Basal body temperature is the lowest temperature attained by the body during rest (usually during sleep). It is generally measured immediately after awakening and before any physical activity has been undertaken.
In women, ovulation causes an increase of 0.2-0.4 degree Celsius in basal body temperature (BBT); monitoring of BBTs is one way of predicting the day of ovulation.
The tendency of a woman to have lower temperatures before ovulation, and higher temperatures afterwards, is known as a biphasic pattern.
For those who want to get / avoid pregnant, BBT enable her forecast her next ovulation date menstrual date.
BBT tells periodical change in her female hormone balance which is closely related to her physical condition (e.g. skin condition, metabolism) and mood.
Thus BBT implies valuable information to her fertility, healthcare and beauty.
2. Relation between BBT and female hormone balance
