An infrared thermography based technique is described for monitoring an individual's thermoregulation performance and thermal comfort level through measuring the skin temperature on several points the face as the face has a high density of blood vessels and it is typically not covered by clothing. This technique allows for continuous monitoring during normal daily activities and instantaneous identification of thermoregulation performance and thermal comfort. The vascular territories in addition to vasodilation and vasoconstriction of the blood vessels can be used to estimate personal thermal comfort levels. Systems for implementing the technique are described, and can include one or more infrared sensors implemented on glasses for detecting temperature. Data from the sensors is processed by a suitable processor and memory. The processor can continuously monitor the person's blood vessels shrinking and widening which represents thermoregulation performance. Uncomfortable/harmful conditions can be detected by monitoring trends in measurements before the conditions actually occur.
