An overnight fast of 8-10 h is normal for most people. Fasting is characterised by a coordinated set of metabolic changes designed to spare carbohydrate and increase reliance on fat as a substrate for energy supply. As well as sparing the limited endogenous carbohydrate, and increased rate of gluconeogenesis from amino acids, glycerol and ketone bodies help maintain the supply of carbohydrate. Many individuals undergo periodic fasts for health, religious or cultural reasons. Ramadan fasting, involving 1 month of abstention from food and fluid intake during daylight hours, is practised by a large part of the world population. This period involves a shift in the pattern of intake from daytime to the hours of darkness. There seems to be little effect on overall daily dietary intake and only small metabolic effects, but there may be implications for both physical and cognitive function. The limited evidence suggests that effects of Ramadan-style fasting on exercise performance are generally small. This needs to be balanced, however, against the observation that small differences in performance are critical in determining the outcomes of sporting events. Studies involving challenging sporting events (prolonged sustained or intermittent high-intensity events, hot and humid environments) are needed. Increases in subjective sensations of fatigue may be the result of loss of sleep or disruption of normal sleep patterns. Modifications to the competition timetable may minimise or even eliminate any effect on performance in sport, but there may be negative effects on performance in some events.

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The aim of this study was to investigate the efficacy and safety of ondansetron as an augmentative agent to fluvoxamine in the treatment of patients with obsessive-compulsive disorder (OCD). Forty-six men and women, aged 18-60 years, who fulfilled the diagnostic criteria of OCD on the basis of the DSM-IV-TR and had a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score of at least 21 were recruited into the study. The patients randomly received either ondansetron (8 mg/day) or placebo for 8 weeks. All patients received fluvoxamine (100 mg/day) for the first 4 weeks, followed by 200 mg/day for the rest of the trial. The patients were assessed using the Y-BOCS and the adverse event checklists at baseline, and the second, fourth, sixth, and eighth week. Forty-four patients completed the study. The Y-BOCS total score as well as the Y-BOCS obsession subscale score and compulsion subscale score showed significantly greater reduction in the ondansetron group than in the placebo group. There was no significant difference in adverse events between the two groups. In this 8-week double-blind randomized-controlled trial, ondansetron showed significant beneficial effect as an augmentative agent with fluvoxamine in patients with moderate to severe OCD and it was generally well tolerated.