Newsletter #157: Exercise & The Immune System 💪🏽
Welcome to the latest humanOS newsletter! This week, we learned about the multi-dimensional effects of physical activity on the immune system (which we have touched upon previously), especially in older adults, and how exercise might even affect our response to vaccination. Timely, right? 👀 We also learned about the amount of physical activity that is associated with preventing a big killer: hypertension.
To find out more more, scroll down 👇🏼
This Week’s Research Highlights
🦠 Regular exercise lowers susceptibility to infection and boosts effectiveness of vaccines.
Researchers reviewed observational studies that examined the impact of physical activity on vulnerability to infectious diseases. They found that 30 minutes of activity, five days per week, was associated with a 31% reduction in risk of acquiring an infectious disease, and a 37% reduction in risk of dying from such a disease. They then did a similar review of randomized controlled trials and found that regular physical activity resulted in higher levels of immunoglobulin A (IgA), an antibody that plays a role in the immune defense of mucous membranes, as well as higher numbers of CD4+ T cells, which help identify invading pathogens and regulate the body’s response to them. Finally, enrollment in an exercise program was also associated with greater antibody production after vaccination. These findings, collectively, line up with a recent study showing that physical inactivity is a strong predictor of severe COVID-19.
💪🏻 Combined resistance and aerobic training reduces hallmarks of immune aging in older people.
Forty older adults (70.3 ± 5.0 years) were randomly assigned to either a control group or an exercise training group. The exercise group performed a six-week-long combined resistance and endurance training program. This regimen was carefully devised to be low-dose, so as to be accessible for elderly people. After six weeks, the exercise group showed improvements in strength capacity, but also encouraging improvements in the function of their immune system. First, they showed an increase in the ratio of CD4+ to CD8+ T-cells. The CD4+ cells are super important because they are able to “learn” about and develop specialized defenses against new invaders. As you get older, you have fewer of these types of cells, which is one reason why the elderly are more susceptible to infectious diseases, especially novel pathogens. The exercisers also showed a significant drop in several markers of chronic systemic inflammation, which is thought to interfere with immune responses by making it harder for immune cells to identify pathogens. It’s sort of like how it’s harder to hear what someone is saying on the phone when there is a lot of noise in the background. Aging is associated with a deterioration of the adaptive immune system, but exercise may help offset some of this process!
🏃 High levels of physical activity protect against high blood pressure.
A team of researchers followed a cohort of adults who were 18-30 years old at baseline (n=5115) for thirty years. They found, unsurprisingly, that physical inactivity was associated with increased likelihood of developing hypertension, and the majority of subjects developed high blood pressure as they got older. Current guidelines in the US suggest a minimum of 2.5 hours of moderate intensity exercise per week.
Maintaining that level of activity, however, wasn’t sufficient to prevent incidence of hypertension in these subjects. But meeting the high end of the guidelines (5 hours of moderate intensity exercise weekly, double the minimum) did protect against high blood pressure, and protection was even greater if that level of activity was sustained through middle age.
Podcasts We Loved This Week
- Alan Flanagan: Insulin resistance & diet. Via Sigma Nutrition Radio.
- Paul Offit: The latest on COVID-19 vaccines and their safety, herd immunity, and viral variants. Via The Drive with Peter Attia.
- Yasmeen Serhan: The consequences of vaccine nationalism. Via Social Distance.
Products We Are Enjoying
Competition Kettlebells
Competition kettlebells offer a few major advantages over the typical cast iron kettlebells that you usually see in stores. For one thing, the handle is smaller and much smoother, which reduces grip fatigue and friction for the kinds of dynamic activities that you typically do with kettlebells. They’re also uniform in size regardless of mass, which helps a lot when practicing said movements and when you transition between different weights.
Finally, they have a wide flat base, so they’re less likely to fall over if you are bracing yourself on them, like while doing planks. I’ve got this one and I am a huge fan. Definitely worth it if you train with kettlebells regularly.