will regular exercise help keep your thymus from shrinking keeping immune system "younger"

Researchers (1) from University of Birmingham present evidence supporting that proposition. 

Remember  the T lymphocytes,they arise from the bone marrow and trek to the thymus where they multiply and prosper then traveling to the lymph nodes and play a essential role in immune function.Decreased immune function and shrinkage  of the thymus are well known effects of aging.

The authors studied immune function in 125 subjects aged 55-79 who had exercised regularly ( cycling) for many years.These were not elite athletes .They also studied age matched non exercisers and young adults.

The active group had higher T cell levels and higher levels of something called RTE which stands for recent thymic emigrants than did the less active control group and these levels were the same as the healthy young controls .



This finding lead some of the lay press to hype the findings in terms such as having the immune function of a 20 year old when you are 80 but only a selected aspect of immune function seemed well preserved and the authors found other aspects of the immune system (including numbers of B Cells) were the same in the active and the inactive group and not similar to the young controls.

So, 80 year old  master cyclists may not have the immune function of a 20 year old but do have some aspects of immune function better preserved than the age matched sedentary controls and there is still another reason why active aging is different from sedentary aging .

1)Duggal NA, Major features of immunosenescence including thymic atrophy are ameliorated
by high levels of physical activity in Adulthood. Aging Cell 2018 Apr 17(2) Online published March 8 2018