Exclusion Criteria:1) History of acute or chronic illness that may hinder study procedures or confuse interpretation of the data (e.g. dermatological, neurological, psychiatric or addictive diseases) 2) Clinically significant cardiovascular, pulmonary, hepatic or renal diseases 3) Major bodily injury within 3 months of study participation 4) Surgery within 3 months of study participation 5) Pregnancy or breast-feeding 6) Intake of prescription drugs with anti/pro-inflammatory action 7) Intake of prescription drugs with anti/pro-analgesic action 8) Inability to abstain from any anti/pro inflammatory drugs during the 24-hour period preceding a study session 9) Inability to abstain from any anti/pro-analgesic drugs during the 24-hour period preceding a study session 10) Prior medical history that would contraindicate the use of NSAID, or previous negative reaction to NSAIDs or aspirin 11) Inability to obtain at least 6 hours of sleep during the night preceding a study session