Exercise as a countermeasure for latent viral reactivation during long duration space flight

Abstract

Latent viral reactivation is a commonly reported manifestation of immune system dysregulation during spaceflight. As physical fitness and exercise training have been shown to benefit multiple arms of the immune system, we hypothesized that higher levels of preflight physical fitness and/or maintaining fitness during a mission would protect astronauts from latent viral reactivation. Standardized tests of maximal strength, muscular endurance, flexibility, and cardiorespiratory fitness (CRF) were performed in 22 international space station (ISS) crewmembers before and after a ~6month mission. Reactivation of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and varicella zoster virus (VZV) was determined in crewmembers and ground-based controls before, during, and after spaceflight. Crewmembers with higher CRF before spaceflight had a 29% reduced risk of latent viral reactivation compared to crew with lower CRF. Higher preflight upper body muscular endurance was associated with a 39% reduced risk of viral reactivation, a longer time to viral reactivation, and lower peak viral DNA concentrations, particularly for EBV and VZV. Latent viral reactivation rates were highest in crew with lower preflight CRF and higher levels of CRF deconditioning on return to Earth. We conclude that physical fitness may protect astronauts from latent viral reactivation during long duration spaceflight missions. K E Y W O R D S astronauts, cytomegalovirus (CMV), Epstein-Barr virus (EBV), functional fitness tests, immune dysregulation, varicella zoster virus (VZV), V O 2max 2870 |

The immunological case for staying active during the COVID-19 pandemic

“…Physically active individuals also exert better control over their latent viral infections, even during periods of isolation and confinement. For instance, recent work from our laboratory demonstrated that astronauts with increased levels of cardiorespiratory fitness and skeletal muscle endurance were ~40% less likely to reactivate a latent herpesvirus during a 6-month mission to the International Space Station (ISS), particularly if they were able to maintain their fitness levels on the ISS (Agha et al, 2020). Even in astronauts who did reactivate a virus, copies of viral DNA were fewer in the fitter astronauts indicating that they were less contagious than their less-fit counterparts.…”

Kick start training during the COVID-19 pandemic - Challenges of the sporting community

“…Exercise in general can mitigate the negative effects of stress to maintain immune function, particularly during prolonged periods of isolation and confinement. It has been shown that astronauts in space travel for nearly 6 months with extreme isolation who had a higher pre-flight cardiorespiratory fitness and muscle endurance had a better immune response compared to astronauts who were not fit [22].…”

Does Longer Leukocyte Telomere Length and Higher Physical Fitness Protect Master Athletes From Consequences of Coronavirus (SARS-CoV-2) Infection?

“…A transient exercise-induced immunosuppression described above may result in a transient post-exercise "open-window" of diminished ability to combat an infection, and during that period some situations representing an increased risk (i.e., going to supermarket) should be avoided. Nevertheless, in times as these of a pandemic and social isolation, it is important to avoid deconditioning as it will weaken the immune function and diminish the defense against viral infections (Agha et al, 2020). So, protect yourself, be healthy and keep exercising at moderate intensity for your health.…”