You see, a new study published in Science Advances has found a link between muscle mass and a strengthened immune system, meaning the bigger you are the better equipped your body is to fight off infection.
Researchers infected mice with a virus called lymphocytic choriomeningitis virus (aka LCMV), which caused their muscles to release an increased amount of a signalling protein called interleukin-15 (IL-15). This was found to support the presence of muscle-infiltrating lymphocytes (MILs), which are essentially immune cells that contain high levels of T-cell factor known for its ability to identify and kill viruses and harmful bacteria.
“If the T-cells, which actively fight the infection, lose their full functionality through continuous stimulation, the precursor cells can migrate from the muscles and develop into functional T-cells,” Jingxia Wu, the study’s author explained in a statement. “This enables the immune system to fight the virus continuously over a long period.”
To take things further, the researchers repeated the experiment using mice that had been genetically modified to develop more muscle. Once infected with LCMV, the rodents released even more IL-15, and in turn, exhibited a stronger anti-viral response (read: more T-cell activity.) Put simply, the musclier mice were better at overcoming the infection.
To be clear, these findings don’t necessarily mean that burly humans have more immunity than people who have little to no muscle. It does, however, suggest a need for more research into the connection between our body composition and the immune system.