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 our immune system? 

This is our body’s defence system. Cells, tissues and organs work together to protect us against bacteria, viruses, parasites and cancer. 

We are born with an innate immune system. This is our first line of defence, inherited from our parents and providing an initial barrier against infection. As we grow, a parallel (adaptive or acquired) immune system evolves. This works out how to respond to new threats and ‘remembers’ threats it has faced, so it can stop them next time. 

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 i.e. the ageing of our immune system.

What are the health implications?

  • Vaccinations for the elderly become less effective. They don't work as well, so we become more vulnerable to communicable illnesses.
  • Autoimmune disorders can develop, like MS or rheumatoid arthritis. The immune system no longer distinguishes between healthy body tissue and harmful substances such as cancer cells, viruses and toxins - and begins to destroy the healthy tissue by mistake. 
  • The ability to detect and correct cell defects reduces. This can result in an increase in the risk of cancer.
  • Areas such as the brain depend on the immune system for maintenance. If there are not enough immune cells to cope with degeneration in the brain, complications can begin to occur, including Alzheimer's. 

Can we do anything to maintain our immune system? 

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


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

  • Exercise regularly and eat nutritious food
  • Manage stress – through relaxation, meditation or breathing exercises
  • Get a good night’s sleep
  • Maintain personal hygiene (including oral hygiene)
  • Get age related vaccinations
  • 10–15 minutes of sun on your skin per day in the summer, to boost your Vitamin D, and Vitamin D supplements in winter
  • Maintain and build relationships with family and friends

Christiane Hahn, Reviewed and updated October 2017. Next review date September 2021