Monitoring the effect of alcohol intake via facial temperature variations using thermography synchronized with heartbeat.

Accurate assessment of alcohol-induced physiological effects is critical for preventing overconsumption and ensuring safe activities such as driving. While breath alcohol concentration (BrAC) measurement is widely used due to its simplicity, it can be confounded by mouth alcohol effects and provides only momentary data. Building on our previously developed Synchro-thermography technique, which synchronizes infrared thermal imaging with heart rate variability to detect vascular-related skin temperature fluctuations, we applied it to monitor physiological changes induced by alcohol. In an alcohol intervention experiment, we observed that under non-drinking conditions, facial temperature fluctuations strongly synchronized with heartbeats. In contrast, following alcohol consumption, this synchrony markedly weakened within 10-30 minutes, regardless of the presence or absence of flushing responses. These results suggest that dynamic monitoring of temperature-heart rate synchrony offers a sensitive, non-contact indicator of early alcohol effects. Although preliminary, our findings highlight the potential of Synchro-thermography as a practical tool for non-invasive, real-time monitoring of alcohol-induced physiological changes.