A new study from scientists in France has revealed another devastating negative impact of insufficient physical activity — reduced immune function. The research is helping space agencies understand the physical impacts of weightlessness on astronauts, but here on Earth, these findings have important ramifications for aging populations and anyone at risk of bone loss.

Keeping our immune system in optimal working condition is especially important now because of the COVID-19 pandemic. We'll look at the details of this fascinating study, and learn about the immune cells that suffer when our bodies don't engage in weight-bearing activities.

French Study Compares Effects Of Weightlessness To Aging

In a study published in the journal of the Federation of American Societies for Experimental Biology, French scientists revealed the relationships between inactivity, aging, bone loss, and the immune system.

To conduct their research, the scientists examined three groups of mice: a group of old mice, a group of young mice, and a group of mice who reflected the effects of weightlessness or physical inactivity through a process called hindlimb unloading (HU).

The scientists measured the bone quality of the rats after three, six, 13, and 21 days. They found that limb disuse leads to a decrease of both bone microstructure and the frequency of B-cell progenitors in the bone marrow.¹

These progenitors are critical for the production of B-lymphocytes, immune cells that protect the body from foreign invaders. The study's lead author, Dr. Jean-Pol Frippiat had the following to say about these results:

“The thing to remember is that a change in bone structure, due to microgravity in space or inactivity, aging or bed-rest for medical reasons on Earth, can have serious consequences on the immune system, as immune cells are produced in bones, thereby potentially compromising host defenses. Physical activity is a good option to avoid these problems.”²

The conclusion is clear: exercise is an essential step in the production of B-lymphocyte cells that make up an important part of the immune system. Since aging naturally causes a reduction in B-lymphocyte cells, it's even more important to get regular exercise to boost your immune system as you get older.

Synopsis

A study found that a lack of physical activity causes a reduction in important immune cells called B-lymphocytes, in addition to a reduction of bone quality.

How B-Lymphocytes Develop And Function

B-lymphocytes are a type of white blood cell found in blood, lymph nodes, and spleen, tonsil, and other mucosal tissues. They comprise a majority of the bone marrow lymphocytes. B-cell development occurs in the bone marrow after lymphoid progenitor cells receive signals from bone marrow stromal cells. The study above found that it was the B-cell development process that was interrupted by a lack of physical activity.¹

B-lymphocytes play a critical role in deveolping immunity by producing antibodies to fight pathogens that the body identifies as foreign. Antibodies are specialized proteins that our bodies use to overcome viral and bacterial infections.

B-lymphocytes also offer a range of other benefits, including regulating wound healing, releasing cytokines that regulate other parts of the immune system, and influencing tumor immunity.³

Without these critical immune cells, our body doesn't have it's full ability to respond to pathogens by creating antibodies. Without sufficient antibodies, we cannot overcome illnesses and are far more susceptible to infections.

Synopsis

B-lymphocytes develop in the bone marrow when lymphoid progenitor cells receive signals from bone marrow stromal cells. Once a B-cell is developed, it responds to pathogens by creating antibodies to fight the invaders, allowing the body to prevent and overcome diseases.

What This Means To You

Exercise stimulates the production of B-lymphocytes, a core component of the immune system. This discovery adds to the list of reasons why regular exercise is critical for health and wellness. The continued threat of the novel coronavirus makes this imperative more urgent than ever.

Savers already know how important exercise is for preventing and reversing osteoporosis. Weight-bearing activities directly trigger the production of new bone. You can stream on-demand video workout classes, led by world-class certified trainers, right from the comfort of your home with SaveTrainer. SaveTrainer has everything you need to build and follow an exercise regimen that works for you.

So go out for long walks (remembering to keep a distance from other people) and perform weight-bearing exercises often. With every step, lunge, and lift, remember that you're not just strengthening your muscles and building your bones — you're also improving the efficacy of your immune system.

References

¹ https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fj.14-259770

² https://medicalresearch.com/author-interviews/space-flight-model-links-aging-osteoporosis-and-immunity/11286/

³ https://ashpublications.org/blood/article/112/5/1570/25424/B-lymphocytes-how-they-develop-and-function