Topic 13 - Exercise and immunity

• The immune system protects the body from infectious diseases and is involved in tissue repair and protection against potential pathogens.
• The Mechanisms used by the body in response to damage or infectious agents:

  • Physical: skin, epithelial linings, mucosal secretions
  • Chemical: pH of body fluids, hormones and other soluble factors
  • Leucocytes: (white blood cells) fight disease
  • Inflammation: body's response to tissue irritation, injury or infection alerts the body of an injury
  • Clotting: platelets trap RBV creating a blood clot to prevent bleeding
  • Lymphocyte and antibody production attack antigens
• Physical mechanisms in response to infectious agents:

  • Skin: provides a physical barrier to the entrance of bacteria
  • Epithelial linings: line the lung and gut containing cilia which reduce the entrance of foreign bodies
  • Mucosal secretions: trap bacteria and small particles
• Chemical mechanisms in response to infectious agents:

  • pH of body fluids help to destroy pathogens
  • tears and saliva wash away any microbes (bacteria causing infection)
  • stomach acid kills organisms
• Athletes are more susceptible to infections than their sedentary peers because of:

  • lower leucocyte numbers caused by stress of exercise
  • inflammation caused by muscle damage preventing blood flow
  • greater exposure to airborne bacteria and viruses because of increased rate and depth of breathing during exercise
• Moderate athletes:

  • better circulation, stronger hearts, healthier blood vessels
  • being moderately active boosts the efficiency of every system in the body
• Sedentary athletes:

  • increased susceptibility to infection compared to moderate athletes
  • have poorer circulation, preventing their ability to fight infection
• the relationship between exercise intensity and susceptibility to disease can be seen as a 'J curve' because an athlete must be physically fit and have an immune system which can withstand infections
• strategies to minimise risk from infection:

  • sufficient recovery time
  • avoid close contact with infectious people
  • maintain hydration status
  • maintain good personal hygiene
  • maintain a suitable and varied diet
  • ensure sufficient sleep