Have you ever noticed that you tend to get sick more often when you're stressed out? Scientists have noticed this connection for a long time, but until recently they couldn't explain it. While a big project at work or the loss of a loved one isn't going to give you the flu, it can decrease the functioning of your immune system and make you more susceptible to the flu and other infections.

It may surprise you, but short term stress actually boosts the immune system. Increased immune functioning is associated with the "fight or flight" response related to short term stress you know will end. This is because our body is still trying to adapt to beat the stressor instead of just letting the stress bear down. The problem with this is that a majority of our stress is continual over a long period of time.

Long term stress is what actually decreases our immune functioning. The worst kind of stress is not only long term, but stress we think we can't control or see an end to. For example, while meeting a deadline at work may cause a decrease in our immune functioning; it's probably not as bad as stress caused by a debilitating accident. When we think the stressor is beyond our control and may never stop, our body feels it can't cope with the stress and it begins to take its toll. This kind of stress causes a drop in almost all immune functioning.

For regular, long term stressors, the decrease in immune functioning becomes greater with time. This means even if you feel you are in a position of control, long term stress such as a high power job, can build up and gradually decrease your disease fighting abilities.

Another important factor to consider when looking at the immune system and stress is that the decrease in immune system functioning is greater for people who are elderly or already sick. This is likely why older people who are severely injured or have recently lost a loved one are much more likely to die within a year than those who haven't had these circumstances.

You may think, "Well, I'll drop my stress level and I'll be fine". However, studies have show that traumatic events can stick with us and affect our immune system long after the stressor is gone. If a person was in an accident, was attacked, or experienced a traumatic loss, they can show decreased immunities years later. The best way to increase immunities in this case is to undergo treatment for the trauma.

In addition to causing a decrease in immune system functioning, stress can also make you more susceptible to other long term diseases, such as cardiovascular disease. If you want to maintain a healthy lifestyle you should include activities and a proper diet that promote a less stressful lifestyle.