Tag Archives: aerobic exercise

For Seniors on a Weight-Loss Diet, Resistance Training Beats Aerobics for Bone Preservation

according to an article at MedPageToday.

"One more rep then I'm outa here!"

“One more rep then I’m outa here!”

The two experimental groups had about 60 participants each, so it was a relatively small study. (In general, the larger the study, the more reliable the findings.) Most participants were white women; mean age was 69. The experimental intervention ran for five months. An excerpt:

In one trial, the participants were randomized to a structured resistance training program in which three sets of 10 repetitions of eight upper and lower body exercises were done 3 days each week at 70% of one repetition maximum for 5 weeks, with or without calorie restriction of 600 calories per day.
In the second study, participants were randomized to an aerobic program which was conducted for 30 minutes at 65% to 70% heart rate reserve 4 days per week, with or without calorie restriction of 600 calories per day.

The beneficial bone effect was seen at the hip but not the lumbar spine.

Thin old bones—i.e., osteoporotic ones—are prone to fractures. Maintaining or improving bone mineral density probably prevents age-related fractures. In a five-month small study like this, I wouldn’t expect the researchers to find any fracture rate reduction; that takes years. 

Most elders starting a weight-training program should work with a personal trainer.

Steve Parker, M.D.

Your Genes Determine Your Personal Response to Physical Training

Her response depends on genes, training program, nutrition, discipline, adequate sleep, adequate rest, etc.

Her response to depends on genes, training program, nutrition, discipline, adequate sleep, adequate rest, etc.

Here’s an excerpt from an interview with author David Epstein in Outside online. Epstein wrote The Sports Gene: Inside the Science Of Extraordinary Athletic Performance:

Interviewer: That’s one of the most fascinating and unexpected parts of the book, where you discuss the Heritage study’s findings on trainability. Explain its implications.

Epstein: That’s the most famous exercise-genetics study ever done. It’s the collaboration of five colleges in the U.S. and Canada. They took sedentary, two-generation families, which didn’t have a training history, and put them through stationary-bike exercise plans that were totally controlled. Families had to go into the lab and exercise over five months. The goal was to see how people would improve, and they were split into four different university centers to do the training and every center saw the exact same pattern. About 15% of people improved their aerobic capacity very little or not at all. And 15% improved 50% or more doing identical training. Families tended to stick together in the improvement curve, so about half of any person’s improvement was determined by their parents. I remember the editorial that ran in the journal of applied physiology “some people’s alphabet soup—meaning their DNA—didn’t spell ‘runner.’” One person training the exact same as another person can have completely different outcomes.

The exercise in this study was aerobic training. If I recall correctly, I’ve read similar reports regarding response to weight training, aka resistance training. Am I right?

Many folks don’t like to admit this genetic limitation, assuming it’s true. “Set your mind to it, work hard—10,000 hours—and you can do or be anything you want.” Have you ever been tortured by unrealistic expectations? The truth will set you free.

Read the rest.

Steve Parker, M.D.

Exercise Does and Doesn’t Help With Weight Loss

With regards to TV’s “The Biggest Loser” show:

The show’s 24-week regimen consists of approximately 4 hours of daily exercise, including 1 hour of intense resistance, 1 hour of intense aerobic activity, and 2 hours of moderate aerobic activity (for example, walking), along with a caloric  intake of at least 70% of estimated resting daily energy expenditure, explained Dr. [Robert] Huizenga, who is a former team physician to the L.A. Raiders football team.

exercise for weight loss and management, dumbbells

If you’re not familiar with resistance training, a personal trainer is an great idea

This is an excerpt from “The Biggest Loser Pushes Envelope on Diabetes,” in Internal Medicine News, vol. 45, No.11, page 17.

In a previous post about The Biggest Loser, I’d written that I didn’t know how much they exercised.

For purposes of discussion, let’s assume the documented major weight losses of Biggest Loser contestants is not simply due to caloric restriction.

Dr. Huizenga shared some of his experience at the recent annual meeting of the American Association of Clinical Endocrinologists.  In a study of 35 Biggest Loser participants, about half had prediabetes or type 2 diabetes.  Hemoglobin A1c, a measure of blood sugar control, fell significantly in this subset.  Three of the six with diabetes were able to stop metformin early on.  By week 29 of the study, average body mass index for the entire group had fallen from 46 to 29.

Yes, exercise helps with weight loss.  But most folks aren’t willing or able to exercise vigorously for four hours a day.  Physical activity is more important for maintenance of weight loss, when it demands much less time.

Steve Parker, M.D.

Momentary Muscular Failure and Resistance Training

I was planning to review here an article, Resistance Training to Momentary Muscular Failure Improves Cardiovascular Fitness in Humans: A review of acute physiological responses and chronic physiological adaptations.  It’s by James Steele, et al, in the Journal of Exercise Physiology (Vol. 15, No. 3, June  2012).

Exercise to momentary muscular failure may be safer on a machine

But it’s too technical for most of my readers. Heck, it’s too technical for me!  Too much cell biology and cell metabolism.  You’re dismissed now.  Maybe “American Idol” or “Honey Boo Boo” is on TV.

I’m just going to pull out a few pearls from the article that are important to me.  I ran across this in my quest for efficient exercise.  By efficient, I mean minimal time involved.

The authors question the widespread assumption that aerobic and endurance training are necessary for development of cardiovascular fitness.  Like Dr. Doug McGuff, they wonder if resistance training alone is adequate for the development of cardiovascular fitness.  Their paper is a review of the scientific literature.  The authors say the literature is hampered by an inappropriate definition and control of resistance training intensity.  The only accurate measure of intensity, in their view, is when the participant reaches maximal effort or momentary muscular failure.

The authors, by the way, define cardiovascular fitness in terms of maximum oxygen consumption, economy of movement, and lactate threshold.

“It would appear that the most important variable with regards to producing improvement in cardiovascular fitness via resistance training is intensity [i.e., to muscle failure].”

The key to improving cardiovascular fitness with resistance training is high-intensity.  These workouts are not what you’d call fun.

From a molecular viewpoint, “the adenosine monophosphate–activated protein kinase pathway (AMPK) is held as the key instigator of endurance adaptations in skeletal muscle.  Contrastingly, the mammalian target of rapamycin pathway (mTOR) induces a cascade of events leading to increased muscle protein synthesis (i.e.,[muscle] hypertrophy).”  Some studies suggest AMPK is an acute inhibitor of mTOR activation.  Others indicate that “resistance training to  failure should result in activation of AMPK through these processes, as well as the subsequent delayed activation of mTOR, which presents a molecular mechanism by which resistance training can produce improvement in cardiovascular fitness, strength, and hypertrophy.”

You’re not still with me, are you?

“… the acute metabolic and molecular responses to resistance training performed to failure appear not to differ from traditional endurance or aerobic training when intensity is appropriately controlled.”

Chronic resistance training to failure induces a reduction in type IIx muscle fiber phenotype and an increase in type I and IIa fibers.  (Click for Wikipedia article on skeletal muscle fiber types.)

“It is very likely that people who are either untrained or not involved in organized sporting competition, but you have the desire to improve their cardiovascular fitness may find value in resistance training performed to failure.  In fact, this review suggests that resistance training to failure can produce cardiovascular fitness effects while simultaneously producing improvements in strength, power, and other health and fitness variables. This would present an efficient investment of time as the person would not have to perform several independent training programs for differing aspects of fitness.”  [These statements may not apply to trained athletes.]

Before listing their 157 references, the authors note:

“It is beyond the scope of this review to suggest optimal means of employing resistance training (i.e., load, set volume, and/or frequency) in order to improve cardiovascular fitness since there are no published studies on this topic.”

In conclusion, if you’re going to do resistance training but not traditional aerobic/cardio exercise, you may not be missing out on any health benefits if you train with intensity.  And you’ll be done sooner.

Steve Parker, M.D.

PS: See Evidence-based resistance training recommendations by Fisher, Steele, et al.