Time-of-day effects on blood lactate levels following the Wingate anaerobic test in trained women athletes

This study aimed to examine the effect of time of day on anaerobic performance, blood lactate responses, and perceived exertion following the Wingate Anaerobic Test in trained women athletes engaged in regular resistance training. Twenty-one participants completed the test during three separate sessions conducted in the morning, afternoon, and evening. Ratings of perceived exertion were recorded immediately after exercise, while blood lactate concentrations were measured at baseline, 3 min post-exercise, and 33 min post-exercise to assess peak and recovery responses. The results demonstrated a significant effect of time of day on anaerobic performance, with peak and average power output significantly higher in the evening than in the morning (p < 0.01), and average power output also higher in the afternoon than in the morning. In contrast, fatigue index, blood lactate concentrations, and perceived exertion did not differ significantly across the different time points. These findings indicate that anaerobic power output varies with time of day, whereas fatigue index, blood lactate concentrations, and perceived exertion remain unaffected.