How regular physical activity and diet affect immunity

Immunity is the ability of the human body to defend itself against infections and diseases. The immune system is made up of different cells, tissues and molecules. The immune system is generally classified into 2 main “arms” – nonspecific and adaptive (specific and acquired) – but all components work in synergy and function in a highly synchronized manner.

Non-specific cells can respond very rapidly but do not have their own specificity (ie the same response to all challenges), while adaptive cells have antigenic specificity and “memory” but take much longer to develop after initial exposure to an infectious agent, although the rate and the size of this system increases with subsequent exposure to the same infection.

Immune function changes throughout life, with differences that are evident at certain stages. Regular exercise as well as eating habits are important factors that have a significant impact on how well the immune system responds to challenges at all stages of life.

Physical activity and the immune system

Regular moderate aerobic activity is promoted as a strategy to stimulate the body’s immune function, or more simply:

  • Physical activity leads to faster release of bacteria from the lungs and airways. This reduces the chance of catching a cold, flu or other illness.
  • In addition, exercise causes changes in the antibodies and white blood cells (cells of the body’s immune system that fight disease). These antibodies circulate faster during exercise and speed up metabolism, so they can detect infection in your body faster and fight it.
  • A brief rise in body temperature during and immediately after exercise can prevent the spread of bacteria. This rise in temperature can help the body fight infection better.
  • In addition to all this, exercise slows down the release of stress hormones. Some of these hormones increase the chance of getting sick. Therefore, less stress hormones – better immunity.


Nutrition and the immune system

Diet has both direct and indirect effects on immunity. Overeating, ie obesity leads to already known health outcomes such as heart disease, diabetes and the like. However, an area that has received limited attention is the impact of obesity on the defense mechanism and the risk of infection. However, excess nutrient intake is thought to cause immune dysregulation, with obesity being associated with a low level of chronic inflammation and a higher risk of developing infections, especially those of the respiratory tract. Hence, increased physical activity can be beneficial for obese people to lose weight, but also because of the anti-inflammatory effects of exercise.

Malnutrition is characterized by insufficient intake of total energy and macronutrients and / or deficiencies in specific micronutrients. Malnutrition is one of the leading causes of immunodeficiency in developing countries. Although malnutrition is rare in developed countries, deficiencies in certain nutrients can occur simply as a result of poor dietary choices. Hence, it seems that one of the most pragmatic “interventions” (and perhaps the simplest strategy) to improve immunity and reduce the risk of infection is to eat healthy and balanced foods.


There are many factors that can affect immunity and the risk of infection. Regular physical activity and eating habits are important factors that have a significant impact on how well the immune system responds to each challenge. Therefore, despite being at home, eat in moderation and practice physical activity.