The amount of stress that people are exposed to is rising globally. Fast-paced lifestyles, profit-chasing business models, environments filled with stimulants for all the senses, as well as many other factors are all responsible for this. This article will review the importance of stress and the effects it can have on our health.

What is Stress?

Stress is the body’s response to different physical, environmental, and psychological factors. It is important to note that not all stress is bad and some amount of stress is needed for growth. For example, gravity is needed to keep our muscles strong, without the stress of gravity astronauts muscles start to waste away. On a long journey astronauts can lose as much as 30-40% of their muscle mass.

There are two types of stress; positive stress, which helps to build and negative stress, which breaks down.

Positive Stress: Positive physical stress are things like lifting weights, exercise, and gravity, which are needed to keep muscles and bones strong. Positive stress can also be emotional, like the stress of having a newborn baby or the stress of studying for an exam. Both may be challenging at the time, but allow you to progress as a person and learn new skills.

Negative Stress: Then there is negative stress, the stress that breaks down. This includes things like illness, injury, negative self-talk, conflict with others, toxins in the environment, lack of sleep, poor diets, and substance abuse.

Whether positive or negative stress, all stress has one thing in common, it always provokes a reaction from one or many systems within the human body. The most affected systems when it comes to stress are the nervous system and the HPA (hypothalamic pituitary adrenal axis).

While stress is a normal and necessary mechanism that enables the body to cope with challenging circumstances by altering metabolic, immunological, memory, psychological, and other functions; long-term exposure to stress can be extremely harmful.

Five major types of stress:

Stress comes in several different forms and can be long lasting or short term. Stress is triggered by a challenging life event like the loss of a loved one or a job or by a physical illness such as cancer or a car accident.

• Acute time-limited stress – a short-term response to a short-lasting stressor such as running a race
• Brief natural stress – a reaction to a normal, but stressful situation such as a tough meeting at work
• Stressful event sequence – a challenge that happens and continues to happen for a short time in the immediate future
• Chronic stress – long-lasting stress, potentially the most health-hazardous type of stress
• Distant stress – non-immediate stress such as an expected, stressful, event that will surely occur in the future. Such as finals week in school. 

Symptoms of Stress

Stress has an impact on our whole body. The following is a list of 25 physical and psychological symptoms commonly associated with stress:

· Headaches

· Muscle spasms

· Back or neck pain

· Frequent blushing

· Increased and frequent sweating

· Problems swallowing

· Heartburn

· Stomach pain

· Constipation

· Diarrhea

· Panic attacks

· Breathing difficulties

· Insomnia

· Increased appetite

· Nervous habits

· Difficulties concentrating

· Frustration

· Overreaction

· Fatigue

· Weight gain

· Alcohol and tobacco overuse

· Impulse buying

· Depression

· Anxiety

· Increased anger

The Effects of Stress

Chronic exposure to stress causes our overall health to deteriorate. Stress inhibits the normal communication inside the body, it affects the immune system, nervous system, musculoskeletal system, reproductive system, gastrointestinal tract, and various other tissues and organs.

The comprehensive effects of stress on the body are recognized as major factors in the development of many serious medical conditions, including cancer, heart disease, diabetes, depression, etc.

Effect on the Nervous System

The human nervous system is a complex one. The actions, reflexes, and processes that depend on its proper functioning are numerous. This is the main reason why the negative effects of stress on the nervous system are worrying.

To understand these effects better we first need to understand the nervous system itself. The human nervous system is made up of two major parts:

The Central Nervous System (CNS) includes the brain and spinal cord. Peripheral Nervous System (PNS) includes the nerves and is further divided into the somatic, autonomic, and enteric nervous systems.

The somatic nervous system is responsible for voluntary movement. The enteric system controls the gastrointestinal system. Lastly, the autonomic nervous system is responsible for arousal and relaxation. The autonomic system has two subdivisions; the sympathetic and parasympathetic nervous systems. The parasympathetic is activated when the body is relaxed, while the sympathetic is activated by stressors such as life-threatening and emergency situations.

When the nervous system detects environmental changes, such as stressors, it uses the nerve signals to alarm the endocrine system to respond. This response is known as stress. Although the brain has a major role in identifying the potential threat (stressor), the peripheral nervous system, especially the autonomic part, is most involved and affected by stress.

Fight or Flight Response

When the body is exposed to a serious threat, the sympathetic nervous system channels all the energy inside the body to fight this threat or escape from it. In other words, the body pumps the blood that was going to the stomach and bladder and sends it to vital organs; the brain, lungs, and muscles. In addition, the adrenal glands respond to the signals sent by the SNS and produce high quantities of cortisol and epinephrine (adrenalin).

Together this fight or flight response results in:

· Increased heart rate

· Increased respiration rate

· Dilatation of blood vessels in the limbs

· An increase in blood sugar levels

· Inhibition of the digestive process

All of this happens instantly and simultaneously. It is a normal response to short term stressors. Once this type of acute stress episode is over, the body returns to normal state quickly.

If the body is exposed to stress too often the stress can become chronic. Chronic stress causes the body to function in an abnormal state and exhausts the body by constantly activating the nervous and endocrine system. In the long run, this can cause various health issues such as hormone imbalances, digestive issues, sleep disturbance, fatigue, weight gain/loss, and breaking down of tissues.

Musculoskeletal System

Stress equals tension in the body and muscle tension is a good example of this. When the body is stressed the muscles become tensed and ready for action. This is a normal reflex that happens involuntarily and is the body’s way of providing additional protection from potential injuries during an attack or other threatening situation.

Muscle tension should disappear when the threat or stress is gone. However, when stress becomes a chronic state, muscle tension can become a serious issue that leads to pain and fatigue. Muscles actually need more energy to relax rather than to contract. When you feel tight muscles it’s because the muscles need time to recover and have enough energy so they can relax.

Conditions caused by long-term muscle tension are known as secondary musculoskeletal disorders. They are characterized by localized pain in different areas of the body, such as:

· Migraines

· Tension headaches

· Neck pain

· Shoulder pain

· Lower back pain

· Pain in the extremities

With chronic stress, these painful conditions usually also become chronic. The best way to treat them is through the controlled activity of the affected muscles, tendons, ligaments, and joints. Activity actually helps to relieve muscle tension and remove the effects of stress. On the other hand, lack of use of an affected body part leads to muscle atrophy and prolongs the effects of chronic stress.

Stress-relieving methods that can help to reduce muscle tension include:

· Meditation

· Yoga

· Progressive Muscle Relaxation (PMR)

· Walking

· Music therapy

· Weight-loss

· Singing

· Dancing

· Massage

· Breathing exercises

Respiratory System

Stress normally causes the breathing rate to increase. This is because under stress the body’s need to supply oxygen rich blood to different tissues, such as muscles is increased. Since the role of the respiratory system is to get oxygen into the blood, its an important part in stress response.

Breathing rate also increases during physical activity, so healthy individuals adapt to it rather easy. Increased breathing due to stress is more likely to affect the respiratory system of those who are already suffering from respiratory conditions, such as:

· Asthma

· Emphysema

· Chronic bronchitis

· COPD (Chronic Obstructive Pulmonary Disease)

In people with asthma, acute psychological stressors can trigger sudden attacks. Likewise, those who suffer from COPD can experience severe shortness of breath. A stressor can emotional like hearing distressing news or physical like running from a bear. 

Hyperventilation or rapid breathing is another common respiratory system issue that is often a result of stress. Hyperventilation is not so much connected with physical conditions, such as asthma or COPD. It is more likely to happen as a psychological reaction, especially in people prone to panic attacks.

As with other stress-related problems, respiratory system issues are best managed by relaxation therapy. There are many methods that can help individuals to learn how to relax. Strategies such as breathing exercises, sessions with a psychologist, meditation, and cognitive behavioral therapy.

Cardiovascular System

The role of the cardiovascular system in the human body is essential. When it comes to delivering oxygen and nutrients to tissues and organs, the heart and blood vessels do all the work. So it should not come to a surprise that the cardiovascular system has a large role in stress response.  

We mentioned earlier, one of the prominent symptoms of stress is the increased heart rate. When the stress hormones signal the heart to contract stronger the large blood vessels dilate and blood pressure rises. All of this brings more oxygen rich blood to the muscles and prepares them to respond to the forthcoming threat.

This is a normal response of the body to acute stress and the heart is able to adapt easily. However, when stress becomes chronic these changes can increase the risk of various cardiovascular diseases, including:

· Hypertension

· Heart attack

· Stroke

· Aortic dilatation

· Ventricular hyperplasia

· Arrhythmias

Chronic stress wears out the body and especially the heart. Every stressful situation makes the heart work harder than usual. This puts more pressure on the coronary arteries and the circulatory system as a whole. It can lead to inflammation and, even with strong acute stress, to a heart attack.

However, there are two sides to the story as normal amounts of stress on the heart from regular exercise makes the heart stronger. Regular exercise also builds collateral vessels to the heart, which reduces risk for tissue death in heart attacks. So again, some healthy stress is good, but too much of a good thing can be a bad thing. 

Endocrine System

The endocrine system plays a major part in the body’s stress response. Its role in the exchange of signals between the brain (hypothalamus) and other organs and tissues is vital. The glands and organs that take part in the stress response are:

· Pituitary gland

· Thyroid gland

· Adrenal glands

· Pancreas

When the brain identifies a stressor, such as a potentially dangerous situation, it initiates a sequence of events on the HPA (hypothalamic-pituitary-adrenal) axis. The final result of this complex process is the increased secretion of several stress-related hormones, including cortisol.

The role of cortisol in the stress response is to help the body overcome the stressful situation by providing it with more energy. Cortisol does this by bringing into use the fatty acid and glucose reserves from the liver. As a result, cortisol has the most responsibility for the sudden feelings of unusual power and strength that are often associated with stress.

Cortisol belongs to a group of steroid hormones called glucocorticoids. These hormones take part in immune system regulation. In dangerous situations, when injuries are possible, glucocorticoids help to reduce inflammation and boost the communication between the HPA axis and the immune system.

Chronic stress, however, can impair this communication and increase the risk of conditions such as:

· Diabetes

· Obesity

· Depression

· Chronic fatigue

· Immune disorders

Gastrointestinal System

Everyone is familiar with the feeling of nervousness, the so-called “butterflies” in the stomach. This is the best and simplest example of how stress can be felt in the gastrointestinal tract. The numerous neurons located in gut communicate with the brain and respond to all the changes brought on by stressors.

Long-term exposure to stress can cause a variety of problems in the gastrointestinal system. The most common symptoms of stress-related gut problems are:

· Discomfort

· Bloating

· Pain

· Nausea

The interesting thing is that these symptoms can then influence our mood and become a cause for depression, anxiety, and irritability. This shows how disrupted brain-gut communication that is caused by stress can create a perpetual string of health issues.

Different sections of the gastrointestinal system are influenced in different ways by stress. Let’s take a look now how stress affects the esophagus, stomach, and bowels.

Esophagus

Under stress, people often turn to poor eating habits, smoking, or drinking. All of these habits can damage the esophagus because they are linked to acid reflux. Esophagus spasms are also associated with stress, which will present with difficulty swallowing or a foreign body sensation in the throat, but this is not as common.

Stomach

To put it simply – stress makes the stomach more sensitive. Every kind of stomach-related discomfort is amplified by stress. This includes bloating, pain, nausea, and vomiting. Stress is also linked to increased acid levels in the stomach and stomach ulcers.

Bowels

As it was previously explained stress affects all tissues and organs. It affects both, the voluntarily, and involuntarily actions. Bowel movement belongs to the latter group of actions and is also affected by stress.

Stress can slow down the speed at which the food moves through the bowels, which can lead to painful muscle spasms and cause constipation or diarrhea. Due to all of these reasons, increased gas production can occur as well.

People who already suffer from conditions such as Irritable Bowel Syndrome (IBS), Crohn’s Disease, or Inflammatory Bowel Disease (IBD) are very likely to have their symptoms worsened by stress.

Reproductive System

Stress affects the body mentally and physically. It can cause a decrease in sexual desire and change the levels of sex hormones in both women and men.

Female Reproductive System

Stress and conditions associated with it, such as fatigue and depression are known to lower the sexual desire in women. Stress has also been associated with irregular and painful menstrual cycle.

Stress has an especially negative effect on women after childbirth. Post-pregnancy depression and anxiety are often related to stress and can have an effect on the mother-baby bonding process.

PMS (premenstrual syndrome) and stress also have a strong connection. The unpleasant symptoms of PMS, such as mood swings and bloating, can cause stress and on the flip side, stress can make PMS worse.

Menopause is a stressful period in the lives of most women and causes abnormal changes in hormonal levels. Other common symptoms of menopause, such as hot flashes, mood swings, and irritability can also act as stressors or be caused by stress.

Male Reproductive System

The autonomic nervous system stimulates the production of testosterone, which is the primary sex hormone in men. It also regulates sexual arousal by controlling the sympathetic nervous system.

The increased production and secretion of cortisol, due to acute stress, stimulates the sympathetic nervous system and increases the production of testosterone. However, this is only temporary and such changes, if they are frequent due to chronic stress, can actually lead to a decrease in testosterone levels.

Low testosterone levels equal low sex drive and can also cause erectile dysfunction.

The changes in blood pressure, blood circulation, and the functioning of the cardiovascular system due to stress can also negatively influence the functioning of the reproductive system. Low sperm count and low sperm motility are also recorded in men exposed to frequent stress.

The immune system of women and men can be weakened by stress, increasing the risk of infections and reproductive diseases.

The Final Word

Stress is a natural response to danger and potentially threatening environmental factors. As such, it is needed but, in the long run, can be hazardous to our health. Because the effects of chronic stress on the body are negative in so many ways, it is necessary to find ways to limit chronic stress.