If stress becomes chronic it can have numerous detrimental effects on our health and well-being, both on a physical and psychological level. Below are just some of the conditions and health issues that have been linked with chronic stress:

Aging

Stress accelerates the aging process, affecting molecules that play a key role in cellular aging. A study published in 2004 in the November 30 issue of Proceedings of the National Academy of Sciences, found that chronic stress and perception of stress have an impact on the length of telomeres (that cap the end of chromosomes and protect the DNA from damage), the activity of telomerase and levels of oxidative stress, in healthy premenopausal women. Every time a cell divides the telomeres shorten and eventually it diminishes so much that the aged cell stops dividing. When cells die our health deteriorates. This is a common feature of growing older. Telomerase is an enzyme that replenishes a portion of telomeres with each cell division, offering a protective effect. Oxidative stress causes DNA damage, which hastens the shortening of telomeres.

The study involved 58 mothers between the ages of 20 and 50. 39 of these were mothers of a chronically ill child and the other 19 'controls' were mothers of healthy children. One of the study's key findings was that more years of care giving, resulted in shorter telomeres, lower telomerase activity and greater oxidative stress. In addition, the telomeres of women with the highest perceived psychological stress had undergone the equivalent of 10 years of additional aging, in comparison with the women across both groups who had the lowest perception of being stressed. 

“The results were striking,” says co-author Elizabeth Blackburn, PhD, Morris Herzstein Professor of Biology and Physiology in the Department of Biochemistry and Biophysics at UCSF. “This is the first evidence that chronic psychological stress—and how a person perceives stress—may damp down telomerase and have a significant impact on the length of telomeres, suggesting that stress may modulate the rate of cellular aging.”

Numerous studies have solidly demonstrated a link between chronic psychological stress and indices of impaired health, including cardiovascular disease and weakened immune function,” says lead author Elissa Epel, PhD, UCSF assistant professor of psychiatry. “The new findings suggest a cellular mechanism for how chronic stress may cause premature onset of disease. Anecdotal evidence and scientific evidence has have suggested that chronic stress can take years off your life; the implications of this study are that this is true at the cellular level. Chronic stress appears to have the potential to shorten the life of cells, at least immune cells.”

Depression

Thought to be due to the continuous release of the stress hormone cortisol by the adrenal glands, resulting in a serotonin imbalance.

Damaged Immune System

Stress can have an extremely deleterious impact on the immune system, which has wider implications for the overall health of our bodies. Stress can:

• Suppress the immune system's response to infections. There have been some studies demonstrating that people suffering from chronic stress have low white blood cell counts. This makes them more susceptible to colds and infections.
• Stress can trigger the release of cytokines (protein molecules released by the immune system to cause a reaction in other cells) in the body, causing an inflammatory response throughout the body. As a result of this the the adrenal glands produce cortisol and other glucocorticoid (anti inflammatory) hormones to suppress the immune system and inflammation reactions once the infection has cleared. However, in cases of chronic stress the cortisol levels remain continuously elevated so the immune system is constantly being suppressed.
• Conversely in some situations stress can generate an overactive immune system, increasing the risk of developing autoimmune diseases (where the immune system attacks your own body). In addition stress can aggravate the symptoms of autoimmune disorders that are already in existence.

Some studies on animals have demonstrated that excessive levels of stress had detrimental effects on the functioning of the immune system and was a contributing factor in tumour growth. Stress can also lead to self destructive behaviour (such as drinking alcohol, drug taking, poor diet), which could potentially contribute towards developing cancer.

Allergies

Stress can make allergies worse by impairing immune system function, either by suppressing it or making it overactive. Stress can also aggravate skin conditions such as: eczema, psoriasis, dermatitis and acne.

Insomnia

Stress can cause insomnia as someone who is chronically stressed will often lay awake thinking about their problems. In turn sleep deprivation then causes further stress and may result in an impaired nervous system function. Sufferers of insomnia may feel extreme fatigue, irritability and poor memory amongst other symptoms.

Memory Problems

The immediate effect of stress can prove detrimental to our short term memory. Chronic stress can cause loss of concentration in sufferers along with a tendency to be more accident prone. Some studies have demonstrated that prolonged exposure to the stress hormone cortisol can lead to the hippocampus (vital for long term memory storage) shrinking.

Sexual and Reproductive Problems

Stress can result in a decrease in sexual desire, impotence in men and an inability to orgasm in women. Stress can also diminish fertility, interfering with the ovulation process. Stress hormones adversely affect the hypothalamus (which regulates the ovaries amongst other things). Stress can also stop menstruation completely.

Pregnancy Problems

Stress can interfere with adrenal hormone levels or resistance in the arteries in a pregnant woman, which can affect the blood flow to the placenta. Stress during pregnancy has been linked with a higher risk of miscarriage, premature births and low birth weights. This is said to be due to the presence of high levels of Corticotropin- releasing hormone in the blood, which encourages early births. There has also been evidence that stress in a pregnant woman can affect the way the baby's brain and nervous system respond to stressful situations.

Cardiovascular problems 

Stress can cause blood vessel constriction, palpitations and 'sticky' blood, elevating the risk of blood clots and high cholesterol - due to the impaired metabolism of fat deposits and the release of cytokines causing damaged arteries. Stress is one of the main causes of high blood pressure. Recent studies have also demonstrated how high stress levels can increase the risk of a stroke. 

Headaches/ Joint and Muscular Pain

It has been said that stress can increase chronic pain caused by various conditions. Stress can also cause headaches, especially stress caused by emotional traumas. The stress hormone cortisol can also damage the nervous system and hamper the ability of neurons (nerve cells) to survive oxidative stress, causing nerve cell death.

Digestive Disorders

The brain and intestines are highly connected and the enteric nervous system regulates gastrointestinal motility. Stress can delay the production of stomach acid and digestive processes, slowing or even halting digestion. Prolonged stress can irritate the gastrointestinal tract and cause problems such as: diarrhoea, constipation, cramping and bloating. Stress has been linked with: Irritable Bowel Syndrome, Peptic Ulcers, Ulcerative Colitis, Crohn’s Disease and Leaky Gut Syndrome.

Eating Disorders

Stress elevates cortisol levels which can potentially cause cravings for sugary, salty or fatty foods to relieve tension. This  results in weight gain. This can then cause feelings of low self esteem in the sufferer, increasing stress levels and resulting in further comfort eating. Studies have shown that the release of the stress hormone cortisol seems to encourage the accumulation of fat in the abdominal area around the liver and other vital organs.

Stress can also cause a reduced appetite, therefore cause weight loss and in some cases an overactive thyroid.

Diabetes

Stress has been linked to diabetes as it can effect how the body utilises insulin to regulate blood glucose levels, causing persistent high blood glucose levels. During periods of chronic stress the body starts to break tissue down for energy and blood glucose levels rise. Consequently, the pancreas releases insulin - a hormone that is central to regulating the energy and glucose metabolism in the body. However, cortisol hampers the effects of insulin, leading the pancreas to pump out even more insulin. The body becomes less sensitive to its effects, resulting in insulin resistance and high blood glucose levels, both implicated in type 2 diabetes.