The impact of a «symptomless hangover» on a personʼs reaction speed

Background. While a blood alcohol concentration above 0.2 g/L is legally defined as an aggravating factor impairing attention, the influence of alcohol metabolites after complete ethanol elimination–when clinical signs of intoxication are absent–remains insufficiently studied in forensic medicine. Purpose – to study the impact of subclinical alcohol intoxication consequences on human cognitive functions. Materials and Methods. Forty-two healthy volunteers were examined. Reaction time was evaluated using a sensorimotor test (button press in response to a color change) and Schulte tables. Testing was performed in a sober state and at 15, 30, 60, 90, and 120 minutes after sobriety. Statistical analysis was performed using the McNemar test. Results. Analysis of the sensorimotor experiment showed a statistically significant slowing of reaction time compared with baseline during the first 30 minutes after sobriety. At 15 minutes after alcohol elimination, the proportion of better responses decreased from 69.05% to 30.95%. At 30 minutes, the proportion of better performance was 26.19% compared with 73.81% in the sober state. Schulte table testing confirmed these findings, showing significant impairment at 15 and 30 minutes after sobriety. From 60 minutes onward, performance gradually stabilized, with no statistically significant difference from baseline. However, gender analysis revealed differences at 60 minutes: women showed a higher response rate (70%) than men (31.8%). The study confirmed that cognitive impairment persists for up to 1 hour despite zero breath alcohol and absence of hangover symptoms. Conclusions. Asymptomatic hangover negatively affects reaction time for up to 60 minutes after sobriety, with the greatest impairment within the first 30 minutes. Gender differences in recovery support a differentiated risk assessment. This effect should be considered a risk factor for drivers in regulatory frameworks.