Exploring the Relationship Between the Gut Microbiome, Physical Fitness Levels and Metabolic Responses to Exercise
Condition: Elite Cyclists; Elite Soccer Players; Sedentary Behavior
Study type: Observational

Summary: 
      Gut microbiota are all microorganisms including bacteria and microscopic eukaryotes that live
      in the digestive tracts of humans or mammals. During the last decade, some authors
      highlighted that a link exists between gut microbiota and sport performance. In this project,
      we hypothesize that gut microbiota is able to adapt to the energy needs of the body, really
      higher in top-level athletes or considerably lower in inactive individuals. In this context,
      this clinical study aims to characterize the bacterial metagenome of gut microbiota from
      populations located in a continuum from sedentary people to top-level athletes with high
      (i.e. soccer players), even very high energy needs (i.e. cyclists). The finality of this
      project is thus to determine if it exists some bacterial profile allowing to characterize,
      even to predict, the energy metabolism of an athlete and so the probability to be performant
      in competition.
    

Detailed description: 
      Gut microbiota are all microorganisms including bacteria, archaea and microscopic eukaryotes
      that live in the digestive tracts of humans or mammals. All these microorganisms live in
      homeostasis in the gastrointestinal tract and provide a variety of benefits to the host
      immune system and energy metabolism in a state called eubiosis. On contrary, a state of
      dysbiosis occurs when the diversity of commensal bacteria is reduced especially in some
      chronic diseases including obesity, cancer or gastrointestinal diseases. During the last
      decade, substantial studies highlighted that a link exists between gut microbiota composition
      and sport performance. Research team especially identified a direct link between gut
      microbiota and skeletal muscle, a key organ in sport performance (Nay et al. 2019). Using
      rodent models, They observed that 1) the endurance performance was reduced in mice for which
      the gut microbiome had been experimentally destructed (Nay et al. 2019), and 2) the reduction
      of endurance performance was due to lower muscle glycogen levels, a key energy substrate for
      muscle endurance.

      Complementary researches have been conducted in humans to characterize the impact of physical
      activity on gut microbiota composition and function. A study conducted in large American
      cohort of 1500 individuals have thus highlighted that the gut microbiota diversity was much
      more important in individuals performing regular physical activity (3-5 times/week or more)
      compared to physically inactive people. The few studies conducted in top-level athletes are
      in accordance with these results. Indeed, it has been demonstrated that international Irish
      rugby players exhibited a clear higher microbial diversity than inactive and sedentary
      populations associated to higher production of short-chain fatty acids (SCFA), some key
      energy substrates produced by commensal bacteria (Clarke et al. 2014; Barton et al. 2018).
      Conversely, when people are completely physically deconditioned such as astronauts under
      microgravity or bedridden patients, a clear modification of gut microbiota composition occurs
      in the gastrointestinal tract (Voorhies and al. 2019). Such differences between top-level
      athletes, inactive or extremely inactive individuals cannot be only explained to lifestyle,
      especially diet. Indeed, longitudinal studies have clearly showed that a several weeks
      training period can increase the gut microbial diversity in humans suggesting an increased
      capacity of gut microbiota to extract energy from food, especially from dietary fibers (Allen
      et al. 2018). All together, these data support that the gut microbiota could adapt to the
      energy needs of the body, really higher in top-level athletes or considerably lower in
      extremely inactive individuals (e.g. astronauts or bedridden patients). These data also
      suggest that gut microbiota could punctually inform of the body's metabolic state of an
      individual.

      In this context, this clinical study aims to characterize the bacterial metagenome of gut
      microbiota from populations located in a continuum from sedentary people to top-level
      athletes with high (i.e. soccer players), even very high energy needs (i.e. cyclists). The
      finality of this project is thus to determine if it exists some bacterial profile allowing to
      characterize, even to predict, the energy metabolism of an athlete and so the probability to
      be performant in competition.

      For this purpose, we will assess the metabolic responses to exercise from different athletic
      populations (i.e. elite cyclists and soccer players) and non-active of moderately active
      populations. All the volunteers (n=50) will perform 3 visits in the M2S lab: 1) an inclusion
      visit including anthropometric measures, dietary and physical activity surveys, and after
      which the volunteer will leave the lab with a Nahibu kit allowing to send us a fecal sample
      in the next 7 days, 2) a second visit to perform the incremental cycling test, 3) a last
      visit to perform metabolic measures in fasted condition in basal and during submaximal
      exercises. The metabolic parameters measured during these tests (e.g. VO2max, power in
      aerobic and anaerobic thresholds, maximal carbohydrates and lipids oxidation) will be then
      related to the metagenomic shotgun data obtained in fecal samples.
    

Intervention name(s): Maximal incremental exercise test; Submaximal exercise test
Intervention type(s): Diagnostic Test; Diagnostic Test
Intervention description(s): Gas exchanges are measured during all the test on ergocycle until oxygen consumption reach its maximum value; A 25-min submaximal exercise test on ergocycle under fasting condition. Gas exchanges are measured during all the test.
Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Populations located in a continuum from inactive people to top-level athletes with high
        (i.e. soccer players) and very high energy needs (i.e. cyclists).
      
Biospecimen description: 
      Frozen stool suspension
    
Keywords: Physical activity; Carbohydrates and lipid metabolisms; Gut microbiota; Maximal oxygen consumption