What is stress?

Stress can have a significant impact on your physical and mental health. In this section, we discuss the symptoms and consequences of stress.

Stress is something that we all feel at times. But how do you know the difference between good stress and bad stress?

Life can throw all kinds of stressful situations at us, and low-level stress can be helpful. We look at what stress does to the body, what you can do to help cope with stressful events, and ways to deal with feelings of stress or burnout. 

What is stress?

Stress is the body’s reaction to feeling threatened or under pressure [1]. It is also sometimes known as the fight, flight, or freeze response. 

Stress is a basic survival instinct that we all share and has followed us through evolution.

The stress response works like this: 

  1. When faced with a potentially dangerous situation, the fear centre in the brain (the amygdala) sends signals to the hypothalamus (our brain’s command centre) and activates our sympathetic nervous system (SNS).
  2. SNS activation results in a release of the hormones cortisol and adrenaline - the stress hormones.
  3. Stress hormones travel around the body, communicating to bodily processes that need to increase (such as heart rate) or decrease (such as digestive processes).

Present-day modern stressors could include:

  • Your daily commute
  • Work pressure
  • Childcare
  • Financial stress

You can read more about the causes of stress in the top ten causes of stress section.

What are the symptoms of stress?

The symptoms of stress can vary from day-to-day and situation to situation. Different people may find certain situations more stressful than others.

Common symptoms of stress include:

  • Feelings of being overwhelmed
  • Anxiety
  • Racing thoughts
  • Panic
  • Difficulty concentrating or focusing 
  • Poor memory
  • Lack of clarity 
  • Poor sleep pattern
  • Being or feeling isolating
  • Poor eating patterns
  • Fear and constant worry 
  • Engaging in risky behaviour as a form of escapism 
  • Reduced libido 
  • Irritability or a shorter fuse
  • Digestive symptoms such as loose stools, constipation, or nausea
  • Headaches
  • Aches and pains

Stress may also make you feel more run-down and more likely to pick up more infections. This is because chronic stress is associated with lowered immunity. The longer stress continues, the more the stress response goes from having a positive effect, to becoming potentially detrimental [2].

If you pick up a virus, such as an upper respiratory tract virus, you may have more severe symptoms than someone who isn’t as stressed [3]. 

Does stress cause cancer?

There is no clear evidence from research that stress causes cancer [4]. However, when stressed, you may engage in more unhealthy lifestyle behaviours which are associated with cancer. 

Unhealthy lifestyle behaviours that can increase your risk of cancer include:

  • Poor diet 
  • Becoming obese
  • Smoking 
  • Doing less exercise
  • Drinking more alcohol

If your stress affects your sleeping habits, poor sleep may increase your risks of certain health conditions. 

You can read more about how your sleep affects your health in our is sleep risking your health blog.

Low levels of psychological distress, however, are not associated with cancer death [5]. 

Will stress kill me?

A small amount of stress can be healthy. It is a natural response to feeling under threat, and it can sometimes help you.

Ways stress can be good for you include:

  • Helping you to stay safe
  • Motivating you to help achieve work goals
  • Motivating you to achieve home and family demands

Cortisol levels in your blood change throughout the day, enabling you to be more focused and active when needed. Upon waking, your cortisol hormone is generally at its highest, helping you to wake from your sleepy state.

Stress only becomes problematic when it becomes too high. If you frequently feel stressed, your body may be releasing too much cortisol, leading to unnecessary and unpleasant symptoms and a reduced sense of wellbeing. 

Chronic stress can wreak havoc on your body due to high cortisol continuously preparing your body for action. 

Consequences of chronic stress on the body include:

  • Impaired immune function
  • Sleep disturbances
  • High blood pressure
  • Greater risk of cardiovascular diseases
  • Impaired regulation of blood sugar
  • Changes to dietary habits
  • Food cravings 
  • Mood changes
  • Depression 
  • Memory problems 
  • Bodyweight changes

Read more about the effects of stress in our how does stress affect your body section.

Are your cortisol levels affecting your health and wellbeing?

If you’re unsure whether your cortisol levels could be affecting your wellbeing, our Cortisol Saliva Stress Test can help.

These simple at-home saliva tests can measure your cortisol levels, helping you to understand whether your stress levels are having a negative impact on your health and wellbeing.


  1. nhs.uk. 2021. Stress - Every Mind Matters. [online] Available at: <https://www.nhs.uk/every-mind-matters/mental-health-issues/stress/> [Accessed 21 December 2021].
  2. Segerstrom, S. and Miller, G., 2004. Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry. Psychological Bulletin, 130(4), pp.601-630.
  3. Cohen, S., Doyle, W. and Skoner, D., 1999. Psychological Stress, Cytokine Production, and Severity of Upper Respiratory Illness. Psychosomatic Medicine, 61(2), pp.175-180.
  4. Cohen, S., Doyle, W. and Skoner, D., 1999. Psychological Stress, Cytokine Production, and Severity of Upper Respiratory Illness. Psychosomatic Medicine, 61(2), pp.175-180.
  5. Heikkila, K., Nyberg, S., Theorell, T., Fransson, E., Alfredsson, L., Bjorner, J., Bonenfant, S., Borritz, M., Bouillon, K., Burr, H., Dragano, N., Geuskens, G., Goldberg, M., Hamer, M., Hooftman, W., Houtman, I., Joensuu, M., Knutsson, A., Koskenvuo, M., Koskinen, A., Kouvonen, A., Madsen, I., Magnusson Hanson, L., Marmot, M., Nielsen, M., Nordin, M., Oksanen, T., Pentti, J., Salo, P., Rugulies, R., Steptoe, A., Suominen, S., Vahtera, J., Virtanen, M., Vaananen, A., Westerholm, P., Westerlund, H., Zins, M., Ferrie, J., Singh-Manoux, A., Batty, G. and Kivimaki, M., 2013. Work stress and risk of cancer: meta-analysis of 5700 incident cancer events in 116 000 European men and women. BMJ, 346(feb07 1), pp.f165-f165.

Related tests

Cortisol Saliva Stress Test

Our popular cortisol saliva test helps you understand your stress levels and adrenal function by testing your cortisol levels 4 times over the course of a day

  • Results estimated in 3 working days