Fun fact: The biological mechanism that motivates us to take action can cause us tremendous harm when produced in excess. That mechanism is stress, and its side effects are not as mild as you might think. Understanding the negative impact that stress in overdrive has on our physical and mental health requires an examination of the chain reaction that produces it. When you detect a challenge or threat, your brain sets off an alarm via your body’s endocrine system. This is driven by what’s called the hypothalamic-pituitary-adrenal (HPA) axis.
What is the HPA axis?
Let’s start by defining some terms. Below is an explanation of the chain reaction that occurs in the HPA axis when under threat — and the components of the HPA axis that facilitate it.
- The hypothalamus is a bundle of nuclei that links the brain with the endocrine system. It’s responsible for relaying a distress signal to the pituitary gland when you perceive danger.
- The pituitary gland, which is located within the brain’s gray matter, produces a hormone when it receives a distress signal from the hypothalamus. That hormone triggers a stress response in the adrenal glands.
- The adrenal glands sit just above the kidneys, and are responsible for ramping up production of steroid hormones when the pituitary gland signals stress. Chief among these steroid hormones is cortisol.
- Cortisol sparks the mobilization of quick fuel — in the form of glucose and fatty acids — from the liver for the body to use.
When the body perceives stress for prolonged periods, this process will show signs of wear and tear, which can break down communication between the HPA access and the immune system. Over time, this breakdown leads to various health conditions, including depression, heart disease, and diabetes. But even along the way, prolonged levels of high stress can register in the body in perceptible ways. This head-to-toe look sheds light on some of both the near and long-term physical impacts — as well as ways to be proactive in counteracting them.
We’ve all experienced the type of pain in our head that has us rubbing our temples. One of its main triggers is stress. The tension headache is the most common. “It’s due to multiple chemical changes that occur in the brain,” says Alexander Mauskopf, MD, director of the New York Headache Center. “It’s not as simple as just an increase in cortisol. You have muscles around the scalp, in the temples, in the forehead, in the back of your head — all those muscles can tense up due to stress, and that hurts.” (Indeed, chronic tension in the muscles of the shoulder, head, and neck is associated with headaches.)
If you’re experiencing pain more than 15 days a month, then your tension headaches are considered to be chronic. Migraines, the other category of headache, can also be triggered by stress. “Close to 40 million Americans suffer from migraine headaches, except they don’t have severe migraines and some often don’t even know that they have them,” says Dr. Mauskopf.
Genetics is one of the variables at play. They can dictate who is more prone to reaching the tipping point, wherein stress triggers either type of headache. But the best practices for prevention measures are the same: Regular aerobic exercise, meditation, and magnesium supplementation. “Acute stress depletes magnesium pretty quickly, which leads to the constriction of blood vessels,” Mauskopf explains. The recommended dietary allowance (RDA) of magnesium is 400 to 420 milligrams for men and 310 to 320 milligrams for women.
2. Hair Loss
During the pandemic, health experts noted an increase in the number of people experiencing hair loss, even beyond the condition being a side effect of COVID-19 itself. “The type of hair loss which is stress-induced is called telogen effluvium. It is diffuse shedding that can come from any kind of physical or emotional stress and we’re definitely seeing more from factors surrounding the pandemic,” says Shilpi Khetarpal, MD, a board-certified dermatologist at the Cleveland Clinic in Ohio. “We don’t characterize this as everyday stress. It’s more like a major life event on a par with divorce or the death of a loved one that is triggering this.” Though the connection between shedding and physical stress (such as sickness or in the postpartum stage for women) are fairly straightforward, says Dr. Khetarpal, “we don’t know exactly how emotional stress causes hair loss.”
The Hair Cycle
In a healthy hair cycle, normally around 85 percent of hairs are in the growth phase. Five percent are resting, and around 10 percent are shedding, or in what is called the telogen phase. After a stressful period, up to 50 prcent of hairs can be pushed into the telogen phase prematurely. This is a shedding you’ll notice about eight to 10 weeks after the stressful event. That means fewer hairs are growing or resting, but many more are shedding. This results in the volume of your hair thinning.
“But the beauty of this is that it does resolve within six months and the hair does come back,” says Khetarpal. While working to minimize your stress level, there are a few science-backed ways she suggests to support new hair growth. For example, make sure you’re nutritionally covering your bases with a daily multivitamin and a well-balanced diet with adequate protein. (The RDA for protein is 0.8 grams per kilogram of body weight.) “Protein is one of the building blocks for our hair and our nails,” she notes. “And then those who are not pregnant or nursing can use topical minoxidil, a treatment which is sold over the counter, to speed up the process of hair growth.”
3. Heart Disease
When the heart gets the sign from stress hormones such as cortisol, it speeds up and intensifies its contractions. This is to increase circulation to the large muscles necessary to react. Meanwhile, blood vessels dilate to maximize the flow and blood pressure increases. When stress doesn’t let up and your body regularly experiences that increased heart rate and blood pressure throughout the day, it can elevate your risk for heart attack, hypertension, and stroke. “There are multiple associations between stress and heart disease and one is that the sympathetic nervous system response can cause a constriction of blood vessels, increase in heart rate and increase in blood pressure,” says Heather Moday, MD, author of The Immunotype Breakthrough: Your Personalized Plan to Balance Your Immune System, Optimize Health, and Build Lifelong Resilience.
With heart disease, plaque develops in blood vessels like arteries as an immune response to damage that must be repaired. “It’s like putting grout over a damaged brick and it gets larger and bumpier. And that attracts more things to get stuck to it,” says Dr. Moday. “If you have a very stressful event and the artery starts to constrict more, you might have a loosening of the plaque, and if it dislodges, it ends up blocking a blood vessel.”
Again here, regular exercise has a key protective effect. Not only can it reduce stress in the moment, but also condition the heart muscle. The American Heart Association (AHA) recommends at least 150 minutes of moderate-intensity or 75 minutes of vigorous intensity exercise weekly.
One of the hallmarks of chronic stress is that it leads to a state of perpetual, low-grade inflammation in the body. “Our body is always in the process of trying to repair, but it’s when we have a buildup of areas that are in need of repair that it becomes chronically inflamed,” explains Heather Moday, MD. This sort of inflammation is not visible, like a sprained ankle. However, it still takes a toll on our health in a number of ways. “Broadly, with autoimmune diseases, there’s some underlying inflammation — there’s a misguided immune response, and then we get tissue destruction rather than repair.”
Chronically high levels of cortisol can send the message to turn up our immune response indefinitely. “Inflammatory regulators in the body can be turned on when there’s chronic cortisol. And so those inflammatory regulators can increase the release of infection fighters called cytokines, which can put us in a more inflamed state,” says Dr. Moday.
Her list of best practices to keeping inflammation at bay includes steps that also help mitigate stress. Eating a healthy diet — especially avoiding trans fats and excess sugar and alcohol — is a good place to start. Additionally, getting the recommended seven to nine hours of sleep nightly is ideal.
5. Belly Fat
The connection between stress and weight gain can be a mix of factors linked to elevated cortisol, from the way the stress hormone spurs an increase in appetite, to its effect on how the body stores fat. “Cortisol stimulates the lipoprotein lipase [LPL], which is the gatekeeper for fat into cells. An excess of cortisol is going to favor the storage of fat,” says Eric Ravussin, MD, an obesity and diabetes expert at the Pennington Biomedical Research Center in Baton Rouge, Louisiana. “On average, it goes more toward the central fat deposition and especially the abdominal fat, but it varies from person to person.”
The Long Term Effects of Excess Belly Fat
If you picture your midsection, there are two kinds of body fat there. There’s the subcutaneous fat, which is just below the skin, and visceral fat, which surrounds the organs. “The real bad one is the visceral fat in the intra-abdominal cavity — this is around your heart, around your liver and also in your liver,” says Dr. Ravussin. “This fat is the most liable for your health and for your mental health.”
The American Heart Association released findings in 2021 that revealed people with too much abdominal fat were at increased risk for heart disease. This was regardless of whether their body mass index (BMI) was in a healthy range. A BMI for normal weight is between 18.5 and 25. Search for the BMI calculator at nhlbi.nih.gov to determine yours.
As the sensation of hunger itself can lead to an increased cortisol level, Ravussin notes that having regular, healthy meals is one way to stop the cycle of stress and craving. “Eat before you become hungry,” he says. And get proper sleep. “Short sleep duration is associated with obesity, and it’s been shown over and over.”
A version of this article appeared in our partner magazine How To Beat Stress: The Ultimate Guide To Feeling Happier.