Myokines and Resistance Training: A Narrative Review.

In the last few years, the muscular system has gained attention due to the discovery of the muscle-secretome and its high potency for retaining or regaining health. These cytokines, described as myokines, released by the working muscle, are involved in anti-inflammatory, metabolic and immunological processes. These are able to influence human health in a positive way and are a target of research in metabolic diseases, cancer, neurological diseases, and other non-communicable diseases. Therefore, different types of exercise training were investigated in the last few years to find associations between exercise, myokines and their effects on human health. Particularly, resistance training turned out to be a powerful stimulus to enhance myokine release. As there are different types of resistance training, different myokines are stimulated, depending on the mode of training. This narrative review gives an overview about resistance training and how it can be utilized to stimulate myokine production in order to gain a certain health effect. Finally, the question of why resistance training is an important key regulator in human health will be discussed.

Metabolomic, hormonal and physiological responses to hypoglycemia versus euglycemia during exercise in adults with type 1 diabetes.

INTRODUCTION: This study sought to compare the metabolomic, hormonal and physiological responses to hypoglycemia versus euglycemia during exercise in adults with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Thirteen individuals with T1D (hemoglobin; 7.0%±1.3% (52.6±13.9 mmol/mol), age; 36±15 years, duration diabetes; 15±12 years) performed a maximum of 45 min submaximal exercise (60%±6% V̇O2max). Retrospectively identified exercise sessions that ended in hypoglycemia ((HypoEx) blood glucose (BG)≤3.9 mmol/L) were compared against a participant-matched euglycemic condition ((EuEx) BG≥4.0, BG≤10.0 mmol/L). Samples were compared for detailed physiological and hormonal parameters as well as metabolically profiled via large scale targeted ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. Data were assessed using univariate and multivariate analysis techniques with false discovery rate adjustment. Significant results were considered at p≤0.05. RESULTS: Cardiorespiratory and counterregulatory hormone responses, whole-body fuel use and perception of fatigue during exercise were similar under conditions of hypoglycemia and euglycemia (BG 3.5±0.3 vs 5.8±1.1 mmol/L, respectively p<0.001). HypoEx was associated with greater adenosine salvage pathway activity (5'-methylthioadenosine, p=0.023 and higher cysteine and methionine metabolism), increased utilization of glucogenic amino acids (glutamine, p=0.021, alanine, aspartate and glutamate metabolism and homoserine/threonine, p=0.045) and evidence of enhanced ß-oxidation (lower carnitine p<0.001, higher long-chain acylcarnitines). CONCLUSIONS: Exposure to acute hypoglycemia during exercise potentiates alterations in subclinical indices of metabolic stress at the level of the metabolome. However, the physiological responses induced by dynamic physical exercise may mask the symptomatic recognition of mild hypoglycemia during exercise in people with T1D, a potential clinical safety concern that reinforces the need for diligent glucose management. TRIAL REGISTRATION NUMBER: DRKS00013509.