The science of stress and your health

Sleeplessness, weight gain, indigestion, brain fog. Chances are you’ve experienced at least one of these symptoms recently, but you may be overlooking the real culprit: stress. 

Stress is so prevalent that we don’t tend to think much of it. But countless scientific studies have shown that the stress impact on health and well-being is serious – and common. In a 2021 survey, 74% of US adults said they’d experienced negative effects from stress in the past month, including headaches, fatigue and changes in sleeping habits. Plus, stress can have negative impacts on your mental health when it becomes chronic. 

But knowledge is the first step toward reducing the impact of stress on health. The more you understand what it is, what causes it and how it impacts your health, the more prepared you will be to manage stress – and create a life that is relaxing, instead of taxing.

What is stress?

Stress is both an emotional and physiological response that occurs when we feel threatened or overwhelmed. There are three different types of stress: acute, episodic and chronic. Each type presents differently and the stress impact on health also varies.

• Acute stress is an immediate reaction to an imminent threat, either perceived or real, such as a loud noise or crowded place. It’s your short-term fight–or–flight response: your heart races, your breathing quickens and your muscles may tense. Despite the fact that acute stress doesn’t last long, studies have still shown it can have negative health impacts. 
• Episodic stress is a less-severe form of acute stress that’s caused by recurring events in your life. If you sometimes have too much on your plate at work, feel like you’re always rushing to get the kids out the door or are planning a big event, you may feel episodic stress. It lasts longer than acute stress, but not as long as chronic stress. 
• Chronic stress is long term, lasting for weeks or months, and can vary in severity. You may feel constantly tense, agitated or angry, or you may feel sad. It’s even possible for the brain to adjust to chronic stress so that it begins to feel normal to you. But that doesn’t negate all of the negative impacts of stress on health.

What causes chronic stress?

While all types of stress impact health, chronic stress has the deepest effects. Yet there are some common life occurrences that cause chronic stress. Relationship and marriage difficulties, financial problems, trouble at work or poor work-life balance and mental or physical illness are all causes of stress that will affect most of us in our lifetimes. Teen stress is often caused by events at school or in the teen’s social circle.

Stress can also be caused by substance use and abuse, including caffeine, alcohol and tobacco. Loneliness or lack of a support system can contribute to stress. And, while certainty and uncertainty are both essential human needs, too much uncertainty can also lead to long-term chronic stress. Sometimes even positive changes in life, like getting a new job or buying a house, can cause stress due to the heightened pressure they bring with them.

How does stress affect the body?

Stress triggers a physiological response from the body. It begins to send out cortisol, a stress hormone.  Cortisol is useful in the fight-or-flight response, but when the body releases too much of it over time, negative stress impacts on health begin to appear.

Blood pressure:

Stress can raise your blood pressure by temporarily constricting your blood vessels and speeding up your heart rate. This can be harmful to your health if sustained over time.

Food cravings:

When you are under stress, you may find it harder to resist cravings for sugar or fat. You may also find yourself eating in an attempt to fulfill emotional needs — sometimes called stress eating or emotional eating.

Weight gain:

Research has shown that when your stress and cortisol levels are high, the body encourages the storage of fat, particularly in the lower abdomen area. This belly fat, also known as visceral fat, in turn increases inflammation and insulin resistance in the body.

Heart disease:

Coronary heart disease has been found to be significantly more common in individuals subjected to chronic stress. The incidence of heart attacks has also been shown to increase as a consequence of severe stress.

Insomnia:

Stress causes insomnia by making it difficult to fall asleep and to get a solid night’s rest. Stress also causes hyperarousal, which can upset the balance between sleep and wakefulness.

Tension headaches:

Stress causes your body to release chemicals like adrenaline and cortisol. These chemicals can cause vascular changes that leave you with a tension headache or migraine. Researchers have also found that stress-induced fluctuations in neurotransmitters – like serotonin and endorphins – also activate pain pathways in the brain, leading to headaches.

Memory:

Chronic stress has been shown to reduce spatial memory, the memory that helps you recall locations and relate objects. Researchers have also found a connection between an increase of cortisol and difficulty to form new memories.

Hair loss:

Acute stress has been shown to trigger three types of hair loss known as telogen effluvium, trichotillomania and alopecia areata.

Pregnancy:

Severe stress can increase the chances of premature labor. There have even been some studies that suggest very high levels of stress can affect the developing fetal brain. 

Digestion:

Stress can cause or worsen heartburn, stomach cramping and diarrhea. The common digestion issue known as IBS, irritable bowel syndrome, is also thought to be fueled by stress.

Brain function:

Brain-imaging studies have shown that chronic stress can reduce the amount of tissue in regions of the brain that regulate emotions and self-control.

Premature aging:

Chronic stress can shorten telomeres, the protective caps on the ends of cell chromosomes. As telomeres shorten, their cells age faster and die younger, contributing to premature aging and shorter human lifespans.

Colds:

Stress weakens the immune systems, making it difficult for individuals exposed to common cold viruses to fight off the germs successfully.

Sexual drive:

Research suggests that individuals who are stressed out tend to have a decreased sex drive and a less pleasurable experience during intercourse.

What about stress and mental health?

Stress can have negative impacts on your mental health when it becomes chronic. Studies suggest that when stress hormones are repeatedly released, it disrupts certain pathways in the brain and body and leads to an imbalance of other “happy hormones,” like serotonin and dopamine. Instead, your brain learns to live in a constant state of fear, always thinking disaster is around the corner. You’re tired, both physically and emotionally. This leads to the many ways that stress and mental health are interlinked – and the signs you may see:

Irritability

We all know someone who gets cranky when they’re tired or hungry. Chronic stress has a similar effect because it saps your energy and vitality. You snap at those around you. You lose patience quickly. You just can’t seem to control your emotions.

Anxiety

While stress is typically a response to an outside event, or stressor, anxiety is a more generalized feeling of worry or dread. The two are closely related, and chronic stress can lead to anxiety. In one study, 61% of adults who felt stressed also reported feeling anxious.

Depression

In the same study, 51% of adults reported feeling depressed in addition to stress. Other studies have found that stressful life events often precede depressive episodes, and that stress can cause inflammation, which may be a risk factor for depression.

Is stress always bad?

While much of the focus is on the negative stress impacts on health, some forms of stress can be useful. The body’s release of cortisol is meant to prime you to deal with potentially dangerous situations, so you can react quickly and decisively. Even some forms of episodic stress aren’t all bad. If you’re feeling the pressure of a big client presentation at work, you can use that pressure to help you make it the best it can be. If you feel scared before public speaking, you can use that fear as fuel to nail it.

If you find yourself constantly stressed at work or at home, that’s when it’s time to take a step back and ask yourself what the deeper meaning of this emotion is. It could be that you need better time management skills or that you’ve become addicted to the “high” of stress and need to schedule in some self-care time. Or it could truly be that the stress-causing event is out of your control – meaning that you need to focus on the only thing you can control: you. Practicing relaxation techniques and mastering your emotions is a good start.

The impact of stress on health can be serious, but you don’t have to feel stressed out all the time. By recognizing the physical and mental signs of stress, identifying their root cause and changing your habits accordingly, you can live a long, happy and healthy life.