Aspirin intake in the morning is associated with suboptimal platelet inhibition, as measured by serum Thromboxane B during infarct-prone early-morning hours.

Aspirin is traditionally taken once daily in the morning and considered to be effective throughout the 24h interval. Cardiovascular events occur most frequently in the early morning, suggesting that these hours are critical in terms of adequate platelet inhibition. This study therefore assed platelet function in the early morning-8.