You are probably thinking, "I know what stress is!" And you are right. But from a physiological standpoint, you experience a lot more stress than you think. Hans Selye, the godfather of stress, defined it as “the nonspecific response of the body to any demand made on it” (1). Anything that causes a disruption to your physiological balance is a stressor, according to this definition. It’s your stress response that matters most, not what causes your response. Stressors come in many shapes and forms, and while you may not always recognize these stressors, your body certainly does.
How Stress Works in the Body
The response begins in the brain with a perceived environmental or psychological stressor, activating the sympathetic nervous system: fight or flight (2). Your adrenal glands are triggered to release the stress hormones epinephrine, norepinephrine and cortisol. Epinephrine and norepinephrine cause physical arousal due to stress: increased heart rate, vasoconstriction, heightened alertness and sweating. Cortisol is released last and triggers the mobilization of stored glucose and fat cells to supply energy. It also shuts down digestion, immune and reproductive functioning (3, 4). Your brain can perceive and set off this stress response before you realize it’s happening. This is why people can catch a falling baby or avoid a speeding car even though they aren’t paying attention to the situation. If the brain perceives a continued threat, such as with chronic stress, the stress hormones' production will continue to keep the body on high alert. When the threat passes, the parasympathetic system (rest and digest) is activated to bring us back to homeostasis and allow us to recover from the stressful event (2). In everyday life, we are far more likely to have unpaid bills, be late to work or have an argument than an actual life threatening stressor. Your body goes through the same process for all stresses, regardless of the source.
Acute Versus Chronic Stress
We are biologically equipped to handle short but intense bouts of stress followed by periods of rest and recovery (5). Heavy emphasis on rest and recovery, folks! Modern life is filled with low grade stresses that take place all day long. This imbalance between chronic and acute stress leads to a number of health problems. Let’s imagine the analogy of car. When you drive a car around, it is designed to handle rapid acceleration occasionally. However, if you floor it every time you drive, eventually, the engine will break or burn out. Think of your body as the car and engine and the gas pedal as your stress response. If you are stressed all the time, eventually, the body will go into a state of dysfunction.
Sources of Stress: Nutrition and Sleep Deprivation
Managing blood sugar is one of the most important jobs in the body to ensure your survival. Both too high and too low of blood sugar cause dysfunction. When someone gets too low of blood sugar, it registers as a stressor, causing the release of cortisol (6). If your body cannot support the stress response, it will use cortisol to break down other tissues to meet those demands (7). Muscle, cartilage and bone are sacrificed in this response to provide amino acids so the body can make glucose to support stress (8). People can cause low glucose multiple ways that trigger the release of cortisol. These include not eating frequently enough and eating too many processed carbs and sugars (9, 10). Eating poor quality foods that cause inflammation is another stress for the body to manage. Inflammation and stress negatively impact digestion, metabolism and absorption of nutrients. Stress and inflammation are interrelated and amplify the damaging effects of one another. If you are eating unhealthy foods, you are creating both stress and inflammation (11, 12). Everything from waking up to a loud jolting alarm clock to using caffeine all day long and eating unhealthy foods all hit the same stress button.
The negative effects of sleep deprivation and stress intensify each other because sleep deprivation is a significant source of stress (13). What makes matters even worse is that sleep is the body’s most powerful anti-stress tool, allowing us to both mentally and physically rebuild and recover. When someone is sleep deprived, their body has a harder time regulating blood sugar and will be more likely to experience blood sugar swings and excessive appetite (14). With inadequate sleep, you will psychologically perceive events as more stressful and have a harder time regulating moods and emotions (15). When you create excessive stress in the body with your daily habits from nutrition to sleep, you can create a stress burden larger than your body can recover from. One area of your health that stress wreaks the most havoc is your hormones! Let’s take a closer look at what hormones do in the body, why they matter and what stress does to them.
How Hormones Run the Show
Hormones are chemical messengers that travel through the body and organize intricate processes related to growth, reproduction and metabolism (16). These hormones help the different body systems communicate with each other to make biological reactions take place. The reactions hormones control range from hunger to sleep, reproduction, metabolism and even your emotions and mood (16, 17, 18, 19). Hormones are tightly regulated in the body but can be disrupted by stressors such as nutrition, sleep, exercise and stress management.
The Stress Hormones
The hormones epinephrine, norepinephrine and cortisol are responsible for our physiological response to stress that you can feel (2). Cortisol regulates energy mobilization and shuts down the immune, digestive and reproductive systems to allocate more energy to managing stressors (20). When you have stress hormones flooding your body all day, you are putting your body in a catabolic state, encouraging the constant breakdown of tissues (21). Catabolism isn’t bad, but it needs to be balanced out with the anabolism or building. Chronic stress doesn’t allow for that balance to be struck between the two! When dealing with chronic stress and inadequate recovery, it results in higher blood pressure, depressed immune function, insulin resistance, diabetes risk and poor bone health (22, 24, 25). And to think we haven’t even discussed the negative side effects of how stress impacts your hormones yet...
How Chronic Stress is Ruining Your Hormones
The Pregnenolone Steal: Testosterone, Estrogen and DHEA
Your body views each stressful event as a potential life or death situation, which means it prioritizes the production of stress hormones over all other hormones. Pregnenolone is the master hormone and is converted to hormones such as DHEA, testosterone and estrogen. In times of chronic stress, the body preferentially converts pregnenolone into cortisol (26). Without these vital hormones, energy, cognition, libido, menstrual cycles, body composition and reproductive capacity will all suffer. Not to mention sleep problems and a slower metabolism are right around the corner (16, 27, 28).
Stress and Leptin/Ghrelin
Leptin and ghrelin are the two hormones in charge of regulating our energy balance along with hunger and satiety. Leptin signals satiety to the brain and turns off hunger, while ghrelin stimulates hunger and encourages eating (29). In the presence of chronic stress, leptin and ghrelin become dysfunctional. High levels of cortisol create leptin resistance, blocking the satiety signal in the brain. You will feel less satisfied from food (30). Ghrelin is brought to an abnormally high level when excessive cortisol is circulating, leading to an overstimulation of appetite (30). In the presence of chronic stress, you will feel the need to eat more food due to increased ghrelin. You will be less satisfied with that food because of blocked leptin signaling and make less healthy food choices (31). This is a powerful recipe for gaining body fat!
Stress and Insulin
Insulin is a storage and delivery hormone that transports glucose, amino acids and fat cells all around the body (16). Stressors shift your body to a catabolic state, where the main concern is breaking tissues and molecules down, not storage. As a result of chronic stressors, your cells become unresponsive to the storage hormone insulin’s signal and stop any storage or building (32). Having your cells unresponsive to insulin on a frequent basis will cause severe energy, metabolic and disease risk (33). Your body will use glucose far less efficiently and blood sugar and insulin levels will stay elevated for much longer, causing inflammation and putting you at a greater risk for type 2 diabetes (34, 35).
Stress and Thyroid Hormones
In the same way the adrenals run your stress response, the thyroid regulates your metabolism. The metabolism is responsible for your pulse, body temperature, energy, libido, reproductive capacity, digestion and energy production. The majority of thyroid hormones produced are the inactive form (T4). The conversion of inactive to active thyroid hormone (T3) is reduced by chronic stress (26). To make a bad situation worse, there are inflammatory byproducts of inflammation and stress named cytokines that further reduce the conversion of T4 to T3 (36). With lower levels of T3, the metabolism will become slower, and as a result, body temperature can lower, your pulse gets slower and energy throughout the day suffers. Digestion can slow down and libido will be decreased. It’s easy to see that stress comes in many different forms and can creep up in places we wouldn’t expect, like food choices or missing a few hours of sleep. These chronic stressors cause hormonal dysfunctions that put you at a greater risk for a number of diseases ranging from cardiovascular disease to type 2 diabetes. Recognizing stressors in your life is a huge part of winning the battle. You also need to know how to reduce stress in your life where it is chronic and persistent. In the next section, we will be discussing stress reduction techniques you can start using today that will improve your health and well being.
Tips For Reducing Stress
- Get seven to nine hours of sleep a night.
- Eat whole foods: vegetables, fruits, nuts, seeds, tubers, quality protein and healthy fats.
- Avoid highly processed carbohydrates and sugars: cookies, cupcakes, muffins, pastries, chips, pastas and energy and granola bars.
- Meditate: The free apps Headspace and Calm are both awesome!
- Write down three things you are grateful for in the morning.
- Change how you frame a situation. If you can change how you view a situation and see it in a different light, you take away its ability to stress you out.
- Engage in play: Play catch with a baseball or football or go play some basketball. Do something fun for yourself that you have no attachment to the outcome of.
- Schedule social events with those you love.
- Take a 20-minute walk. Get out into nature if possible or walk in a park. Nature has been shown to reduce stress!
- Practice deep breathing. Close your eyes and focus on the feeling of breath entering and leaving your body. Start with three minutes and work your way up to five to 10 minutes.
- Laugh more. Watch a funny movie, some stand-up comedy or a funny video on YouTube. Make it a daily habit to get a good belly laugh in at least once per day.