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Causes of a Weak Immune System

Your immune system is one of the most important systems in your body, since it is constantly working to prevent dangerous or life-threatening diseases from overtaking your body. Some people naturally have a stronger immune system than others. However, there are also many things you could be doing that are weakening an adequately strong immune system and causing you to become sick more often than you should. Here are some of the most common causes of a weak immune system.


“Good” prostaglandins are localized hormones in your body that support the function of your immune system. However, when you are under periods of great stress, this can raise the cortisol levels in your body, which decreases the production of good prostaglandins in your body. Therefore, chronic stress weakens your immune system and makes you more susceptible to contracting the common cold or the flu, as well as more serious problems such as heart disease and diabetes.

Poor Diet

If you are excessively consuming refined sugars and highly processed foods that contain pesticides, chemical additives, and preservatives over a long period of time, this can also lead to a weakened immune system. Recent research shows that after consuming 100 grams of sugar (approximately three cans of soda), your white blood cells’ ability to kill bacteria is significantly hampered for up to five hours.

Excessive Alcohol Consumption

Similarly to sugar, consuming large amounts of alcohol in one sitting can reduce the ability of your white blood cells to kill germs. In the short term, consuming more than two drinks in one sitting will make you more susceptible to becoming sick with viruses such as the common cold. However, in the long term, excessive alcohol consumption can permanently impede the functioning of your immune system cells, which will increase your risk for more serious diseases such as cancer.

Lack of Sleep

If you are not getting enough sleep each night, your body is not well-rested. This means that your immune system is not getting the chance to rebuild each night, which can cause it to become weaker. Poor sleep is also associated with a reduced number of T cells, which are specialized white blood cells that help your body to fight off infectious diseases.

Lack of Physical Activity

Getting at least 20 to 30 minutes of moderate physical activity each day improves your blood circulation, which promotes the movement of antibodies and white blood cells that are essential for fighting off infections. Research shows that inactive people are sick twice as often as people who are physically active almost every day.

Lack of Personal Hygiene

If you do not practice good hygiene habits, this exposes your body to more germs, which makes your immune system more susceptible to infection. This includes brushing your teeth twice a day, washing your hands before eating, and keeping your nails short and clean.

Last Updated: November 23, 2015