Probiotic Supplementation Can Alter Inflammation Parameters and Self-Reported Sleep After a Marathon: A Randomized, Double-Blind, Placebo-Controlled Study

<b>Background:</b> Sleep is essential for athletes' physical performance and recovery. However, strenuous exercise has the potential to increase inflammation and worsen sleep. This study evaluated the effect of probiotic supplementation on self-reported sleep quality, daytime sleepiness, and inflammatory profile 24 h after a marathon. <b>Methods</b>: 27 marathon male runners were divided into the Probiotic group (Probiotic n = 14) or the Placebo group (Placebo n = 13). The Probiotic group consumed 1 × 10¹⁰ CFU of Lactobacillus acidophilus, 1 × 10¹⁰ CFU of Bifidobacterium lactis + 5 g/day maltodextrin for 30 days prior to the marathon. The Placebo group received a sachet of 5 g/day maltodextrin during the same period. Sleep and inflammatory status were assessed before supplementation, before the marathon, and 1 h and 24 h after the marathon. Data were analyzed using Statistic 13.3 and expressed as mean ± standard deviation. Tukey's post hoc test was followed by a two-way ANOVA with repeated measures. The level of significance was set at <i>p</i> ≤ 0.05. <b>Results</b>: In the Placebo group, daytime sleepiness, sleep latency, and global sleep score increased 24 h after the marathon, while total sleep time and sleep efficiency decreased. In the Probiotic group, daytime sleepiness, sleep latency, and global sleep scores were lower 24 h after the marathon compared to the Placebo group. Total sleep time and sleep efficiency were higher in the Probiotic group compared to the Placebo group 24 h after the marathon. IL-1β and TNF-α concentrations decreased compared to Basal in both groups. IL-1β levels were lower 24 h after treatment compared to pre-treatment in the Placebo group. IL-6 was lower 24 h after the marathon in both groups. LPS concentrations were lower 1 h and 24 h after the marathon in the Probiotic group compared to the Basal group. There was no difference in cytokines and LPS between the groups. <b>Conclusions</b>: Supplementation with <i>Lactobacillus acidophilus</i> and <i>Bifidobacterium lactis</i> for 30 days changes self-reported sleep and reduces LPS concentration after the marathon.