An Investigation into the Effects of a 12-week Sleep Low Train Low Intervention on Fat Oxidation and Exercise Performance in Recreationally Endurance-Trained Women

Background: Combining training stimuli with nutritional interventions to maximise the training effect has become the topic of numerous research studies and reviews. The Sleep Low Train Low (SLTL) protocol has become popular amongst endurance athletes as a method of increasing fat oxidation and thereby reduce glycogen dependence in events in excess of 90 minutes. The SLTL protocol was adopted for this study. Purpose: It was hypothesised that implementing a 12-week SLTL protocol would increase fat oxidation and beta-hydroxybutyrate (BHB) production during exercise without negatively effecting performance. Methods: 25 women who are endurance trained were recruited. 21 women (mean age 41.9 years +/- 7 years) completed the 12-week training intervention. 12 incorporated a sleep low train low element, while 9 were pre-fuelled for all sessions (pre & post testing consisted of a FATMAX/VO2 max test, 20-minute functional threshold power test & 90 minute endurance power test on a bike ergometer). Menstrual cycle (MC) phase and function where appropriate were established, tracked and accounted for using questionnaires/test data sheets and morning oral temperature. Results: Analysis highlighted a significant increase in mean peak fat oxidation (PFO in g/min) (p