Cortisol and abdominal fat

Lean women who are vulnerable to the effects of stress are more likely to have excess abdominal fat, and have higher levels of the stress hormone cortisol, a study conducted at Yale suggests [1].

While past studies have examined cortisol in overweight women, this study shows that lean women with abdominal fat have exaggerated responses to cortisol.

"We also found that women with greater abdominal fat had more negative moods and higher levels of life stress," says Elissa S. Epel, Ph.D., lead investigator on the study.

"Greater exposure to life stress or psychological vulnerability to stress may explain their enhanced cortisol reactivity. In turn, their cortisol exposure may have led them to accumulate greater abdominal fat."

Published in the journal Psychosomatic Medicine, the study looked at pre-menopausal, non-overweight women, and overweight women who stored fat either centrally — at the waist vs. peripherally — at the hips, and examined their stress responses over three consecutive days.

Cortisol is linked with an increase in central fat, which is found around the organs. People with diseases associated with extreme exposure to cortisol, such as severe recurrent depression and Cushing’s disease also have large amounts of visceral fat.

Not only is cortisol linked with the storage of abdominal fat, it's also been linked to all kinds of health problems, including diabetes, heart disease and depression. Cortisol may also weaken your immune system, leaving you more susceptible to colds and flu [3].

Cortisol has been shown to exert hyperphagic and antithermogenic effects [4]. In other words, it promotes overeating while blunting the normal rise in your metabolic rate that occurs after a meal.

This fat has been referred to as "toxic fat" since it's linked with the development of heart disease and type II diabetes.

After the first exposure to stress, women with greater abdominal fat felt more threatened by the study’s stressful tasks, performed more poorly on them, and secreted more cortisol. They also reported more life stress.

By the third exposure to stress, the lean women with abdominal fat still consistently secreted more cortisol in response to stressful lab tasks, compared to women with peripheral fat.

For lean women, central fat may indicate an underlying sensitivity to stress.

"It is possible that greater exposure to stressful conditions or psychological vulnerability to stress has led them to overreact to stressors in their daily lives, so they have had greater lifetime exposure to cortisol," Epel says. "Cortisol, in turn may have caused them to accumulate abdominal fat. Genetics, however, also play a role in shaping reactivity to stress, as well as body shape."

About The Author
Christian Finn holds a master's degree in exercise science, is a certified personal trainer and has been featured on BBC TV and radio, as well as in Men's Health, Men's Fitness, Muscle & Fitness, Fit Pro, Zest and other popular fitness magazines.

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References
1. Epel, E.S., McEwen, B., Seeman, T., Matthews, K., Castellazzo, G., Brownell, K.D., Bell, J., & Ickovics, J.R. (2000). Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat. Psychosomatic Medicine, 62, 623-632
2. Peeke PM, Chrousos GP. (1995). Hypercortisolism and obesity. Annals of the New York Academy of Sciences, 771, 665-676
3. Shinkai, S., Watanabe, S., Asai, H., & Shek, P.N. (1996). Cortisol response to exercise and post-exercise suppression of blood lymphocyte subset counts. International Journal of Sports Medicine, 17, 597-603
4. Chrousos, G.P. (2000). The role of stress and the hypothalamic-pituitary-adrenal axis in the pathogenesis of the metabolic syndrome: neuro-endocrine and target tissue-related causes. International Journal of Obesity and Related Metabolic Disorders, 24, S50-55
5. Berk, L.S., Tan, S.A., Fry, W.F., Napier, B.J., Lee, J.W., Hubbard, R.W., Lewis, J.E., & Eby, W.C. (1989). Neuroendocrine and stress hormone changes during mirthful laughter. American Journal of the Medical Sciences, 298, 390-396
6. Linkola, J., Fyhrquist, F., & Ylikahri, R. (1979). Renin, aldosterone and cortisol during ethanol intoxication and hangover. Acta Physiologica Scandinavica, 106, 75-82