Human bodies have intricate ways of responding to stress. These stress responses helped our ancestors to survive and adapt to the sources of stress that they faced. Our inherited physical responses to stress are designed to get us away from danger or hunt another animal (fight or flight) as our ancestors did. Modern stressors do not require us to engage in physical activity. In fact, when people are experiencing stress, they are often sitting or lying down. Our bodies' stress responses were designed for a quick reaction that involved extreme physical engagement, so they do not serve us well in a lifestyle where stressors are often long-term and do not require us to run or fight.
While you are watching television shows about zombies or crimes, you are having a sustained stress response. Your body is responding by pumping cortisol, epinephrine and norepinephrine into your blood, as it would if you were in the situation on the screen. Cortisol is a stress hormone that pulls sugar out of cells and into the bloodstream. This makes the sugar available as fuel for muscle tissue to use in the kind of physical exertion that is required to run or fight. If a hunt or chase does not happen (if you stay sitting on the couch), the sugar is not used up by your muscles and continues to circulate through your bloodstream. If it is not used for physical activity, the sugar that was released in response to a stressful event tends to be deposited as belly fat.
Higher cortisol levels also make us less sensitive to leptin, the hormone that tells our brain that we are full. When people are insensitive to leptin, they cannot feel that they have eaten enough and they eat more than they would if they were getting the signal of fullness from leptin. This is why it is very easy to overeat and you may never feel full when you are in a stressful situation (and also why that bag of chips so easily disappears when you are watching a scary television show).
These are only a few of the ways that stress leads to weight gain and other health problems. I tell my patients that if they feel acutely stressed, either by life circumstances or by entertainment, they can prevent weight gain by going for a brisk walk or at least tightening and relaxing their leg muscles for 10 minutes. If people cannot miss the next episode of their favorite zombie show, I recommend that they do calisthenics like sit-ups, push-ups and jumping jacks during commercials or use an exercise bike or treadmill throughout the show so that while the suspense is building, they are burning the sugar that is released by cortisol instead of letting it get deposited as fat.
If you are trying to lose weight or if your blood sugar has been running high (pre-diabetes or type II diabetes), consider taking some time to list your biggest stressors and strategize about bringing physical activity into your day especially around times of acute stress at work, at home or when you are watching television. Exercise is the best medicine we have for managing stress and preventing the negative health effects of chronic stress.
Dr. Gwenn Rosenberg ND is a naturopathic doctor who practices with Natura Medica clinic in downtown Mystic. The family medicine practice utililizes therapeutic nutrition, homeopathic medicine, botanical medicine and lifestyle counseling as well as conventional therapies in disease treatment and prevention.