Integral Physiological Adaptations to Carbohydrate Periodization (IPACP)

The purpose of this study is to examine the effect of long-term carbohydrate periodization protocols on sleep architecture, sleep quality, daytime sleepiness, physical performance, body composition, gut microbiome, and miRNA in healthy trained individuals.

Athletic populations have been particularly susceptible to sleep inadequacies, experience several sleep issues, and fall below the age-specific sleep recommendations. However, it is well demonstrated that exercise does not impair sleep by itself, and furthermore, acute post-exercise nutrition could elevate the exercise-induced sleep-optimizing effect, with further benefits for the next physical performance. In line with these findings, in a metanalysis of clinical trials, it was shown that pre-bed carbohydrate availability resulted in significant alterations in sleep architecture. It is of utmost importance to highlight that throughout this metanalysis, it was revealed that no long-term nutrition intervention for sleep optimization has been studied yet. These data raise the question of whether a long-term carbohydrate periodization protocol could optimize sleep and alter gut function in a way that athletic performance will be also enhanced. This would allow elucidating further potential interrelations and biological pathways underlying these adaptations.

sleep, Carbohydrate periodization, Dietary Intervention, Sports Nutrition, Chrononutrition, Chronobiology, Gut Microbiome, miRNA

This is a randomized controlled trial. The study is composed of three groups, differentiating on evening carbohydrate quantity and quality (glycaemic index) intake. The trial period will last for 1 month for all groups. Intervention includes lifestyle changes, targeting exercise, and diet. The design is parallel.

Parameters such as questionnaires' scores, polysomnography outcomes, indices of health, gut microbiome, miRNA and other data will be masked and coded for blind analysis by the main investigator.

Dietary Intervention: Consumption of Low Glyceamic Index (LGI) carbohydrates intake post-workout/evening.

Dietary Intervention: Consumption of High Glyceamic Index (HGI) carbohydrates intake post-workout/evening.

Changes sleep efficiency assessed by the gold-standard method of polysomnography. Sleep efficiency is the percentage of time spent asleep while in bed. It is calculated by dividing the amount of time spent asleep (in minutes) by the total amount of time in bed (in minutes). A normal sleep efficiency is considered to be 85% or higher.

Changes in Quality of Sleep will be assessed by the Pittsburgh Sleep Quality Index. The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire that assesses sleep quality over a 1-month time interval. The measure consists of 19 individual items, creating 7 components that produce one global score. The sleep component scores are summed to yield a total score ranging from 0 to 21 with the higher total score (referred to as the global score) indicating worse sleep quality.

Changes in Daytime sleepiness will be assessed by Epworth Sleepiness Scale (ESS). The Epworth Sleepiness Scale (ESS) measures the general level of daytime sleepiness. It is a subjective scale that asks the respondent to rate his or her propensity to doze or fall asleep during 8 common daily activities to determine the level of daytime sleepiness. The score varies between 0-24 with 0-5 Lower Normal Daytime Sleepiness, 6-10 Higher Normal Daytime Sleepiness, 11-12 Mild Excessive Daytime Sleepiness, 13-15 Moderate Excessive Daytime Sleepiness, 16-24 Severe Excessive Daytime Sleepiness.

Changes in Body composition. The changes in body composition will be assessed by the skinfold measurements and BIA

Changes in Exercise Performance will be assessed by a VO2max test. A VO2 max test is a maximal exercise test performed on a treadmill or bike while connected to a machine capable of analyzing your expired air. Your test provides data on how much oxygen you use as you exercise and determines the maximal oxygen you can consume during exercise.

Changes in Gut Microbiome. Participants' gut microbiome will be studied by analyzing stool samples DNA will be extracted, and the presence of selected gut bacterial populations will be examined qualitatively and quantitatively using specific primers and quantitative Real-Time PCR.

Changes in miRNA levels. miRNA levels that are associated with hypertrophy or cardiovascular function will be analyzed by blood sample collection at baseline and at one month.

Inclusion Criteria: Both sexes, Age between 18 and 50 yrs old, Regularly participating in sports activities. Exclusion Criteria: Any kind of history of major diseases or medication, Excessive amounts of alcohol and caffeine consumption