It's as inevitable and, in most cases, as unwelcome as that overcrowded rush-hour train. Stress: We're all its victims to some degree. But do we know what causes it, and what its long-term effects on the body can be?
At its most basic level, human stress is emotional change, or the impairment of homeostasis that may result from interaction with the environment. In other words, stress is tension -- whether physical or mental -- brought about by external factors. Physical factors can include the likes of exposure to extreme temperatures, injury or shock; psychological ones can range from marital breakdown to stage fright.
But not all stress is bad. Exercise produces temporary physical stress, but its benefits are undeniable -- unless you have an undiscovered heart condition. Occasional stress can also be useful and productive if we have a way of channeling the energy it creates.