The Relationship Between Dietary Intake and Meal Timing on Sleep Behaviors in Professional Male Rugby League Athletes.

PURPOSE: Sleep is important for athlete health and performance; however, the relationship between nutritional intake and sleep in elite male athletes is not well reported. This study described the relationship between dietary intake and sleep in male rugby league athletes. A secondary aim examined how evening dietary intake (≥6 PM), macronutrient and micronutrient composition, and dinner timing relates to sleep variables.

METHODS

Twenty-eight rugby league athletes had their dietary intake and sleep monitored for 7 consecutive days during preseason. Sleep (total sleep time [minutes], sleep efficiency [percentage], wake after sleep onset [minutes], and sleep onset latency [minutes]) was measured using actigraphy and sleep diaries. Dietary intake, including total daily and evening (>6 PM) energy, macronutrient, and micronutrient intake, was measured using a smartphone application (MealLogger and FoodWorks). Dietary data were paired with the corresponding nightly sleep outcomes to enable day-to-day associations between dietary intake and sleep behaviors. Furthermore, to investigate the influence of nutrient timing, all food and fluid intake consumed ≥6 PM was isolated and analyzed separately. Relationships between nutrient intake and sleep were assessed using linear mixed models.

RESULTS

Evening data showed for every 1 g and 1 g·kg-1 increase in sugar ≥6 PM, there was a significant decrease in sleep efficiency by -0.21% (P = .03) and -0.22% (P = .02), respectively. No other significant associations between intake or sleep outcomes were shown.

CONCLUSIONS

Evening (≥6 PM) sugar intake in professional male rugby league athletes is associated with poorer sleep efficiency. Future research should explore how the manipulation of dietary intake could guide dietary recommendations to improve sleep in rugby league athletes.