Effect of Metformin on Lactate Metabolism

Study design: Physiological study, controlled, open, non randomised Healthy male subjects, 18 to 30 years old Principal objective : To evaluate the influence of metformin on lactate metabolism (production) following exogenous lactate overload. * Objective 2: To evaluate the influence of metformin on lactate metabolism (production) after muscular exercise. * Objective 3: To evaluate the influence of metformin on lactate metabolism (elimination) after exogenous lactate overload. * Objective 4: To evaluate the influence of metformin on lactate metabolism (elimination) after muscular exercise. Principal outcome : Lactate production following exogenous lactate overload. * Outcome 2: Production of lactate following muscular exercise test. * Outcome 3 and 3': Parameters modelizing elimination of lactate following exogenous lactate overload (bi-exponential model). * Outcome 4 and 4': Parameters modelizing elimination of lactate following muscular exercise test (bi-exponential model). Inclusion criteria: * Healthy male subjects, 18 to 30 years * Body mass index (BMI) between 21 and 25 kg/m2 inclusive * Informed consent Exclusion criteria : * Ward of court or under guardianship (sheltered adults) * Adult unable to express their consent * Person deprived of freedom by judicial or administrative decision * Person hospitalised without their consent * Person under legal protection * Existence of a previously diagnosed pathology * Existence of a metabolic condition (obesity, diabetes) or a family history of such * Ongoing medical treatment.