The real causes of fatigue are still unknown, but doctors and scientists know what factors usually precede them. Read on to understand these factors so that you can find ways to avoid them.

Life changes. Life-altering events can cause mental and physical fatigue. Among the many fatigue-inducing events, divorce is still takes the lead. Divorce causes a lot of stress, and when it is not eliminated, can eventually lead to chronic fatigue.

Other life changes that cause fatigue are bereavement and grief for a lost loved one, unemployment and job instability, a serious illness, working with unreasonable employers, and many others. Studies find more and more people are worried about money, causing them to feel constant pressure and stress -leading to chronic fatigue. Some people are also born 'natural worriers,' which causes constant fatigue.

Substances. Some substances may also cause fatigue. Alcohol and the artificial sweetener called 'aspartame' are just two of the many culprits.

Hormonal imbalances. The cause of fatigue for women may be hormonal imbalances, according to recent studies. In fact, fatigue is one of the most common symptoms of hormonal imbalance, and 80 percent of women in their perimenopause and menopause stages are fatigued. The hormonal imbalances cause women to have sudden hot flashes, and night sweats leading to disrupted sleep that leads to fatigue.

Diet and stress add to the adrenal insufficiency experienced by women at this age. This, in turn, affects the thyroid function and melatonin production. Some women tend to be 'yo-yo' dieters, or have very unhealthy eating habits, which causes them to suffer from insulin resistance and low metabolism. These factors inevitably lead to fatigue as well.