We know that stress can cause havoc but a study says that stress can actually be good for us.

Dhabhar is an associate professor of psychiatry and behavioral sciences and member of the Stanford University Institute for Immunity, Transplantation, and Infection.
The immune system, as we know, is crucial for fighting or preventing infections and for healing wounds both of which occur commonly during chases, escapes, combat and other risky times.
Dhabhar collaborated with his colleagues at Stanford and two other universities to demonstrate this fact. Their work showed that subjecting lab rats to mild stress created a massive influx of several types of immune cells into the bloodstream and, later on, onto the skin and other tissues.
“This large-scale migration of immune cells, which took place in over two hours, was comparable to the mustering of troops in a crisis”, Dhabhar said.
Investigators demonstrated that the huge redistribution of immune cells all over the body was brought about by three hormones that were released by the adrenal glands in different amounts and at different times, in response to a stressful event. These findings tell us how the mind influences our immune responses.
Stress is of two types acute and chronic. Acute stress has a short term duration and is common in every day life. It is the type of stress that is cited as beneficial. Chronic stress on the other hand, is extremely detrimental for one’s well being and needs to be appropriately managed.
Reference:
1. http://shine.yahoo.com/healthy-living/the-surprising-benefits-of-stress-1285344.html
Source-Medindia