Knowing stress is linked to cardiovascular disease and high blood pressure, physicians have been telling cardiac patients for decades to eat healthy, engage in physical activity, and manage stress. However, there are many other physical consequences of stress, such as muscle tension, skin disorders, respiratory disorders, gastrointestinal problems, and metabolic disorders. Metabolic syndrome and body fat distribution and their links to stress have been topics of recent research investigation. Can stress affect fat distribution and contribute to weight gain and body fat retention?
Our mind and our body are connected; thoughts and feelings affect how we physically feel. What happens to your body if you are nervous or anxious? Your palms may sweat, your blood pressure increases, your stomach may feel tied in knots, and you may even become nauseous. Similar effects occur when we are stressed. During acute stress, stressful thoughts release hormones from the brain, which in turn, releases a stress hormone called cortisol, among other stress hormones, from the adrenal glands. These hormones, in addition to the glucose released during the “fight or flight response,” gives us the energy necessary to face the “threat,” or stress. However with chronic stress, the extended hormone release suppresses the immune system, rendering us susceptible to infections, illnesses, certain cancers, and weakening bones. Chronic stress can also impair memory, worsen symptoms of depression, and alter metabolism, leading to non-insulin dependent diabetes mellitus (NIDDM) and obesity. In addition, stress can lead to a decrease in healthy behaviors, such as physical activity and engaging in a healthful diet, and an increase in unhealthy behaviors such as overeating, drug and alcohol abuse, and violence. The combination of these behaviors may also contribute to overweight and obesity.
Recent studies have examined the link between weight management and stress. In addition to the effects described above, the body also releases a chemical called neuropeptide Y (NPY) during stress. This chemical is linked with appetite, weight gain, and obesity. A team of researchers at Georgetown University Medical Center in Washington found that this neurotransmitter NPY can “unlock” certain receptors in the body's fat cells, thus promoting growth of the cells both in size and number (Kuo et al., 2007)..To explore this relationship, the research team fed groups of mice a high fat, high sugar diet, equivalent to human junk food, and exposed half of the mice to certain stressors in addition. Although all mice were on a high fat, high sugar diet, those that were stressed gained a significant amount of weight, about twice as much belly fat as those who were not stressed. Researchers concluded that NPY induces the growth of immature fat cells, coaxes mature fat cells to increase, and promotes blood vessels necessary to sustain fat tissue. The stressed out junk food eating mice gained the largest amount of fat, deposited around the abdomen, and developed high blood pressure, early diabetes mellitus, high cholesterol, and metabolic syndrome. In humans, this type of obesity would translate into the apple shape, or central type of obesity.
Other studies performed with mice have found that chronic social stress can have long-lasting effects on body fat distribution, mainly contributing to central (visceral) type obesity, leading to early metabolic disorders and obesity (Tashimiro, 2007). When controlling for genetic factors, such as a study performed with identical twins (Marnheim, et al., 2002), it was found that an increase in psychosocial stress was associated with various hormonal changes and visceral fat accumulation.
As obesity continues to be a health issue in the United States and around the globe, we need to add stress management techniques to physical activity and a healthful diet as a method for controlling overweight and obesity, reducing chronic disease, and contributing to an overall healthy lifestyle.
- Kuo, L., Kitlinska, J., Tilan, J., Lijun, L., Baker, S., Johnson, M., Lee, W., Burnett, M., Fricke, F. Kvetnansky, R.,,Herzog, H.,& Zukowsk, Z. (2007). Neuropeptide Y acts directly in the periphery on fat tissue and mediates stress-induced obesity and metabolic syndrome. Nature Medicine, 13(7), 803-811. doi:10.1038/nm1611.
- Marnheim, J., Kronholm, E., Aunila, S., Toikka, T., Mattlar, C.E., Koskenvuo, M., & Roennemaa, T. (2002). Visceral fat and psychosocial stress in identical twins discordant for obesity. Journal of Internal Medicine 251, 35-43. Retrieved from E-Journals database.
- Tamashiro, K. (2007). Social stress and recovery: implications for body weight and body composition. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 293(5), R1864-R1874. Retrieved from E-Journals database.
Anita Gust is an adjunct faculty member at the Kaplan University School of Health Sciences. She holds a master’s degree in exercise science from the University of North Dakota and is currently working on her doctorate in human development, with a specialization in wellness, at North Dakota State University.
Ms. Gust has an extensive teaching background in the areas of health, fitness, and sports medicine. In her current role, she enjoys interacting with her Kaplan University students from across the country and watching them grow. She loves to share her passion for learning with her students.