Metabolic syndrome is rapidly becoming one of the biggest threats to the health and welfare of modern society. In simple terms, metabolic syndrome is a lifestyle disease directly linked to obesity. Clinical identification of the disorder is made when at least three of the following five characteristics are present: abdominal adiposity, hypertriglyceridemia, hypertension, dyslipidemia and insulin resistance.(1) The presence of any one of these conditions has been shown to increase the probability for the existence of the others.(2) The primary clinical outcome of metabolic syndrome is cardiovascular disease, but having the disorder also predisposes an individual to a variety of other maladies including polycystic ovary syndrome, fatty liver, cholesterol gallstones, asthma, sleep disturbances and even some forms of cancer.

    The incidence of metabolic syndrome in the western world has skyrocketed in the recent past. By current estimates, approximately 25% of U.S. adults have metabolic syndrome and an alarming 43% of those over 60 years of age are afflicted. The health-related impact of this epidemic cannot be overstated. Data from the Framingham Heart Study shows that metabolic syndrome alone is predictive of ≈25% of all new-onset cases of cardiovascular disease.(3) The Kuopio Ischaemic Heart Disease Risk Factor Study found that metabolic syndrome increased the risk of cardiovascular mortality by ~3-4 times after adjustment of other risk factors.(4) Moreover, metabolic syndrome is associated with a twofold increase in all-cause mortality,(4) resulting in a reduction in average life expectancy of five years.

    Considering that metabolic syndrome is directly associated with obesity, it stands to reason that losing body fat should be the primary target for intervention in those afflicted. Certainly proper diet is paramount to this end; reducing calories plays an essential role in creating a negative energy balance necessary for weight loss. Exercise, however, is arguably even more important here. Physical activity has been shown to serve as a key physiological regulator of thrifty genes to inhibit unhealthy adiposity(5) and exercise has been shown to cause a preferential reduction in belly fat.(6)

    It should be noted that physical activity has beneficial effects on combating metabolic syndrome above and beyond simply losing weight. Regimented exercise has been shown to positively influence cardiovascular risk factors including a lowering of triglyceride concentrations, decreasing concentrations of small LDL particles, increasing HDL-C concentrations, lowering resting blood pressure and reducing fasting blood glucose levels.(7) It should therefore come as no surprise that the prevalence of type II diabetes in highly active hunter-gatherer, rudimentary horticultural, simple agricultural and pastoral societies is but 1.1%(8) while an estimated 32.8% to 38.5% of female and male Americans, respectively, born in 2000 will contract the disease during their lifetime.(9) Considering that daily caloric expenditure in present westernized society has decreased by approximately 1200 calories compared with early 20th century hunter-gatherer societies,(10) it should be readily apparent just how important exercise is to metabolic health.

    Given the aforementioned facts, the question then becomes: Which type of exercise is best in the battle against metabolic syndrome? A definitive answer here is somewhat murky. When training frequency and duration are equated, both resistance training and aerobic have been shown to produce similar reductions in clinical risk factors for metabolic syndrome,(11) and there is evidence that combining the two types of exercise is more effective in combating the condition than either alone. Despite these findings, however, a good case can be made that resistance training has the greatest long-term impact on metabolic health.(12) Emerging research has found that muscle mass and strength are strong protective factors against metabolic syndrome; findings that are independent of aerobic fitness, insulin resistance, abdominal fat and other risk factors.(2) Possessing larger muscles enhances the uptake of glucose into muscle cells, perhaps accounting for the fact that resistance exercise has a more pronounced effect on improving glycemic control compared to endurance training in type II diabetics.(7) Moreover, basal metabolic rates following acute resistance training programs have been shown to be greater than after aerobic-type exercise programs, emphasizing the necessity of lifting weights in maintaining desirable body weight.(7) All things considered, resistance training confers unique benefits that makes it indispensible in the prevention and treatment of metabolic syndrome.

    The take-home message here should be clear: we need to become more active as a society or else risk the serious health-related consequences associated with metabolic syndrome. Simply getting up and moving around more would be a step in the right direction. For optimal metabolic wellness, however, more strenuous exercise is required. In particular, we must promote the importance of engaging in regimented resistance training that adheres to the principle of progressive overload. The good news is that health-promoting benefits can be achieved without much of a time commitment; just two or three non-consecutive sessions a week can have a huge impact in prevention and treatment. As fitness professionals, we must spread the word; the health of our nation depends on it.

    Brad Schoenfeld, MSc, CSCS, CSPS is regarded as one of America's leading fitness authorities. He is a lecturer in the exercise science department at CUNY Lehman College in the Bronx, NY and has over 30 peer-reviewed publications to his credit. As a trainer, he has worked with numerous high-level athletes and physique competitors, including many top pros. In 2011, he was named the NSCA Personal Trainer of the Year.

    1. Nakatani D, Sakata Y, Sato H, Mizuno H, Shimizu M, Suna S, et al. Clinical impact of metabolic syndrome and its additive effect with smoking on subsequent cardiac events after acute myocardial infarction. Am J Cardiol. 2007 Apr 1;99(7):885-9.

    2. Atlantis E, Martin SA, Haren MT, Taylor AW, Wittert GA, Members of the Florey Adelaide Male Ageing Study. Inverse associations between muscle mass, strength, and the metabolic syndrome. Metabolism. 2009 Jul;58(7):1013-22.

    3. Grundy SM, Brewer HB,Jr, Cleeman JI, Smith SC,Jr, Lenfant C, American Heart Association, et al. Definition of metabolic syndrome: Report of the national heart, lung, and blood Institute/American heart association conference on scientific issues related to definition. Circulation. 2004 Jan 27;109(3):433-8.

    4. Lakka HM, Laaksonen DE, Lakka TA, Niskanen LK, Kumpusalo E, Tuomilehto J, et al. The metabolic syndrome and total and cardiovascular disease mortality in middle-aged men. JAMA. 2002 Dec 4;288(21):2709-16.

    5. Sinha R, Dufour S, Petersen KF, LeBon V, Enoksson S, Ma YZ, et al. Assessment of skeletal muscle triglyceride content by (1)H nuclear magnetic resonance spectroscopy in lean and obese adolescents: Relationships to insulin sensitivity, total body fat, and central adiposity. Diabetes. 2002 Apr;51(4):1022-7.

    6. Hunter GR, Brock DW, Byrne NM, Chandler-Laney PC, Del Corral P, Gower BA. Exercise training prevents regain of visceral fat for 1 year following weight loss. Obesity (Silver Spring). 2010 Apr;18(4):690-5.

    7. Churilla JR, Magyari PM, Ford ES, Fitzhugh EC, Johnson TM. Muscular strengthening activity patterns and metabolic health risk among US adults. J Diabetes. 2012 Mar;4(1):77-84.

    8. Diamond J. The double puzzle of diabetes. Nature. 2003 Jun 5;423(6940):599-602.

    9. Narayan KM, Boyle JP, Thompson TJ, Sorensen SW, Williamson DF. Lifetime risk for diabetes mellitus in the united states. JAMA. 2003 Oct 8;290(14):1884-90.

    10. Cordain L, Gotshall RW, Eaton SB, Eaton SB,3rd. Physical activity, energy expenditure and fitness: An evolutionary perspective. Int J Sports Med. 1998 Jul;19(5):328-35.

    11. Potteiger JA, Claytor RP, Hulver MW, Hughes MR, Carper MJ, Richmond S, et al. Resistance exercise and aerobic exercise when paired with dietary energy restriction both reduce the clinical components of metabolic syndrome in previously physically inactive males. Eur J Appl Physiol. 2012 Jun;112(6):2035-44.

    12. Stensvold D, Tjonna AE, Skaug EA, Aspenes S, Stolen T, Wisloff U, et al. Strength training versus aerobic interval training to modify risk factors of metabolic syndrome. J Appl Physiol. 2010 Apr;108(4):804-10.