Stress is defined as a state of mental or emotional strain caused by adverse circumstances.

At one point or another, most people deal with feelings of stress. In fact, one study found that 33% of adults reported experiencing high levels of perceived stress (1).

The condition is associated with a long list of physical and mental symptoms.

This article will look at 11 common signs and symptoms of stress.

Acne is one of the most visible ways that stress often manifests itself.

When some people are feeling stressed out, they tend to touch their faces more often. This can spread bacteria and contribute to the development of acne.

Several studies have also confirmed that acne may be associated with higher levels of stress.

One study measured acne severity in 22 people before and during an exam. Increased levels of stress as a result of the exam were associated with greater acne severity (2).

Another study of 94 teenagers found that higher stress levels were associated with worse acne, especially in boys (3).

These studies show an association, but don’t account for other factors that may be involved. Further research is needed to look at the connection between acne and stress.

In addition to stress, other potential causes of acne include hormonal shifts, bacteria, excess oil production and blocked pores.

Summary Some studies have found that higher levels of stress are associated with increased acne severity.

Many studies have found that stress can contribute to headaches, a condition characterized by pain in the head or neck region.

One study of 267 people with chronic headaches found that a stressful event preceded the development of chronic headaches in about 45% of cases (4).

A larger study showed that increased stress intensity was associated with an increase in the number of headache days experienced per month (5).

Another study surveyed 150 military service members at a headache clinic, finding that 67% reported their headaches were triggered by stress, making it the second most common headache trigger (6).

Other common headache triggers include lack of sleep, alcohol consumption and dehydration.

Summary Stress is a common trigger for headaches. Many studies have found that increased stress levels are associated with increased headache frequency.

Aches and pains are a common complaint that can result from increased levels of stress.

One study made up of 37 teenagers with sickle cell disease found that higher levels of daily stress were associated with increases in same-day pain levels (7).

Other studies have shown that increased levels of the stress hormone cortisol may be associated with chronic pain.

For example, one study compared 16 people with chronic back pain to a control group. It found that those with chronic pain had higher levels of cortisol (8).

Another study showed that people with chronic pain had higher levels of cortisol in their hair, an indicator of prolonged stress (9).

Keep in mind that these studies show an association but don’t look at other factors that may be involved. Furthermore, it’s unclear if stress contributes to chronic pain or vice versa, or if there’s another factor that causes both.

Besides stress, there are many other factors that can contribute to chronic pain, including conditions such as aging, injuries, poor posture and nerve damage.

Summary Some studies have found that chronic pain may be associated with higher levels of stress as well as increased levels of cortisol.

If you feel like you’re constantly battling a case of the sniffles, stress may be to blame.

Stress may take a toll on your immune system and can cause increased susceptibility to infections.

In one study, 61 older adults were injected with the flu vaccine. Those with chronic stress were found to have a weakened immune response to the vaccine, indicating that stress may be associated with decreased immunity (10).

In another study, 235 adults were categorized into either a high- or low-stress group. Over a six-month period, those in the high-stress group experienced 70% more respiratory infections and had nearly 61% more days of symptoms than the low-stress group (11).

Similarly, one analysis looking at 27 studies showed that stress was linked to increased susceptibility of developing an upper respiratory infection (12).

More research on humans is needed to understand the complex connection between stress and immunity.

However, stress is just one piece of the puzzle when it comes to immune health. A weakened immune system can also be the result of a poor diet, physical inactivity and certain immunodeficiency disorders like leukemia and multiple myeloma.

Summary Stress may take a toll on your immune system. Studies show that higher stress levels are associated with increased susceptibility to infection.

Chronic fatigue and decreased energy levels can also be caused by prolonged stress.

For example, one study of 2,483 people found that fatigue was strongly associated with increased stress levels (13).

Stress may also disrupt sleep and cause insomnia, which can lead to low energy.

One small study found that higher levels of work-related stress were associated with increased sleepiness and restlessness at bedtime (14).

Another study of 2,316 participants showed that experiencing a higher number of stressful events was significantly associated with an increased risk of insomnia (15).

These studies show an association, but they don’t account for other factors that may have played a role. Further research is needed to determine if stress can directly cause decreased energy levels.

Other factors that may play a role in decreased energy levels include dehydration, low blood sugar, a poor diet or an underactive thyroid.

Summary Stress is associated with fatigue and disruptions in sleep, which may result in decreased energy levels.

Many people experience changes in their sex drives during stressful periods.

One small study evaluated the stress levels of 30 women and then measured their arousal while watching an erotic film. Those with high levels of chronic stress experienced less arousal compared to those with lower stress levels (16).

Another study made up of 103 women found that higher levels of stress were associated with lower levels of sexual activity and satisfaction (17).

Similarly, one study looked at 339 medical residents. It reported that high levels of stress negatively impacted sexual desire, arousal and satisfaction (18).

There are many other potential causes of changes in libido, including hormonal changes, fatigue and psychological causes.

Summary Some studies have found that higher levels of stress are associated with less sexual desire, arousal and satisfaction.

Digestive problems like diarrhea and constipation can also be caused by high levels of stress.

For example, one study looked at 2,699 children and found that exposure to stressful events was associated with an increased risk of constipation (19).

Stress may especially affect those with digestive disorders such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). These are characterized by stomach pain, bloating, diarrhea and constipation.

In one study, higher daily stress levels were associated with increased digestive distress in 181 women with IBS (20).

Additionally, one analysis of 18 studies that investigated the role of stress on inflammatory bowel disease noted that 72% of studies found an association between stress and digestive symptoms (21).

Although these studies show an association, more studies are needed to look at how stress may directly impact the digestive system.

Also, keep in mind that many other factors can cause digestive issues, such as diet, dehydration, physical activity levels, infection or certain medications.

Summary Some studies have found that stress may be associated with digestive issues like constipation and diarrhea, especially in those with digestive disorders.

Changes in appetite are common during times of stress.

When you feel stressed out, you may find yourself either with no appetite at all or ravenously raiding the refrigerator in the middle of the night.

One study of college students found that 81% reported that they experienced changes in appetite when they were stressed out. Of these, 62% had an increase in appetite, while 38% experienced a decrease (22).

In a study of 129 people, exposure to stress was associated with behaviors like eating without being hungry (23).

These changes in appetite may also cause fluctuations in weight during stressful periods. For example, a study of 1,355 people found that stress was associated with weight gain in overweight adults (24).

While these studies show an association between stress and changes in appetite or weight, more studies are needed to understand whether other factors are involved.

Other possible causes of appetite changes include the use of certain medications or drugs, hormonal shifts and psychological conditions.

Summary Studies show there may be an association between changes in appetite and stress levels. For some, higher levels of stress may also be associated with weight gain.

Some studies suggest that chronic stress may contribute to the development of depression.

One study of 816 women with major depression found that the onset of depression was significantly associated with both acute and chronic stress (25).

Another study found that high levels of stress were associated with higher levels of depressive symptoms in 240 adolescents (26).

In addition, a study of 38 people with non-chronic major depression found that stressful life events were significantly associated with depressive episodes (27).

Remember that these studies show an association, but don’t necessarily mean that stress causes depression. More research is needed on the role of stress in the development of depression.

Besides stress, other potential contributors to depression include family history, hormone levels, environmental factors and even certain medications.

Summary Some studies have found that high levels of stress may be associated with depression and depressive episodes.

A fast heartbeat and increased heart rate can also be symptoms of high stress levels.

One study measured heart rate reactivity in response to stressful and non-stressful events, finding that heart rate was significantly higher during stressful conditions (28).

Another study in 133 teenagers found that undergoing a stressful task caused an increase in heart rate (29).

In a similar study, exposing 87 students to a stressful task was found to increase heart rate and blood pressure. Interestingly enough, playing relaxing music during the task actually helped prevent these changes (30).

A rapid heartbeat may also be caused by high blood pressure, thyroid disease, certain heart conditions, and by drinking large amounts of caffeinated or alcoholic beverages.

Summary Several studies have shown that high stress levels can cause a fast heartbeat or heart rate. Stressful events or tasks may also increase heart rate.

Exposure to stress may also cause excess sweating.

One small study looked at 20 people with palmar hyperhidrosis, a condition characterized by excess sweating in the hands. The study assessed their rate of sweating throughout the day using a scale from 0–10.

Stress and exercise both significantly increased the rate of sweating by two to five points in those with palmar hyperhidrosis, as well as in the control group (31).

Another study found that exposure to stress resulted in high amounts of sweating and odor in 40 teenagers (32).

Excess sweating can also be caused by anxiety, heat exhaustion, thyroid conditions and the use of certain medications.

Summary Studies show that stress may cause increased sweating, for both people with sweating conditions like palmar hyperhidrosis and the general population.

Stress is something that most people will experience at one point or another.

It can take a toll on many aspects of health and has a wide range of symptoms, including reducing energy levels and triggering headaches or chronic pain.

Fortunately, there are many ways to help relieve stress, such as practicing mindfulness, exercising and doing yoga.