What is inflamm-aging?

The term ‘Inflamm-aging’ is a hybrid word of course, coined by Dr Claudio Franceschi at the University of Bologna intended to raise awareness of the role of chronic, low grade inflammation in the human ageing process. Dr Franceschi is an expert on multiple aspects of human health, and in particular, on ageing and the immune system – our most important protective physiological system.

The immune system changes as we age

The paper goes into detail on how the immune system operates, and how it changes as we age. The immune system has been honed by evolution to defend us efficiently against a huge range of pathogens, or external and internal threats to our wellbeing. ‘Bad’ molecules are detected by different types of pattern receptors, but all result in triggering some form of inflammation, intended to combat the threat in an efficient way. What happens during ageing is that:

  1. The immune system becomes constantly stimulated. This is partly caused by its memory functions of previous infections, and this raises its baseline activity level.
  2. The adaptive response and specific functions of the immune system become partially paralysed.

The inflamm-aging state is caused by dysfunctional mitochondria (the cells’ powerhouse), activated DNA damage responses, elderly (or senescent) killer T immune cells, and age-related changes in gut bacteria amongst other factors.

The net effect of all this is sub-clinical, low grade, chronic inflammation as we get older.

The paper’s authors go on to ask if there could be any advantage in immune system paralysis? The answer may lie in the context of evolution – what is most rewarding for the body of an ageing organism – to destroy pathogens at any cost, or to maintain good enough bodily integrity by having the immune system permanently activated? It is likely that the latter is less energy costly, whereas maintenance of the same level of vigilance against new pathogens as in young individuals would be much more costly in energy and other resources. Besides which, the elderly immune system has already seen pretty much all the pathogens it is likely to encounter, so using the immune memory and low grade inflammation probably is more resource efficient. Downgrading the energy cost of the immune system is also following a similar path to that of muscles and bone marrow, that also shrink as we get older.

Where HRV comes in

However, as human beings, we are very precious about our individual longevity (!), so knowing how we can keep our immune systems vigilant to external infections and internal cancers is of great interest. This is where monitoring Heart Rate Variability (HRV) comes in. HRV as measured in short snapshots by apps like ithlete, tell us about the current level of parasympathetic activity in the body (specifically that to the heart).

As summarised in this earlier blog article the parasympathetic neurotransmitter acetylcholine is directly responsible for preventing the immune system from triggering inflammation and thereby modulating the immune response.  In simple terms, if your HRV is lower than usual you may have a higher level of inflammation (as happens after several intense training sessions, or an illness). Although there can be many factors impacting your daily HRV, a consistently high level of HRV over time is likely to be associated with better overall health and longevity.

What can you do?

As far as interventions to preserve immune health go, the paper’s authors speculate that although there are specific drugs such as metformin and various ant-inflammatory supplements specifically aimed at anti-ageing, their long-term effects (and side effects) are not well understood. They say therefore that general lifestyle improvements in exercise and nutrition are probably the best choice of action. Regular HRV monitoring would seem to be an excellent choice of a tool that can help you individually identify the best lifestyle changes to keep your HRV and longevity prospects improving, despite advancing age!

A final thought

Reading this paper also gave me an ‘aha!’ lightbulb moment regarding ageing individuals in society. Could it be that evolution has reduced the energy needs of elderly individuals, since, although grandparents are useful to have around to help with day to day and ad-hoc tasks and to act as a well of experience the younger generations can call upon, they as individuals are not essential for survival of the species, and should not compete with the younger generations for food and other valuable resources?

By Simon Wegerif

Immunosenescence and Inflamm-Aging As Two Sides of the Same Coin: Friends or Foes? 2018

 

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