used to take the basal (base) body temperature, the temperature upon waking. Basal body temperature is much less affected than daytime temperature by environmental factors such as exercise and food intake. This allows small changes in body temperature to be detected Glass oral thermometers typically have markings every 0.1 °C or 0.2 °F. Basal temperature is stable enough to require accuracy of at least 0.05 °C or 0.1 °F, so special glass basal thermometers are distinct from glass oral thermometers. Digital thermometers which have sufficient resolution (0.05 °C or 0.1 °F is sufficient) may be suitable for monitoring basal body temperatures; the specification should be checked to ensure absolute accuracy, and thermometers (like most digital instruments) should be calibrated at specified intervals. If only the variation of basal temperature is required, absolute accuracy is not so important so long as the readings do not have large variability (e.g., if real temperature varies from 37.00 °C to 37.28 °C, a thermometer which inaccurately but consistently reads a change from 37.17 °C to 37.45 °C will indicate the magnitude of the change). Some digital thermometers are marketed as "basal thermometers" and have extra features such as a larger display, expanded memory functions, or beeping to confirm the thermometer is placed properly. Smart and wearable thermometers A smart thermometer is able to transmit its readings so that they can be collected, stored and analysed. Wearable thermometers can provide continuous measurement but it is difficult to measure core body temperature in this way. See also Thermometer Liquid crystal thermometer Footnotes References Allbutt, T.C., "Medical Thermometry", British and Foreign Medico-Chirurgical Review, Vol.45, No.90, (April 1870), pp.429-441; Vo.46, No.91, (July 1870), pp.144-156. Medical testing equipment Thermometers Italian inventions