Intervals Can Improve Your Health

Quote:
From The NYTimes
February 15, 2012,

How 1-Minute Intervals Can Improve Your Health

By GRETCHEN REYNOLDS

While many of us wonder just how much exercise we really need in order to gain health and fitness, a group of scientists in Canada are turning that issue on its head and asking, how little exercise do we need?

The emerging and engaging answer appears to be, a lot less than most of us think — provided we’re willing to work a bit.

In proof of that idea, researchers at McMaster University in Hamilton, Ontario, recently gathered several groups of volunteers. One consisted of sedentary but generally healthy middle-aged men and women. Another was composed of middle-aged and older patients who’d been diagnosed with cardiovascular disease.

The researchers tested each volunteer’s maximum heart rate and peak power output on a stationary bicycle. In both groups, the peaks were not, frankly, very high; all of the volunteers were out of shape and, in the case of the cardiac patients, unwell. But they gamely agreed to undertake a newly devised program of cycling intervals.

Most of us have heard of intervals, or repeated, short, sharp bursts of strenuous activity, interspersed with rest periods. Almost all competitive athletes strategically employ a session or two of interval training every week to improve their speed and endurance.

But the Canadian researchers were not asking their volunteers to sprinkle a few interval sessions into exercise routines. Instead, the researchers wanted the groups to exercise exclusively with intervals.

For years, the American Heart Association and other organizations have recommended that people complete 30 minutes or more of continuous, moderate-intensity exercise, such as a brisk walk, five times a week, for overall good health.

But millions of Americans don’t engage in that much moderate exercise, if they complete any at all. Asked why, a majority of respondents, in survey after survey, say, “I don’t have time.”

Intervals, however, require little time. They are, by definition, short. But whether most people can tolerate intervals, and whether, in turn, intervals provide the same health and fitness benefits as longer, more moderate endurance exercise are issues that haven’t been much investigated.

Several years ago, the McMasters scientists did test a punishing workout, known as high-intensity interval training, or HIIT, that involved 30 seconds of all-out effort at 100 percent of a person’s maximum heart rate. After six weeks, these lacerating HIIT sessions produced similar physiological changes in the leg muscles of young men as multiple, hour-long sessions per week of steady cycling, even though the HIIT workouts involved about 90 percent less exercise time.

Recognizing, however, that few of us willingly can or will practice such straining all-out effort, the researchers also developed a gentler but still chronologically abbreviated form of HIIT. This modified routine involved one minute of strenuous effort, at about 90 percent of a person’s maximum heart rate (which most of us can estimate, very roughly, by subtracting our age from 220), followed by one minute of easy recovery. The effort and recovery are repeated 10 times, for a total of 20 minutes.

Despite the small time commitment of this modified HIIT program, after several weeks of practicing it, both the unfit volunteers and the cardiac patients showed significant improvements in their health and fitness.

The results, published in a recent review of HIIT-related research, were especially remarkable in the cardiac patients. They showed “significant improvements” in the functioning of their blood vessels and heart, said Maureen MacDonald, an associate professor of kinesiology at McMaster who is leading the ongoing experiment.

It might seem counterintuitive that strenuous exercise would be productive or even wise for cardiac patients. But so far none have experienced heart problems related to the workouts, Dr. MacDonald said. “It appears that the heart is insulated from the intensity” of the intervals, she said, “because the effort is so brief.”

Almost as surprising, the cardiac patients have embraced the routine. Although their ratings of perceived exertion, or sense of the discomfort of each individual interval, are high and probably accurate, averaging a 7 or higher on a 10-point scale, they report enjoying the entire sessions more than longer, continuous moderate exercise, Dr. MacDonald said.

“The hard work is short,” she points out, “so it’s tolerable.” Members of a separate, exercise control group at the rehab center, assigned to complete standard 30-minute moderate-intensity workout sessions, have been watching wistfully as the interval trainers leave the lab before them. “They want to switch groups,” she said.

The scientists have noted other benefits in earlier studies. In unfit but otherwise healthy middle-aged adults, two weeks of modified HIIT training prompted the creation of far more cellular proteins involved in energy production and oxygen. The training also improved the volunteers’ insulin sensitivity and blood sugar regulation, lowering their risk of developing Type 2 diabetes, according to a study published last fall in Medicine & Science in Sports & Exercise.

Since then, the scientists completed a small, follow-up experiment involving people with full-blown Type 2 diabetes. They found that even a single bout of the 1-minute hard, 1-minute easy HIIT training, repeated 10 times, improved blood sugar regulation throughout the following day, particularly after meals.

Of course, HIIT training is not ideal or necessary for everyone, said Martin Gibala, a professor of kinesiology at McMaster, who’s overseen the high-intensity studies. “If you have time” for regular 30-minute or longer endurance exercise training, “then by all means, keep it up,” he said. “There’s an impressive body of science showing” that such workouts “are very effective at improving health and fitness.”

But if time constraints keep you from lengthier exercise, he continues, consult your doctor for clearance, and then consider rapidly pedaling a stationary bicycle or sprinting uphill for one minute, aiming to raise your heart rate to about 90 percent of your maximum. Pedal or jog easily downhill for a minute and repeat nine times, perhaps twice a week. “It’s very potent exercise,” Dr. Gibala said. “And then, very quickly, it’s done.”
http://well.blogs.nytimes.com/2012/...ove-our-health/
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  #2   ^
Old Wed, Feb-15-12, 10:34
Sam Knox's Avatar
Sam Knox Sam Knox is offline
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Both shorter sprints and longer rest periods appear to be just as effective.

These guys sprinted for 30 seconds on a cycle ergometer then pedaled against no resistance for 4 minutes:

http://jp.physoc.org/content/575/3/901.full

Six of these intervals (~30 minutes total) turned out to be as effective as 2 hours of continuous cycling at 80% of maximum heart rate.

It's the sprints that do the trick. Rest periods should be long enough to allow you to perform the sprints successfully.
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  #3   ^
Old Fri, Mar-09-12, 12:20
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beernutz beernutz is offline
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I've been doing jumprope tabatas a couple of times a day, each time taking only 4 minutes, and I feel they've really helped my cardio. Right now I'm still doing basic two foot jumps and just going as fast as I can but you can introduce a lot of variability into how you jump to spice things up.
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  #4   ^
Old Fri, Mar-09-12, 12:27
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afwifey09 afwifey09 is offline
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Great article!
I started Tabata training too on 2/28 and I love it! That, combined with the 6 hours (minimum) per week of Zumba has me losing really quickly!
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  #5   ^
Old Fri, Mar-09-12, 12:38
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MizKitty MizKitty is offline
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Default

John Briffa blogged on this recently, and since reading it, I've been following his suggested HIIT routine with my exercise bike:
Cycling

• On a stationary bike, warm up for 2 minutes.

• Sprint at about 80–90 per cent intensity for 12–15 seconds.

• Cycle slowly for 45–48 seconds (so that the sprint plus rest makes a total of one minute).

• Repeat this sprint and rest for a total of 6–10 times.

• Cool down with gentle cycling for 2 minutes.

Seems a lot less intense than that suggested in the article above. (Maybe that's why I like it! lol)
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  #6   ^
Old Fri, Mar-09-12, 18:00
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joel381 joel381 is offline
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Quote:
Originally Posted by Sam Knox
Both shorter sprints and longer rest periods appear to be just as effective.

I saw you post on this before thought I would give it a try. Just starting out with 3 short (20-30sec) max efforts to get used to it. Thanks for the post.
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  #7   ^
Old Sat, Mar-10-12, 10:12
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Sam Knox Sam Knox is offline
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Joel,

If you want to look at some of the original research cited in the article (Gibala) you can find it here:

http://jp.physoc.org/content/575/3/901.full
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  #8   ^
Old Mon, Mar-12-12, 03:06
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Dalesbred Dalesbred is offline
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I recently introduced 10x30-second steep hill sprints into my weekly running regime and marmelised my 5 year old 10k PB last week (at 51) - surely some connection. And so much more invigorating than a steady plod!
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  #9   ^
Old Fri, Mar-16-12, 15:20
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MizKitty MizKitty is offline
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Default

And now for an opposing point of view...
http://douglassreport.com/2012/01/0...ot-to-exercise/

Quote:
Another reason not to exercise


If you’re looking to protect your heart, the last thing you want to do is punish it with super-intense workouts. The greater the strain, the greater the risk — that’s true for anyone, which is why even supposedly healthy people keel over and die after gym exercise.

And if your heart is already pumping under the strain of diabetes, pushing it to the limit with high-intensity exercise will only make matters worse — so naturally, that’s exactly what the mainstream wants you to do.

Researchers tortured eight diabetics with workouts that brought their hearts right to the brink — 90 percent of maximum heart rate — for a minute at a time during a 20-minute workout.

A minute of torture, a minute of rest… a minute of torture, a minute of rest — and so on. And after six of these workouts over two weeks, blood-sugar levels dropped by about 10 percent.

Whoop-do-doo.

Not only is that completely underwhelming, but if you keep up with these workouts, you can pretty much count the days until your next heart attack.

But you don’t have to put your heart on the line in the name of blood sugar control. In fact, you don’t have to spill even a drop of sweat to ace every blood sugar test, every time. All you need to do is swear off sugar and keep the rest of the carbs to a minimum.

For some more immediate help, try a cinnamon supplement (use a water-based extract, which minimizes the natural toxins present in cinnamon), and a synthetic form of thiamine called benfotiamine.


I trust Dr Douglas, love his blog, he's a lowcarb proponent.
I had just started doing a HIIT routine on an exercise bike, thinking I'm helping my insulin resistance and BG numbers, and now I don't know if I should continue.

Opinions on what he says?
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  #10   ^
Old Sat, Mar-17-12, 10:21
Sam Knox's Avatar
Sam Knox Sam Knox is offline
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Posts: 47
 
Plan: My own
Stats: 211/179/175 Male 6'3"
BF:
Progress: 89%
Location: Richland, Washington
Default

Quote:
Originally Posted by MizKitty
And now for an opposing point of view...
http://douglassreport.com/2012/01/0...ot-to-exercise/



I trust Dr Douglas, love his blog, he's a lowcarb proponent.
I had just started doing a HIIT routine on an exercise bike, thinking I'm helping my insulin resistance and BG numbers, and now I don't know if I should continue.

Opinions on what he says?



I feel like a mosquito at a nudist colony...I don't know where to start.

In general, Dr. Douglass overstates his case.

The HIIT protocol that he describes (1m sprint/1m rest x 10) isn't really representative. Typically, therapeutic HIIT sessions are 30s sprints between 4 minute rest periods repeated 4-6 times, a grand total of 3 minutes of exercise.

It's true that >90% MHR is the target, but that heart rate is achieved at the end of a sprint interval and lasts, literally, only a few seconds. Most of the people who do this kind of research think that the brevity of the sprints "buffers" the heart from stress.

Use of the term "mainstream" always raises a red flag for me. Advice isn't really mainstream or "alternative", there's either evidence that it has some benefit or there isn't.

I don't disagree that you can achieve normal blood sugar through diet alone, but you can add to that benefit with exercise, and that applies to blood pressure and heart-disease, as well. Anyway, life isn't just about blood sugar tests. Exercise will improve your overall quality of life, especially as you get older.

It's also true that there are risks associated with vigorous exercise, one of which is "cardiovascular events" but, like everything else, you have to balance the risks with the benefits. Your own doctor will have the best idea of whether or not the benefits outweigh the risks for you.

I've got a couple of blog posts about HIIT that I think are informative. You can look at them here: http://aworldlymonk.wordpress.com/

Finally, Dr. Douglass doesn't offer any evidence at all that what he says about exercise and heart attack risk is true. The evidence we do have suggests that, long- term, exercise reduces the risk of heart attack.

Sam
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