It is estimated that 17% of Americans will, at some point in their life, suffer from major depression, which is just one of several types of depression.

Many people afflicted with depression may not even know what they are suffering from. Often depressed people are only aware that they are tired and fatigued, aren’t sleeping well, or no longer have a zest for life.

Depression may masquerade as various physical illnesses. That is, often depressed people experience vague physical symptoms. In such cases, typically their physician does numerous tests but "can’t find anything wrong," and ends up treating them for depression. Conversely, there are physical illnesses that can cause depression, for example, hypothyroidism. And then there are some in-between conditions, such as chronic fatigue syndrome and various chronic pain syndromes such as fibromyalgia and migraine headaches. Some physicians believe that these conditions are fundamentally psychiatric in nature, while others believe that they are primarily physical illnesses. In either case, they often benefit from medication designed for depression.

Although depression is considered a mental illness and is treated with psychiatric medications, these medications do not cure the problem in the same way that antibiotics cure pneumonia by killing the bacteria that cause pneumonia. They do not even get at the root cause of depression, as, for example, insulin gets close to the root cause of diabetes by replacing the insulin that the pancreas can no longer manufacture. After all, people don’t suffer from depression because they are born with low blood Prozac levels

Exercise is Good for Depression

Exercise can indeed boost people's moods, but they may have to start off down in the dumps to feel the effects.

Researchers found that an hour of aerobics reduced tension, anger and fatigue among their study participants, with the benefit being significantly greater among those who felt depressed before the exercise bout.

A number of studies have shown that exercise can lift a person's spirits, and there is even evidence that physical activity can aid in treating clinical depression. The current study focused on "depressed mood," rather than clinical depression.

Research demonstrates that different types and intensities of exercise have varying effects on individuals' moods. The researchers studied 80 young men and women who volunteered to take mood tests just before and after an hour-long aerobics class.

The investigators determined that 52 volunteers were in depressed moods before the exercise, while 28 were not.

After exercise, the depressed-mood group was significantly more likely to report a reduction in anger, fatigue and tension, as well as increased vigor.

At least in the context of an aerobics class, merely getting through the activity may give a lift to a person who is feeling down.

Journal of Sports Medicine and Physical Fitness December 2001;41:539-545