The medical community generally views fatigue as a source of mystery --- a complex physical condition that afflicts millions of people worldwide. It is not quite on the same level as being tired, as most people can easily say that they are “beyond tired” by the time fatigue sets in. Fatigue sets the body into a state of near-total lethargy. When fatigue sets in, the continuation of other physical activities is almost always nearly impossible. Further activity could result in muscle spasms and pain in various parts of the body. Lower back pain is one of the most common ailments suffered by people with fatigue. In some cases, a fatigued individual may experience somnolence due to fatigue, though excessive physical labor is not the only cause of somnolence.
It is also possible for a person to experience a sort of “mental” fatigue that, in most respects, is not linked to the overexertion of the body. The mind is just like any other muscle of the body which requires periodic rest. Typically, mental fatigue sets in when someone experiences a rapid decline in mental functions including the reduction of analytical skills and creative thought. In rare cases, the ability to speak and write coherently is temporarily lost due to mental fatigue. For some, mental fatigue can be equated to a case of writer's block, essentially making the person willing yet unable to come up with creative ideas because of the excessive stress on the mind.
The problem is that, unlike physical fatigue, mental fatigue is not the sort of problem that goes away by taking a nice nap or having a good night's sleep. Mental fatigue is a continuous problem, one that leaves a person feeling drained of all intellectual and creative energies, with no definite treatment or solution to the problem it presents. It is a difficult condition to treat because of the various differences in psychology between person to person. One has to consider the great variations in the biochemistry of different people.
A method for helping alleviate mental fatigue that works for one person may not work for another person. Some find it helpful to re-focus their thoughts from one project to another, preferably one with a different creative style or design tone. However, for some people, this method merely taxes the “creative juices” further, aggravating the problem. For other people, a working method is to shift the focus of their mental energies into a project that is less strict, one that allows for more flexibility in achieving the objective. This usually works, but the approach carries with it the risk of long-term lack of focus on the project that had caused the mental fatigue, which proves to be a problem when that project is business-related and needs to be accomplished by a certain date.
In most cases, it is advised that people with mental fatigue should exercise, as this will get more oxygen flowing into the brain. Aside from that, most methods to relieve the problem are best found individually, as what works for one might not work for another. For most people, relaxing or shifting attentions to something less mentally taxing might be a good idea, but it might not work for some. It is generally best for a person to simply stop worrying over something and find a way of dealing with the problem that works for them.