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Stress may weaken the immune system, increases the risk of illness - MyHealth


Stress may weaken the immune system, increases the risk of illness


Medically Reviewed By
Dr. Ragiinii Sharma

Written By Prekshi Garg
on Jun 17, 2022

Last Edit Made By Prekshi Garg
on Mar 14, 2024


As you age chronologically our body and it’s functions also change and slow down. The same thing happens with our immune system as well. The ageing of the immune system along with our chronological age is known as “Immunosenescence”. Age related immune system deterioration can lead to different health problems like cardiovascular diseases, delayed response to vaccines, and cancer. While age is an unavoidable factor, stress can lead to early ageing of your immune system. In this article, let us discuss about how stress and immunosenescence are related to each other.

harmful effects of stress

Relationship Between Stress and Immunosenescence

The researchers from the University of Southern California (USC) observed that the people with the same age can have different immunological ages. This made them suspect that there must be another factor apart from age that is also responsible for the ageing of the immune system, otherwise people of the same age should have an immune system of the same age. Therefore, the researchers of the University of Southern California (USC) analysed the data obtained from the Health and Retirement Study (HRS). The HRS is a large national representative survey of people above 50 years of age conducted in the United States.

The researchers of the HRS group focused on the different stressors that the participants of the study may have faced. It included stressful life events as well like discrimination, job loss, unfair treatment, lifetime trauma, having a close relative being diagnosed with life threatening illness, financial strain, or any other factor that can trigger stress. 

In order to identify the effect of stress on the ability of your immune system to fight against invading bacteria, and viruses, the HRS researchers started collecting the blood samples of the patients involved in the study. The blood samples of the participants were used to count the number of different types of immune cells. This was the first large national survey to collect detailed information about immune cells. 

The HRS study comprised approximately 5744 participants who answered the questions of the survey and also provided with their blood samples. According to the observation made by the researchers of the HRS group, the participants of the study who experienced more stress during their life had a lower proportion of naive or new T cells in their blood sample. Naive T cells refer to the new group of T cells that act against the new foreign invaders that have not yet been encountered by their body’s immune system. The researchers also observed that the blood sample of such participants contained a high proportion of late differentiated T cells. The late differentiated T cells refer to the group of T cells which have depleted their ability to fight the invaders and can cause harmful inflammation due to the secretion of certain proteins. The naive T cells and the late differentiated T cells are the main factors of your immune system that determine the age of your immune system. Having a lower proportion of naive T cells and higher proportion of older T cells in your blood sample shows that your immune system has an increased life span.

The researcher also considered that the immune system ageing can be due to unhealthy diet and sedentary lifestyle. Therefore, the diet of the participants was modified and regular exercise was also included. Still, the connection between stress and increased immune system ageing did not prove to be as wrong as it was earlier expected.

Another factor according to the USC team that can lead to increased immune system ageing was the exposure to a common asymptomatic virus, known as cytomegalovirus (CMV), that is also known to speed up the ageing process. This connection reduced the link between stress and immunosenescence. The researchers found that the CMV virus stays dormant in your body and can increase its multiplication due to stress. The increased CMV in your body will put more force on your immune system, so that it can increase its resources for controlling the reactivated virus in your body. Thus, controlling sustained infection leads to the use of naive T cells ultimately leading to the exhaustion of the T cells that circulate in your body. This causes chronic inflammation in your body which is a major contributor of age-related disorders in humans.

Outcome Of The Study

The research group clarified that their study found a strong association between social stress and elevated ageing of your immune system. Their study also highlighted some key tips that can help in slowing down the ageing process of the immune system. These tips include:

  • Effective management of stress
  • Improve lifestyle habits
  • Have a healthy and balanced diet
  • Quit smoking and drinking
  • Regular exercise
  • Development of effective vaccine against cytomegalovirus 

People with a younger immune system are more capable of fighting with the invading microorganisms generating better immunity against vaccines. This also explains the different response of people’s immune system to COVID-19 vaccines. This study might act as a landmark for the scientists to better analyse the age related disparities in the field of health and illness. 


Increased ageing of the immune system can be due to stress triggers you face during your life. The study conducted by the group of HRS researchers, forms a strong link between stress and immunosenescence. However, this aspect needs to be researched more as epidemiological studies alone are not sufficient to establish a cause and effect relationship. Further research also needs to be carried out to see whether improvement in stress reduction and management or lifestyle modifications will play a vital role in improving immune system ageing. More research should also be done to know the interaction between stress and latent pathogens like CMV in order to better evaluate their cause of illness and death. The HRS group is also evaluating the additional data to examine the effect of other factors like childhood adversity on immune system ageing. 

Now that you know how increased stress might affect your body’s response to infections, make sure that you attempt to manage and reduce your stress effectively.

Frequently Asked Questions (FAQs)

  • Can stress lead to a weaker immune system?

According to the current study, stress can adversely affect your immune system leading to increased ageing of your immune system.

  • What are the natural ways to increase the effectiveness of the immune system?

Some of the ways that can help increase your immune system effectivity include:

  • Effective management of stress
  • Lifestyle modifications
  • Have a healthy and balanced diet
  • Quit smoking and drinking 
  • Regular exercise


  • Why do people respond differently to the COVID-19 vaccine?

The response of an individual to any vaccine depends greatly on their immune system. People with an aged immune system will ultimately have a delayed or poor immune response against the COVID-19 vaccine.

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