Everyone knows that exercise has a protective effect on health and is key for a long life. New research shows it can reduce the risk of severe complications from COVID-19.
This is important because early surveys show that Americans have become more sedentary and less fit since the start of lockdowns in the U.S. Citizens in other developed countries affected by the coronavirus are certain to fair similarly, with a drop in daily step counts, less aerobic capacity, a decrease in muscle mass, and increase in body fat.
While it may be challenging to maintain fitness with gyms closed, there are plenty of ways to train so that you protect yourself from illness. This article will explain why exercise is so important for your immune system and give you work out tips for getting your sweat on.
How Does Exercise Support Immunity?
We’ve known for years that physical activity elevates your immune system by improving the body’s natural antioxidant system. Studies show that those who exercise tend to suffer fewer infections than sedentary individuals. A new review from the University of Virginia shows that regular exercise reduces the risk of acute respiratory distress syndrome, a major cause of death in patients with COVID-19.
Exercise has a preventative effect by raising levels of an endogenous antioxidant enzyme known as superoxide dismutase that is protective against the virus. This potent antioxidant hunts down harmful free radicals, protecting our tissues and helping to prevent disease. Our muscles naturally express superoxide dismutase (SOD), releasing it into the circulation to allow binding to other vital organs, but its production is enhanced by cardiovascular exercise.
SOD is protective against several chronic diseases as well, including acute lung disease, heart disease, high blood pressure, kidney failure, diabetic retinopathy, and osteoarthritis.
What Type of Exercise for Immune Support?
Both aerobic and strength training are certain to support the immune system. But due to a greater body of research, scientists tend to recommend moderate endurance exercise for immune benefits. For example, a series of studies in mice show that moderate endurance training protects mice from death by influenza. In humans, 10 months of regular endurance exercise improves flu vaccination responses in older adults who are immune compromised. Exercise also extended the protective effect of a flu vaccine, raising levels of antibodies that fight off disease throughout the flu season.
There is a lack of studies on the impact of strength training, but researchers theorize that this type of exercise can also improve immune response and it certainly reduces risk of underlying diseases that put you at risk of serious complications from the coronavirus like insulin resistance and obesity. Additionally, muscle is protective against death, providing a reservoir for the body when things go wrong. Muscle mass is consistently linked with longevity, especially in people with cancer and other chronic diseases.
Workout Guidelines for Immune Support
What follows are workout guidelines to consider when designing training programs for immune support.
Do Smart Cardio
Experts recommend that 30 minutes of moderate intensity training daily will raise SOD and promote general fitness. Brisk walking or biking are great options. Hiking in nature is especially effective, but if all you’ve got is pavement, the key is to enjoy your walk.
Longer more intense workouts may also be beneficial as long as you are able to recover effectively. There is some evidence that very long duration training (2.5 hours or more) can negate the protective effect, though current evidence shows it is unlikely to make you more at risk of infection than a sedentary lifestyle.
Interval training is also an option that will raise antioxidant status and promote fitness. For example, a low-volume sprint workout like the Wingate protocol (four 30-second sprint repeats on a bike with 4 minutes active rest) may support neuroendocrine function while improving mood due to release of beta endorphins and dopamine that make you feel good. A 20-minute cycle workout consisting of 8-second intervals with 12-seconds easy pedaling is another option.
Prioritize Strength Training
Strength training is important to maintain muscle and fitness, while minimizing the stress response that makes you susceptible to illness. This can be a little tricky if the gym is closed. The good news is that with a minimum of gym equipment and a few body weight exercises, you can get a good workout that will allow you to build strength and muscle.
With a few resistance bands or some dumbbells it is possible to do squat variations, push-ups (or elevated push-ups on a counter or edge of a sofa), lunges, step-ups, overhead press, bent over rows, and biceps and triceps curls. Get a suspension trainer and you can add inverted rows and many variations to the already mentioned motions. Add a stability ball and you can do hamstring curls and core exercises.
Regarding rep ranges, this is a great time to favor volume to encourage muscle and connective tissue adaptations. Higher volume sets are also ideal when your overload options are limited to body weight or resistance bands. To start, use rep ranges of 12 to 15 for 3 to 5 sets in a circuit format in which rest periods are the length of time it takes to transition from exercise to exercise.
After several weeks once adaptations set in, you can either increase your resistance and lower your rep ranges, or if you lack equipment, bump your volume up with higher reps in the 15 to 20 range for greater metabolic stress. The goal is to keep the body adapting until you can get back in the gym and increase your intensity with heavier loads.
How many sessions per week?
Four workouts lasting 45 minutes to an hour will do the trick for most people. This will allow complete muscle recovery while supporting immunity and wellness. That said, if you are not working and have the time, training every day is an option as long as you are able to recover optimally. In this case, design two or three workouts using different exercises that you can rotate through each day of the week.
Use Mind-Body Exercise
Exercise that requires you to get your body in tune with your mind can also support the immune system. There are plenty of free online mind-body classes available so it’s a great time to incorporate this type of exercise into your routine.
Yoga has been shown to improve immune markers in the blood while practitioners of the martial art judo have lower levels of inflammation that predispose you to illness. Other mind-body practices that will likely convey immune benefits include most martial arts, deep breathing, regular stretching, or foam rolling, and dancing.
Meyer, J., et al. Changes in physical activity and sedentary behaviour due to the COVID-19 outbreak and associations with mental health in 3,052 US adults. Cambridge Open Engage. 2020. Published Ahead of Print.
Yan, Z., Spaulding, H. Extracellular superoxide dismutase, a molecular transducer of health benefits of exercise. Redox Biology. 2020. 32: 101508.
Zhu, W. Should, and how can, exercise be done during a coronavirus outbreak? An interview with Dr. Jeffrey A. Woods. Journal of Sport and Health Science. 2020. 9(2), 105-107.