Strength Training Trumps Endurance Training in Burning Fat and Promoting Human Health

Former Olympic speed skater Eric Heiden recently published the article ““Faster, Stronger, Better” via Tribune Media Services that you should definitely read. The five-time gold medalist, who now makes his living as an orthopedic surgeon, highlighted strength training as the key to weight loss and fat metabolism, and he cited a 2008 study in the journal Cell Metabolism.

The entire study is also worth checking out, but let’s take a look at some of the key excerpts. First, here’s a quick summary from the introduction:

While current pharmaceutical interventions are moderately effective in treating the clinical symptoms of metabolic syndrome, at this point only rigorous diet and lifestyle modifications (such as endurance exercise) are thought to be capable of significantly preventing harmful increases in fat mass that will ultimately shorten life span. Now, a new report by Izumiya et al. (2008) elegantly demonstrates that fast type IIb muscle fiber hypertrophy in response to Akt1 signaling blocks metabolic dysregulation and weight gain due to a high-fat/high-sugar diet, indicating that increasing fast muscle size via strength training may also be an important intervention for at-risk populations.

Metabolic syndrome is a relatively recent term which is used to describe a set of risk factors that, when present, place an individual at higher risk of developing diabetes, stroke, or coronary artery disease. The symptoms and features of metabolic syndrome are:

– Fasting hyperglycemia (diabetes mellitus type 2 or impaired fasting glucose, impaired glucose tolerance, or insulin resistance)
– High blood pressure
– Central obesity (also known as visceral, male-pattern or apple-shaped adiposity), overweight with fat deposits mainly around the waist
– Decreased HDL cholesterol
– Elevated triglycerides

The National Institutes of Health (NIH) estimates that approximately 47 million adults in the United States – or roughly 25 percent – have metabolic syndrome, and the numbers unfortunately continue to grow. Clearly, this is a major public health issue which needs to be addressed by utilizing the most effective means. And unfortunately, the conventional wisdom of “diet modification + cardio/endurance training” is simply not the most effective way to combat metabolic syndrome.

Now before all you dietitians and aerobics instructors train your flame throwers in my direction, let me be clear one one thing – diet modification and physical activity are both essential to combating metabolic syndrome. It is impossible to achieve optimal human health on a high-fat/high-sugar diet which has unfortunately become the mainstay of most Americans. And, yes, most us are way too sedentary when it comes to our activity patterns.

But the human body also needs to be physically stressed in ways that trigger positive gene expression. And while cardio/endurance training in moderation is helpful, it simply cannot match strength training when it comes to promoting positive gene expression.

Going back to the study:

Activation of Akt1 triggered a striking reduction of body mass due to decreased visceral fat mass and white adipocyte atrophy. These effects of enhanced Akt1 signaling on diet-induced obesity were directly related to muscle hypertrophy—blocking hypertrophy with rapamycin completely abolished the effects of transgene induction on body and fat mass.

In other words, fast muscle fiber development through strength training (muscle hypertrophy) led to increased fat/weight loss even when the test subjects were subjected to a high-fat/high-sucrose diet.

The analysis concludes accordingly:

Endurance training promotes slow muscle fiber adaptation, while fast muscle fibers are more responsive to resistance training paradigms. In humans, such training has been linked to reduced adiposity and improved insulin sensitivity and is now a recommended mode of exercise for individuals with type 2 diabetes ([Albright et al., 2000] and Schmitz et al., 2007 K.H. Schmitz, P.J. Hannan, S.D. Stovitz, C.J. Bryan, M. Warren and M.D. Jensen, Am. J. Clin. Nutr. 86 (2007), pp. 566–572. View Record in Scopus | Cited By in Scopus (8)[Schmitz et al., 2007]).

Bottom line – increasing skeletal muscle mass through appropriate strength training seems to be the key to triggering weight loss and alleviating the metabolic syndrome – which in turn helps prevent or fight diabetes, heart disease, stroke, hypertension, and even certain types of cancer.

So ditch that 90-minute spin class and go hit the weights instead…

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