The Science and Effects of Stress

  Cancer, cardiovascular disease, and diabetes are just a few of the most potent diseases plaguing humanity, but one of the most taxing disorders is so common that we barely even realize how much damage it is doing to us. Stress affects a vast majority of the population with research indicating that about 77 percent of the U.S. population regularly experiences physical symptoms from stress.¹ The number one stressor in the country: job pressure. And while you might think that the growth of technology and industry has helped, studies suggests otherwise. According to research by Carnegie Mellon University in Pittsburgh, stress has increased 24 percent for men and 18 percent for women from 1983 to 2009. In every specific demographic, stress increased anywhere from 10 to 30 percent.² Stress is more than gritted teeth and grumpiness. It presents some very real issues for your health and your relationships with others. Let’s take a closer look at stress in modern life and constructive ways to manage it.

The Science of Stress

When you think of stress, you probably imagine overbearing bosses, demanding clients, or piles upon piles of paperwork. In actuality, stress is your body’s response to any kind of demand, both good and bad. In its simplest terms, stress is your reaction to pressure. Far from being a negative attribute of humankind, stress is something of a necessity that has its roots in the basic survival mechanism of “fight or flight.” Say you’re one of your prehistoric ancestors, trying to make it on a vast African plain. You have to hunt and gather to survive, but you also have to keep on your toes for the lions, tigers, and various other predators that might enjoy you for lunch. When you encounter a lion during a hunt, you either have the option to hightail it out of there or stand your ground and hope you have the strength and skill to take that lion down. That’s where stress comes into play. The moment that you encounter a stressor—a hungry lion, in this case—your body’s system goes through several changes to ensure your survival.

• Your body releases all of its stored energies from fat and sugar to give you a quick boost of energy.
• Your breathing, heart rate, and blood pressure increase to get more oxygen to your blood and more blood to your muscles.
• Your body activates blood clotting mechanisms so that you don’t bleed out from cuts.
• Your muscles tense in preparation for instant action.
• All your senses get stronger so that you’re more aware of your surroundings. That means dilated eyes and sharper smell and hearing.

For all intents and purposes, there’s nothing inherently wrong with stress. In fact, a little stress is beneficial. This “good” stress, known as eustress, promotes the growth of new nerve cells in the brain, improving mental performance and keeping your mind alert.

When Stress Becomes Unhealthy

The problem is that eustress only refers to acute stress, or stress that is short and sudden, like a rollercoaster ride or when someone sneaks up behind you. Most modern workers deal with a series of acute stressors that stack up and turn into one large, long-lasting form of stress. This form of chronic stress doesn’t come with any of the same benefits of eustress and is downright destructive.

What Causes Stress?

The sources of stress are about as wide ranging as the symptoms of stress. Job pressures, money, and health are the top three causes in America, but even healthy people with job and financial security deal with stress. External stressors comprise outward situations and events that happen to you. These include:

• Major life changes, like moving across the country, getting married, or dealing with the death of a family member.
• Everyday things at work, like demanding supervisors, sudden deadlines, and immense workloads.
• Elements in your immediate environment, like the incessantly barking dog outside your window or the pollution in your city.

Internal stressors are self-induced, coming from within you, and include:

• Fears and phobias
• Doubt or a lack of control in your life
• Conflicts with your values and beliefs

And then there’s post-traumatic stress disorder, which is an extreme form of stress caused by an incredibly traumatic event. It is most often associated with soldiers who have been in combat but can also include those who have been victims or witnesses of violent crimes, experienced a natural disaster, or been in a serious car accident, for example. The fact is, stress can be caused by just about anything. You don’t need to justify your stress or feel shame about being stressed.

The Physical Effects of Stress

So you understand stress and the various factors that can contribute to it, but how does it affect your physical health? You may exhibit some basic symptoms, like headaches and low energy, but stress can lead to a whole lot of scary things.

• Brain shrinkage: Studies show that stress and depression turn on a genetic switch known as GATA1. This switch is responsible for regulating the processes of genes that eventually lead to the creation of connections in the brain. Without these connections, your brain actually loses mass.Another study showed that those who have been through extremely stressful situations—divorce or layoff—actually had smaller amounts of gray matter, particularly in the medial prefrontal cortex. This is the area responsible for regulating blood pressure, glucose levels, self-control, and certain emotions.
• Premature aging: Chronic stress has a harmful effect on DNA, namely on sections known as telomeres. A study found that those under frequent job stress had shorter telomeres, which can lead to DNA cell death and damage, both of which contribute to symptoms of aging.
• Increased risk of stroke: Those with high levels of stress and anxiety have been shown to have a 33 percent higher chance of having a stroke.³ Stress floods your body with the stress hormone cortisol and activates the hypothalamic-pituitary-adrenal axis, all of which work in conjunction to regulate various bodily functions. The prolonged activation of your HPA axis reportedly impairs your circulatory system, including the many veins and vessels in your brain, increasing your chance of stroke.
• Diminished heart health: Speaking of your cardiovascular system, your heart probably takes the biggest beating in moments of stress. The fight-or-flight response puts a lot of strain on your heart as it has to work harder to get blood where it needs to go while fighting against increased blood pressure in certain parts of your body. It’s no surprise then that chronic stress and the “stress gene”—the gene that makes some people more sensitive to stress—increase your risk of cardiovascular disease.The scientific community isn’t sure exactly why high cortisol levels equate to a higher heart attack risk, but many theorize that an increase in cortisol is also followed by an increase in an enzyme known as MMP-9. This enzyme makes plaque forming in your blood vessels more susceptible to bursting. Plaque that breaks off can form into clots that can eventually lead to heart attack.
• Diminished immune system: If you’re stressed during cold season, expect to be hit doubly hard by illness. Stress feeds your body’s inflammatory response. Inflammation is your body’s first line of defense against infections, but high levels of inflammation can only make you more vulnerable to diseases. Stress also prevents your immune system from responding to hormonal controls, making it weaker to act against viral infections.
• Digestive and gastrointestinal issues: Your digestive system is controlled by the enteric nervous system, which is directly connected to your central nervous system. Under stress, your central nervous system shuts down blood flow to the enteric nervous system, rerouting it to seemingly more important areas for fight or flight. This affects your digestive muscles and decreases the production of the fluid necessary for digestion.The fight-or-flight response also has other potential effects on your gut and digestive system. It can cause your esophagus to spasm. It can cause inflammation in your gastrointestinal lining. It can increase production of stomach acids. It can make you feel nauseated. However, contrary to common belief, stress won’t cause stomach ulcers, though it can make existing ulcers and other digestive diseases much worse.

Stress, Your Mind, and Your Emotions

Along with those physical symptoms, stress can manifest in your emotions and cognitive abilities. Stress and depression are very closely linked, leading to feelings of low self-esteem and a withdrawn personality. In that same vein, stress can make you moody and easy to anger. It’s not wrong to feel any of these emotions, but prolonged emotional distress can easily push away others and ruin relationships. Stress is so potent it can affect how you think, which makes sense considering your brain shrinks when stressed. Under repeated stress, the cells in your brain’s medial prefrontal cortex shrink. This area of the brain is responsible for performing attention-shifting tasks, so a shrunken prefrontal cortex means you’ll have a harder time adapting to situations that foster multiple stimuli. Do you need to make a difficult decision? You may want to wait until you’ve relaxed because stress can completely mess with your decision-making abilities. Studies show that stress affects how you see pros and cons of a decision, causing you to focus more on the pleasure and reward of your choice while ignoring the potential negative consequences of the outcome. And if you think you’re becoming forgetful in your age, you may actually just be stressed out. Cortisol prevents your brain from properly accessing existing memories or creating new ones. Prolonged stress damages the hippocampus—the part of the brain responsible for memory and learning. The hormone also interrupts neurotransmitters, which are the chemicals your brain cells used for communication. All of this spells difficulties for retrieving long-term memories under severe stress, which is why you might have trouble remembering your own name on a first date or the location of the emergency exit during a fire.

Stress and Behaviors

With all that said, it’s not surprising to imagine stress affecting your everyday behaviors, like your eating habits.

Overeating

Overeating is caused by two things. For one, because your body is in survival mode, it needs a constant supply of energy, usually quick energy from sugar, which is why you’re more likely to reach for the sweets. The big culprit of overeating is ghrelin, known as the hunger hormone. Stress causes ghrelin levels to rise. While studies have found that an increase in the hunger hormone can act as an antidepressant, ghrelin also causes a notable increase in food intake and weight gain.

Too Much Alcohol

And then there’s alcohol. Many people turn to that great equalizer that loosens tongues and inhibitions to relieve the stress they experience at the office, and to be fair, alcohol does relieve stress. Sort of. In limited doses, in specific situations, around specific people, alcohol can fight back some of the stress for certain people. Even then, alcohol isn’t a very good stress reliever. Although it reduces your body’s physiological response to stress, you would need to get drunk every time you were stressed, which isn’t really smart or recommended in the long run. Furthermore, your body doesn’t metabolize alcohol the same way it does a glass of juice or a sandwich. It takes a lot of energy to metabolize large doses of alcohol. You might feel relaxed but your body is actually under even more stress because of the extra metabolizing it has to do. It’s a vicious cycle. You drink because you’re stressed, but drinking only makes you more stressed. After a time, you may depend on alcohol to deal with your stress. There’s nothing wrong with drinking responsibly and having a good time, but using a drug—like alcohol—as your primary means of regulating your emotions is not healthy. To learn healthy ways to manage stress and improve your quality of life, please continue reading the second half of our two-part series.