There are three main biorhythm cycles: physical, emotional and intellectual. Each cycle starts with birthdate (all values equl to zero).

Basically biorhythm is a sinusoidial curve (wave). Each biorhythm has it's own cycle: physical 23 days, emotional 28 days, intellectual 33 days. It will take approximately 58 years (biorhythmic span) for biorhythms to come to initial point. New life starts at 58 afterall!

Physical Biorhythm (23 days)

Cycle are thought to influence strength, endurance, energy, and general physical well-being.

We all have experienced days when energy seems to be very low. And after some time this energy seems to go up. Biorhythm theory suggests that we can predict those ups and downs with physical biorhythm.

During the positive side of the cycle (2-11 days) physical condition is in a charged state. So Physical work is easier, we have more vitality and endurance. It might happen that physical force is overly strong resuling in susceptibility to reckless, aggressvie activities.

During negative portion of cycle (13-23 days) we are in recharghing state. Vitality is at the low end of the tide. So we might tire more easily, experience fatique and drained. "Worn-out" feeling is expected during this period. This is good time for relaxation ar rest.

Emotional Biorhythm (28 days)

During the high end person might feel more optimism and cheerfulnes also creativity, feelings, love and cooperation.You will be able to enjoy others, and share support, encouragement and empathy. It is good time to stregthen relationships.

During the low end of the cycle emotions are in a recover state. Irritation and negative feelings are expected.

Since the emotional cycle is 28 days long, exactly 4 weeks, day 1 and day 15 always fall on the day of the week that you were born.

It is worth mentioning that biorhythms affect each person individually and is closely related to person's temperament. So ups and downs may be more noticable on extravert people, etc.

Intelectual Biorhythm (33 days)

During first half of cycle (positive) one is more capable of absorbing new ideas and can think more clearly. Mental responses are more spontaneous and memory functions better.

This is a good time for creative thought, studying new ideas, decision making. Absorbing new concepts is easier and notable progress can be achieved.

During negative cycle ability to think logically is somewhat reduced. Judgments and concentration on tasks may be frustrating. During this time mind wants a rest in order to recover and store up energy again. It gets more difficult to absorb new ideas and perform mental exercises.

This time is best suited to review previously learned concepts and completing other postponed tasks not requireing intesive intellectual effort. These may be days when important decisions could best be delayed.

Critical Days

Critical day is the time when biorhythm corsses 0 line. Line will go from positive to negative area or vice versa.

This transition will take approximately 1-2 days. Person in critical zone should be careful because of increases vulnerability. Critical lines become more significant if two or three lines are in critical zone at the same time.