For many, the transitional time between summer and fall triggers bouts of illness.  This experience is often intensified for those with a sluggish immune system.

Immune System
In general, the immune system protects us from foreign substances in the body.  It can accomplish this great task because of the special mechanisms in place that destroy these substances before they can multiply and cause illness.  When a person does get sick, it is because their resistance is lower than usual resulting in a greater chance of getting ill.  This is why a room full of people exposed to illness will not all get sick.
   
Immune Fighting Cells
Located throughout our body tissues are one of several types of immune fighting cells called macrophages (large eating cell), and they are designed to seek out and destroy by engulfing any foreign invaders in its path.

B-lymphocytes are stimulated when a specific targeted microorganism has entered the body.
Eosinophils, target histamine-producing substances (often causing allergic reactions), while specific white blood cells produce an inflammatory-response to prevent foreign invaders from spreading.   

Unfortunately, as you well may know, there are many times when our immune system is overwhelmed by illness and we get sick.  Often this is due to susceptibility and reduced resistance.
   
Susceptibility
Susceptibility refers to the inability to resist an illness-causing agent.  It could be due to an increased sensitivity as is often observed in individuals (not current on their vaccinations) who get sick when exposed to the antigen.

Resistance
The other side of susceptibility is resistance, which is the immune system’s capacity to destroy the agent.  Building resistance entails eating right, exercise, managing stress, and adequate sleep. 

Sleep
During periods of sleep, the body is fast at work repairing, regenerating, and replenishing itself.  Therefore, adequate sleep is a critical component of a healthy immune system, as sleep-deprivation increases susceptibility. 

During the summer, we tend to be more active; and with increased activity come fatigue, and a need to rest making adequate sleep easier to achieve.

During the cooler months when many of us are homebound, outdoor activities are significantly reduced; especially in some of the Northern states where the days are shorter and colder.
   
Fuel   
To function properly, the immune system requires a constant source of fuel (food).   I recommend food choices that are close to, as Mother Nature intended, not processed or refined.  You will feel better, stronger, and more alert if meals are smaller and eaten in a frequency, no greater than every three to four hours.

In conclusion, many people have a tendency to get ill during the transition between summer and fall.  Taking steps to boost your immunity, especially during this time will decrease your risk of getting sick.