What is stress? Can too much stress make us ill? Might some stress keep us healthy?

  • What is stress?
  • Symptoms of stress
  • Can too much stress make us ill?
  • Possible indirect health benefits
  • Is there a link between stress and cancer?
  • Are some of us more genetically predisposed to stress?
  • Might some stress keep us healthy?
  • Conclusions

What is stress?

Stress is a feeling of being under too much emotional or physical pressure.

This pressure becomes stress when we feel we can't cope. Each of us perceives and deals with stress differently. That’s why sometimes the same potential stressor can have opposite effects for two individuals. For example, one person may perceive taking on a new responsibility at work as stressful, whereas another person may see it as a stimulating challenge.

Symptoms of stress

Our body, perception, mental state and behaviours are all affected by stress. Common signs of stress are:

Stress Symptoms 

Can too much stress make us ill?

Stress and illness

Researchers have found a link between our brain and our immune system, suggesting that how we feel mentally can influence our physical health. They describe the study of this interconnection as psychoneuroimmunology (PNI). 

For example, a strong association has been found between long-term stress and the onset of gastrointestinal disorders such as inflammatory bowel disease and irritable bowel syndrome.

Overall, sustained stress has been found to influence our hormones, our immune system, our endocrine system and our cardiovascular system. It is therefore not surprising that sustained stress is likely to affect our physical health.

For example, a study of more than 10,000 civil servants reported in the BMJ in 2011 that those who experienced chronic work stress were at significantly greater risk of metabolic syndrome – a cluster of risk factors that increase the risk of both heart disease and type 2 diabetes.

While a large-scale, long-term study in Sweden, published in 2019, which followed 136,000 patients over 27 years, concluded that stress-related disorders are closely associated with several types of cardiovascular disease


Burnout is a syndrome that occurs from chronic stress at work. It displays psychosocial symptoms such as emotional exhaustion and loss of energy, detachment from work and clients, a feeling of personal or professional inadequacy, lowered productivity and reduced coping skills.

A systematic review in 2017 suggested that burnout was also one of the main causes of medical conditions such as hypercholesterolemia, coronary heart disease, type 2 diabetes, hospitalisation from cardiovascular disorder, musculoskeletal pain, headaches, long-term fatigue, gastrointestinal issues, respiratory issues and mortality under the age of 45. 

Uncontrolled stress

Research suggests that when a person is stressed, the hormones and neurotransmitters that are released in the brain are stronger and more prolonged when the person thinks that they are unable to cope with the stress, i.e., they are in a state of ‘uncontrolled stress’.  In a state of uncontrolled stress, the telomeres in our chromosomes are shortened, which can shorten life expectancy

A person can move from uncontrolled to controlled stress in a particular situation, even though the situation itself does not change.

The most common condition for taking control of stress is to change current lifestyle choices.

Stress and ageing

It also seems that psychological stress affects people’s health in a similar way to ageing, and that chronological ageing, combined with chronic stress, accelerates the ageing of our immune system

Stress and ageing now consistently appear in the literature as factors that act upon the immune system in a way that is often damaging.

Possible indirect health effects

Stress may also lead to a change in health practices and changes in the way people follow medical advice. For example, when the spouse or partner of an elderly person dies, routines and habits are often disrupted. These disruptions may cause changes in healthy eating habits or an increase in drinking, which may lead to non-restful sleep. This is a particular problem if the spouse or partner has a pre-existing health problem.

This fits with information from the Mayo Clinic, which suggests that stress may have both a direct health effect (e.g., changes to blood pressure) and an indirect health effect (e.g., when stress leads to smoking or overeating). For example, a small 2017 study with 60 nicotine-dependent smokers, found that smoking was associated with stress response. 

A 2011 meta-analysis, updated in 2013, showed that stress, anger, and depressed mood can act as acute triggers of major cardiac events. The analysis found a 2.5-fold increased risk of acute coronary syndrome preceded by stress, while stress in the workplace was associated with a 1.3-fold increased risk of coronary heart diseases.

However, it is chronic (long-term) stress rather than acute (serious one-off events) which is associated with more serious healthrisks, such as high blood pressure, heart disease and diabetes. 

Loneliness and social isolation are also common causes of chronic stress. They activate the hypothalamic-pituitary-adrenocortical (HPA) axis, which is linked with the development of cardiovascular disease. 

Loneliness and social isolation increase mortality risk as much as smoking or alcohol consumption and more than physical inactivity or obesity.

Is there a link between stress and cancer?

According to a 2013 meta-analysis of studies involving 116,000 European men and women and to the US National Cancer Institute, no link between work-related stress and cancer or stress and cancer seems to have been proven.

The US National Cancer Institute reported finding only weak evidence that stress can cause cancer, noting that associations were possible due to the indirect effects of stress (as explained above). For instance, people under sustained stress may be more likely to smoke, overeat or increase their alcohol consumption, which can lead to an increased risk of cancer. 

Stress management is essential for both healthy people and for cancer patients.

As explained earlier, the harmful effects of stress are greater when some one thinks they are unable to cope with the stress (uncontrolled stress). There is also evidence to suggest that stress can lead to tumour growth once someone has cancer. In other words, stress may not cause cancer, but it may accelerate its progression. If this is correct, then managing and controlling stress can be important to consider for those diagnosed with cancer. 

In addition, a Chinese review of more recent evidence (2020) suggests that chronic stress can both induce tumorigenesis (the formation of a tumour) and promote cancer development

Cancer formation and cancer development are potential effects of stress we will keep under review.

Are some of us more genetically predisposed to stress?

Some research has suggested that our genes may influence not only how easily we become stressed, but also how well we cope with stress. However, the ‘genetic underpinnings’ of anxiety and stress-related disorders are poorly understood, meaning that more research is needed in this field of genetics.

Might some stress actually keep us healthy?

Hormesis is a biological phenomenon whereby a beneficial effect (improved health, stress tolerance, growth or longevity) results from exposure to low doses of an agent that is otherwise toxic or lethal when given at higher doses. 

The theory of hormesis suggests that repeated, but not continuous, mild stress helps keep our immune system resilient. So far, this theory relies on evidence from trials in creatures like rats rather than humans, so may or not be applicable in practice.

However, in evolutionary terms, hormesis makes sense. For most of our time on earth, humans have been susceptible to stress, for instance, hunting or being hunted, experiencing famine and drought, working very long hours with few holidays, being vulnerable to wars and crimes. If we were to fall ill quickly as a result of these kinds of stress, then the human race probably would not have survived as long as it has. We're a resilient and adaptable species.

To research whether mild stress is beneficial, examples of mild stress such as ischaemic conditioning (a medical technique to protect an organ or a limb from further damage by repeatedly and temporarily cutting off its blood flow), sauna bathing and fasting are being investigated in preclinical and clinical trials, to explore their potential value in preventing myocardial infarction (heart attack) or cardiovascular disease, particularly in elderly people. However, there are challenges to using mild stress, as mild stress can develop into severe stress. There is also uncertainty around what age and for how long mild stress can safely be used


  • Stress is a feeling of being under too much emotional or physical pressure.
  • Stress can trigger changes in the body’s hormones, immune system, endocrine system and cardiovascular system.
  • Repeated, but not continuous, mild stress is probably good for us and helps build our resilience.
  • However, chronic stress (i.e., significant, prolonged stress) can increase the likelihood of both mental and physical illness (including bowel disorders, heart attack, type 2 diabetes and vulnerability to catching infection), as well as increasing the adoption of unhealthy ‘coping’ habits, such as smoking or drinking too much.
  • Where people feel unable to cope with stress (uncontrolled stress), there appears to be an increased health risk.
  • Whether stress can cause cancer (as opposed to encouraging behaviour that increases the risk of cancer, like smoking and excessive alcohol consumption) isn’t yet clear.

You may also be interested in information about coping with chronic stress


Other relevant articles on the Age Watch website:

Reviewed and updated by Norin Begum, October 2020. Next review due September 2024.