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Basal Thermometer vs Regular Thermometer

Thermometers are devices used to measure variations in the body temperature. There are two types - basal and regular, which are used in different ways.
Narayani Karthik
Thermometers are temperature measuring devices that give an accurate temperature gradient. Here we will be studying two types of these devices - Basal and regular. The normal thermometers are the ones that come handy when detecting anomalies (like fever) in the body. But a basal one comes with an additional purpose. Apart from detecting minor variations in body temperature, it is used for measuring ovulation in women, who want to know about the right time for conception and pregnancy.
The regular thermometer is a mercury filled instrument, consisting of a small mercury filled bulb attached with the tube. Below the bulb, there is a small constriction. So, whenever there is a temperature variation, the mercury inside it expands and tries to push itself through the constriction. When the temperature drops, the mercury remains stagnant inside the bulb. To reset the instrument back to normal, it has to be swung once or twice. The typical range of a regular thermometer is between 89.6ºF - 109.4ºF (35ºC - 42ºC). Usually, it is used for measuring temperature deviations in the body. However, they do not give any precision on basal body temperatures.
If a woman wants to conceive, it is essential for her to know about her body basal temperature during ovulation. This is where the basal thermometer helps! The major catch in the debate over usage of basal instruments is that, unlike normal regular ones, they measure body temperature by 10th of a degree. This instrument is quite sensitive and records even the minutest variation in the body temperature. Hence, the level of precision is any day high in these instruments. So, it is used for measuring ovulation in a woman.
Basal body temperature is one of the major signs of ovulation. The body temperature rises during this period, pertaining to hormonal changes in a woman. When a woman wants to determine her fertility period, she is advised to check for her basal body temperature, early in the morning and late in the evening, using basal thermometer. This procedure needs to be repeated almost daily and the temperature recordings should be maintained in a log book. These instruments can easily detect a rise of 0.4ºF -0.6ºF in the body temperatures. From these recordings, one can easily know whether the woman has pre-ovulation basal temperature (97.4ºF) or post-ovulation basal temperature (97.7ºF). These temperature recordings aid the woman in deciding her chances of getting pregnant during ovulation. From the temperature variations, even the right time for sexual intercourse can be decided to promote conception and pregnancy.
Nowadays, there are different kids of basal thermometers. Digital ones are also available, which come with a kit and a blank basal body temperature graph for use. Glass basal ones are also used, but are not as popular as the digital ones, as the latter have facility to store the temperature recordings.
  • A basal thermometer is more precise in measuring temperatures. This can measure the temperature variations by 10th of a degree, whereas normal ones measure temperature variations in 2/10th degree increments.
  • When it comes to reliability, basal ones are definitely more reliable than regular ones. Normal instruments show accuracy up to 0.2ºF, whereas basal ones show accuracy up to 0.1ºF.
  • The best feature of a basal device is its speed factor. It barely takes 30-60 seconds to detect a temperature variation. A digital one will even record the temperature for you, just in case you were not able to note it down.
Hence, basal instruments are better, as they record the lowest body temperature. Also, they helps a woman in understanding her ovulation cycles better before conceiving.