As we age our immune system becomes less effective, and we are more likely to fall ill. Can we do anything about this, so that we stay healthier for longer?

  • What is the immune system?
  • How does our immune system develop?
  • What happens to our immune system as we get older?
  • What are the health implications of immunosenescence?
  • Can we do anything to maintain our immune system?
  • Conclusions 

What is the immune system?

The immune system is our body’s defence system. Cells, tissues and organs work together to protect us against bacteria, viruses, parasites, and cancer (foreign antigens). It also protects against self-antigen, thereby reducing the risk of autoimmune diseases such as multiple sclerosis. 

Antigen: a substance that can stimulate an immune response.

Self-antigen: antigens that originate within the body.

Foreign antigens: antigens that originate from outside the body.

How does our immune system develop?

We are born with an innate immune system. This is our first line of defence, inherited from our parents, which gives us an initial barrier against infection. This rapid-response system surrounds infectious ‘invaders’ such as bacteria, viruses and parasites, engulfing, killing and removing them from our body.

As we mature, a parallel adaptive or acquired immune system develops which has the important ability to learn, adapt to and remember infections we have had. This learning process starts when a person’s immune system meets invaders for the first time and recognises molecules that are foreign. The cells of the adaptive immune system – such as white blood cells – learn how to respond to these new threats and ‘remembers’ them, so that it can stop them next time. This acquired immunity takes time to develop, but once it has, it responds more quickly and more effectively than after the first exposure.

 Innate & adoptive IS

What happens to our immune system as we get older?

Our immune system tends to become less efficient and less reliable as we get older. This decline is known as immunosenescence – the ageing of our immune system – and mainly involves the adaptive immune system.

At the same time, ageing is also associated with a state of chronic inflammation, termed inflammaging (‘inflamm-ageing’). Inflammaging is thought to be the basis of most age-related diseases, although the mechanisms that cause these age-related changes are not fully understood. 

Inflammaging may not be the cause of inflammatory diseases. However, it can be the trigger of clinical age-related diseases.

What are the health implications of immunosenescence?

An autoimmune disorder occurs when the body’s immune system no longer distinguishes between healthy body tissue and harmful substances such as cancer cells, viruses and toxins. This results in the body’s immune system beginning to destroy healthy tissue by mistake.

Can we do anything to maintain our immune system?

Yes. The good news is that a healthy lifestyle helps to maintain our immune system.

This table lists 11 lifestyle choices we can make to strengthen our immune systems.

The choices for a healthier lifestyle are ours!

Regular exercise

Regular exercise has been shown to have a positive effect on the immune system of older people. For example, it reduces the inflammation associated with age-related diseases. 

Good nutrition

Good nutrition helps fuel our immune system. This is particularly important for older people 
as they tend to eat less and often have less variety in their diet.


Supplementation with Zinc, Vitamin E and Vitamin D can improve immune function and resistance to infectious diseases. Older people often have low levels of these nutrients.  


A good night’s sleep (7–8 hours) is beneficial to the immune system and is associated with a reduced risk of an infection. It can improve both infection outcome and vaccination responses. 

Low stress

Limit stress. Stress produces a hormone called cortisol, which can reduce the effectiveness of the immune system. This subsequently reduces the system’s ability to fight antigens. 

Relaxation training

Relaxation training, breathing exercises and yoga may help strengthen the immune system. Mindfulness and meditation may also help, although more research is needed here.  

Social networks and positive relationships

Maintaining and building positive relationships and social networks also seem to be good for our immune system. In contrast, loneliness appears to be linked to inflammation, although this needs to be investigated more thoroughly. 


Get appropriate vaccinations to protect yourself against disease (e.g., for flu, pneumococcus, shingles (for people over 70)and coronavirus (COVID-19)). This is especially important as we age and our immune system becomes weaker. 

Good hygiene

Good hygiene, such as regular handwashing, is important to prevent infection and to reduce the strain on our ageing immune system. Handwashing, for example, helps protect us against infectious diseases such as colds, flu, measles, norovirus and coronavirus (COVID-19). 

Oral hygiene and dentists

Maintain good oral hygiene and visit the dentist regularly. That’s because a weakened immune system is less able to fight the bacteria that cause gum disease, and in turn, gum disease can weaken the immune system further. 


Even sex may help to boost our immune system, although more up-to-date research is needed to confirm this.


The body’s immune system tends to decline with age. However, there are ways we can increase the chances of our immune system functioning for longer, in particular

Reviewed and updated by Barbara Baker, October 2021. Next review date, September 2025.


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