Cortisol is the fight-or-flight hormone you would love to live without, but simply cannot. Cortisol is excreted by the adrenal cortex, located at the top of the kidneys, and is responsible for a cascade of biological functions. Cortisol is responsible for energy regulation, mobilization, and storage. It is largely responsible for stubborn belly fat that accumulates during periods of prolonged stress. Exercise is often the prescription to ward off the long-term effects of this fat accumulation, but a simple exercise prescription is not as effective as once believed.
Exercise and Cortisol
Stress can wreak havoc on your body in many different ways. Excretion of cortisol is just one effect that affects your health. Many doctors and researchers agree that exercise is a great way to combat stress. Not only does it give you an outlet for your emotions, but it also inhibits the dangerous effects of cortisol on your cardiovascular system. However, C.H.E.K Institute researcher Dr. Mark Smith reported in 2008, not just any exercise routine will be effective. How you exercise plays a major role in cortisol excretion and thus in controlling its effects.
Running and Cortisol
Running is often the first "go-to" exercise when it comes to improving your health or seeking weight loss. It does not cost much and can be done almost anywhere. Indeed, running is good for your cardiovascular health. Studies published as far back as 1976, in the "Journal of Steroid Biochemistry," and as recently as 2000, in the "Journal of Clinical Endocrinology and Metabolism," show that running increases cortisol levels due to the amount of stress it places on the body and the necessity of mobilizing energy to ensure completion of the course. But before you hang up your running shoes, note that the intensity of your run can actually decrease the negative effects of cortisol on your metabolic processes and improve your body's fat-burning capabilities.
HIIT vs. Low- to Moderate-Intensity Exercise
In 2008, the C.H.E.K Institute published Smith's comparison of high-intensity interval training --- commonly abbreviated HIIT --- to low- to moderate-intensity cardiovascular training. During HIIT, you change the intensity of your workout by alternating periods of vigorous movement, like sprinting, with periods of slower movements, like jogging and running. Although these methodologies can be applied to a variety of cardiovascular activities, this study focused on running. Smith found that both methodologies increase cortisol levels, but that individuals who utilized the HIIT method while running also saw increases in hormones that inhibit fat accumulation and contribute to an overall decrease in body fat. Up to 24 hours post-exercise, HIIT runners continued to reap the benefits of increased energy expenditure and burning fat.
Battling Cortisol
You do not have to be a sprinter to inhibit cortisol's effects and achieve weight loss --- HIIT training can be applied to all levels of fitness. If you currently walk for exercise, you can add speed-walking intervals to your routine to achieve a similar effect. Over time, your walk may become a jog and your speed-walk may become a run. Success lies in challenging your body to push to the next level of intensity to increase energy expenditure. Always talk with your doctor before beginning a new exercise program. He can help you design a plan that suits your health and goals best.
References
- "Scandinavian Journal of Clinical Laboratory Investigations"; Plasma cortisol, androstenedione, testosterone and luteinizing hormone in running exercise of different intensities; K. Kuoppasalmi, et al.; September 1980
- "Journal of Steroid Biochemistry"; Effect of strenuous anaerobic running exercise on plasma growth hormone, cortisol, luteinizing hormone, testosterone, androstenedione, estrone and estradiol; K. Kuoppasalmi, et al.; October 1976
- C.H.E.K Institute; Sprint Interval Training --- It's a HIIT; Mark J. Smith, Ph.D.; March 2008
- "Journal of Clinical Endocrinology and Metabolism"; Effects of cortisol and growth hormone on lipolysis in human adipose tissue; M. Ottosson, et al.; February 2000
- "Pharmacology, Biochemistry, and Behavior"; Cortisol responses to mental stress, exercise, and meals following caffeine intake in men and women; W.R. Lovallo, et al.; March 2006
- "Endocrinology: An Integrated Approach"; Stephen Nussey and Saffron Whitehead; 2001
