YOUR FITNESS MIGHT BE TELLING YOU SOMETHING ABOUT YOUR IMMUNE AGE!
Wednesday, 14 October 2026 • THE LONG GAME
Q: Is physical fitness connected to changes in the ageing immune system?
A: A small three-year observational study found associations between declining physical fitness and changes in immune-cell populations related to ageing. It did not prove exercise reverses immune ageing.
THERE IS MORE TO FITNESS THAN STEP COUNTS
It’s perfectly possible to report the same weekly activity but have changes in strength or cardiovascular capacity. The researchers looked at measured capabilities, not just how often people said they exercised.
WHAT THEY FOUND
A March 2026 study followed 49 clinically healthy older adults over three years, looking at fitness, strength, body composition, immune cells and inflammation markers. Fitness and strength declined while some immune-cell profiles shifted in ways associated with ageing; certain familiar inflammatory markers were relatively stable.
WHY THIS IS INTERESTING
The immune system changes as we age, including different T-cell populations. The association with measurable fitness gives researchers a reason to explore how movement, muscles, metabolism and immune function interact.
WHAT IT DOESN’T PROVE
There was no randomised programme showing that a particular workout restores a younger immune system. A 49-person observational study cannot prove cause and effect. Anyone selling an “immune-age reversal” programme on this evidence is getting rather ahead of the science.
A USEFUL PRACTICAL QUESTION
Instead of tracking only whether you did a walk, consider whether familiar hills, resistance exercises or everyday physical tasks feel different over time. Appropriate strength and cardiovascular activity can be useful for fitness, but this paper doesn’t prescribe a treatment.
MY TAKEAWAY
Ageing isn’t a single dial that moves in one direction. The relationship between strength and immune cells is the sort of question worth following — without turning a small study into a miracle claim.
AVAILABILITY, COST & LIMITATIONS
Open-access study. General exercise requires no particular paid plan; physical activity suitability differs by person.