Many people start exercising to improve their health. They want to feel better, feel more energy throughout the day and maybe even to lose weight. In some cases, they become addicted to the adrenaline rush and increase their workouts to several days per week.
Based on literature, long-term exercise can improve immune system function and offer protection against many diseases and health issues (heart disease, cancer, diabetes, hypertension, high cholesterol and more).
But, what are the short-term effects of exercise to the body? Are we more exposed to damage and sickness immediately after training? Is it possible that training itself is harmful to the body and weakens it? How do you handle the problem? Should we take supplements or perhaps is the answer to all these questions found in our diet?
What is the effect of exercise on the immune system?
The effect of exercise on the immune system should be divided into two categories: long-term and short-term effects.
1) Long-term effects - When we examine the effect of physical training on the immune system in the long term, we can see, based on numerous studies, that regular physical activity reduces the risk of many diseases and types of cancer, improves cholesterol levels, contributes to weight loss and increases life expectancy. In the long term, exercise has many advantages and is recommended for everyone.
2) Short-term effects - Despite the beneficial effects of training over a period of years, it is important to understand that the immediate effects of exercise on the immune system may not be beneficial. When performing intense physical training over 45-60 minutes, several processes occur in the body in parallel.
The body actually suppresses the immune system's function while creating components that may harm the body. What does this mean? a) Creating hazardous substances in the body during exercise – During intense/prolonged exercise, muscle cells form oxygen derivatives called "ROS” (reactive oxygen species) and materials that are defined as "Free Radicals." These substances are secreted from the muscle into the bloodstream, creating a condition called "oxidative stress." This increases acidity in the body that may damage tissues, tendons, ligaments and intracellular organelles. As exercise intensifies or lengthens, so may oxidative stress. b) Immune suppression – When exercising, several physiological processes occur in the body including increases in body temperature, blood pressure, breaths per minute, heart rate and more. The body "thinks" it is in a state of flu, but it also knows there is no flu present and avoids starting an immune response. Therefore, the body secretes hormones that suppress the immune system.
Example: Cortisol hormone release (the stress hormone). This process is normal while training, but the problem may occur after exercise when the immune system does not immediately return to a normal level. This can leave the body more vulnerable to oxidative stress and free radical damage. It also leaves us more susceptible to germs and viruses in our immediate environment.
The most popular disease among athletes is an upper respiratory infection. Why? Because this is the first place in which germs/viruses penetrate the body. This is why athletes, especially endurance athletes (runners, tri-athletes, cyclists), often suffer from colds, sore throats and runny noses while training for competitions.
External help is important to strengthen the body as well as better prepare for threats from the inside (oxidative stress) and the outside (germs, viruses, bacteria).
How we can protect the body immediately after a workout? Answer: Eat carbohydrates. Eating carbohydrates encourages the secretion of insulin hormones into the blood. Insulin lowers Cortisol levels that suppress the immune system. After training, but before eating carbohydrates, Cortisol levels continue to elevate in the blood. Hence, the best way to reduce Cortisol's suppression of the immune system after exercise and quickly restore immune system function, is to eat quick-absorbing carbohydrates.
Examples: fresh fruit (banana, apple, orange, etc.), dried fruit (date, fig, apricot, etc.), fruit juice, sandwiches and more.
Note- After an intense/long workout and/or competition, the recovery of the immune system may take a few days until you reach full function. Therefore, it is important to eat something rich in carbohydrates immediately after the exercise, even if you do not feel hungry.
How does the body deal with post-exercise suppression of the immune system in the long term? In the long term, the body learns to create its own natural antioxidants, chemicals that improve immune system function. This is how we explain the positive effect of physical activity on our health in the long term. However, there are two cases in which, according to literature, people may be more vulnerable to impairment of the immune system following exercise: 1) In the beginning stages of training (getting in shape) 2) During periods of overload training - preparation for competitions, training camps, etc.
Should we use high-dose antioxidant supplements? One of the proposals to strengthen the body is to take supplements, or high doses of antioxidants (e.g. vitamin C, vitamin A, vitamin E, etc). Indeed, it makes sense, but research in the area discovered that it had an opposite effect on the immune system in the long term. Researchers found that high-dose antioxidant supplements prevent the body's production of natural antioxidants. Meaning, it damaged the adaptation reaction of the body to exercise in the long term.
How can we help to protect our body? In the last decade, there have been a number of investigations on improving the body's immune response after training. The purpose was to determine how the combination of antioxidant-rich foods and beverages can help protect the body.
This idea has also been tested among amateur and professional athletes. The aim was to help the athlete's body cope with the rush of physical training and improve immune function. Many foods have been studied in this context with the goal of allowing combinations of healthy, nature-inspired foods and drinks in the menu. Foods high in natural antioxidants include pomegranates, oranges, lemons, broccoli, tomatoes, beets, berries, wine, coffee, green tea and more.
Summary Exercise is good for everyone's health. It improves the function of the immune system in the long term. However, in the short term, intense exercise may suppress the immune system and create harmful components (free radical and ROS). Therefore, it is very important to eat carbohydrates immediately after the exercise and to combine antioxidant-rich foods in our daily menu.