Exercise as it relates to Disease/The Effects of Short Duration, High Intensity Exercise on Metabolic Syndrome

What is Metabolic Syndrome?
Metabolic Syndrome is a cluster of risk factors, a number of which can occur at the same time. These risk factors include, but are not limited to:
 * Central Obesity or BMI > 30;
 * Increased Triglycerides (>1.7nM);
 * Increased Fasting Plasma Glucose (>5.6nM);
 * Increased Blood Pressure (>130/85 mmHg); and
 * Increased Body Mass Index (>30).

Following the diagnosis of Metabolic Syndrome, treatment may initially involve low intensity exercise therapy as an intervention1, followed by Diet2 Pharmacotherapy and potentially Surgery.

What about the Prevalence of Metabolic Syndrome?
All of the risk factors comprising Metabolic Syndrome have existed for a long period of time, however it has only been recently that world organisations have started to create a succinct definition for what constitutes Metabolic Syndrome and develop prevalence data. The prevalence of individual risk factors varies amongst populations and therefore so to does Metabolic Syndrome. Physical activity levels, population age, diet and genetic structure all influence the prevalence of each risk factor and consequently Metabolic Syndrome. Irrespective of all of these underlying influences, the increased prevalence of Metabolic Disease worldwide has and will lead to negative health outcomes on a large personal, social and financial scale.3

What is Short Duration, High Intensity Exercise?
For general purposes, High Intensity Exercise can be defined as brief periods of high-intensity exercise intermixed with periods of recovery at a lower intensity, compared to a more conservative approach generally used for exercise prescription that would usually involve Continuous Low-Moderate Intensity Exercise. 4 This can be quantified as heart rates measuring >90% of recorded heart rate maximum.

What are the benefits of Short Duration, High Intensity Exercise in relation to Metabolic Syndrome?
In a world where time is a rare commodity, Short Duration, High Intensity Exercise provides a time effective way to reap the many benefits of exercise. The reasoning behind using High Intensity Exercise in both healthy and clinical populations, is that the segments of high intensity work promote greater adaptations via increased cellular stress and allow untrained individuals to conduct a higher rate of work than would otherwise be possible during Steady State or Low - Moderate Intensity Exercise. This is predominantly due to the short duration and corresponding recovery periods. 4 Some research indicates that Short Duration, High Intensity exercise may even be superior to Moderate Intensity Exercise5. Some benefits include, but are not limited to:
 * Improved Anthropometrics (<Waist circumference);
 * Decreased Fasting Plasma Glucose;
 * Improved Insulin sensitivity; and
 * Decreased Blood Pressure.

Recommendations: How can Short Duration, High Intensity Exercise be used as an Intervention?
With appropriate guidance and a structured training plan, High Intensity Exercise can be comprised of a variety training modes both individually and in combination. These include, but are not limited to:
 * Resistance Training;
 * Walking;
 * Running;
 * Swimming; and
 * Cycling.

Once selected, individually or in combination, exercises could be performed, as an example, in a simple format of 4 x 4 Minute intervals at 90% Heart Rate Maximum, followed by periods of 3 Minute recovery at 70% Heart Rate Max6. This presents an opportunity for an exercise session that is of shorter duration and broader variety, which may in turn create greater exercise compliance.

Precautions
Although current research has shown it is safe and effective to participate in Short Duration, High Intensity Exercise7, the following steps should be considered before participating:
 * Consult your General Practitioner for the most appropriate way to manage Metabolic Syndrome; and
 * Seek guidance from an appropriately qualified practitioner, such as an Exercise Physiologist.

Conclusion
Whilst it remains controversial which mode of exercise yields the most beneficial adaptations and is the most effective for reducing the impact of Metabolic Syndrome, recent research indicates that Short Duration, High Intensity Exercise reaps many of the same, if not more benefits than Continuous Low-Moderate Exercise.

Reference List
1.     Lakka, T. A. & Laaksonen, D. E. (2007). Physical Activity and Treatment in prevention of the Metabolic Syndrome. Applied Physiology, Nutrition and Metabolism. 32(1):76-88. Sited: http://www.ncbi.nlm.nih.gov/pubmed/17332786

2. 	Feldeisen, S. E. & Tucker K.L. (2007) Nutritional Strategies in the prevention and treatment of Metabolic Syndrome. Applied Physiology, Nutrition and Metabolism. 32(1):46-60. Sited: http://www.ncbi.nlm.nih.gov/pubmed/17332784

3.    Cameron, A. J. et al. (2004) The metabolic syndrome: prevalence in worldwide populations. Endocrinology and metabolism clinics of North America. 33(2):351-75. Sited: http://www.ncbi.nlm.nih.gov/pubmed/15158523

4. 	Kessler, H. S., Kisson, S. B. & Short, K. R. (2012). The Potential for High-Intensity Interval Training to Reduce Cardiometabolic Disease Risk. Sports Medecine (Auckland N.Z.) 1;42(6):489-509.. Sited: http://www.ncbi.nlm.nih.gov/pubmed/22587821

5.    Rognmo, O. et al. (2004). High intensity aerobic interval exercise is superior to moderate intensity exercise for increasing aerobic capacity in patients with coronary artery disease. European Journal of Cardiovascular Prevention and Rehabilitation. 11(3):216-22. Sited: http://www.ncbi.nlm.nih.gov/pubmed/15179103/

6.	Tjonna, A. E. et al. (2008) Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: a pilot study. Department of Circulation and Medical Imaging. 22;118(4):346-54. Sited: http://www.ncbi.nlm.nih.gov/pubmed/18606913

7.    Tjonna, A. E. et al. (2011) Time course of endothelial adaptation after acute and chronic exercise in patients with metabolic syndrome. Journal of Strength and Conditioning Research. 25(9):2552-8. Sited: http://www.ncbi.nlm.nih.gov/pubmed/21747296