High-Intensity Exercise Causes Greater Irisin Response Compared with Low-Intensity Exercise under Similar Energy Consumption

Abstract

Irisin is mainly released from skeletal muscle (myocytes) and promotes thermogenesis by browning of the white adipose tissue. Although exercise has been shown to increase irisin concentration in blood and myocytes via up-regulation peroxisome proliferator receptor γ coactivator-1α (PGC-1α) expression, the influence of exercise intensity on irisin secretion remains unclear. Therefore, we determined circulating irisin responses following a single bout of running at different intensities. Six sedentary males underwent treadmill running under two different conditions: a low-intensity (40% of V 4 O 2max ) exercise trial (LIE) or a high-intensity (80% of V 4 O 2max ) exercise trial (HIE). The exercises in LIE and HIE were lasted for 20 and 40 min, respectively. All subjects underwent the two trials on separate days, and a randomized cross-over design was used. Blood samples were collected before (Pre) and immediately after exercise, at 3, 6, and 19 h after exercise. Energy consumption during exercise did not significantly differ between the two trials. HIE significantly increased blood lactate and serum lactate dehydrogenase levels (P < 0.05). Compared with pre-exercise levels, the irisin concentrations were elevated at 6 h (18% increase) and 19 h (23% increase) after HIE, but significantly decreased after LIE. The relative irisin concentrations (compared with pre-exercise levels) were significantly greater in HIE than in LIE immediately after exercise, and at 6 and 19 h after exercise (P < 0.05). These findings suggest that irisin secretion after acute running exercise is affected by exercise intensity, independent of energy consumption.

Irisin and Fibronectin Type III Domain-Containing 5 Responses to Exercise in Different Environmental Conditions

“…Increased relative intensity of exercise has been shown to increase the production of irisin (40). However, during the present study the relative intensity (VO2) was greater in the hot compared to the RT (8.3%) and cold (12.4%) conditions.…”

“…Based on previous research that indicates potential increases in irisin due to exercise absent of cold exposure (2,4,5,16,20,33,40), and increases in irisin via a cold exposure absent of exercise (2,20,27), it was hypothesized that exercise in a cold environment would elicit greater circulating irisin and skeletal muscle gene expression of FNDC5 when compared to exercise in International Journal of Exercise Science http://www.intjexersci.com 675 a room temperature and hot environment. Contrary to the hypothesis, the main finding of this investigation was irisin plasma concentrations and FNDC5 mRNA were not different between hot, cold, and room temperature conditions.…”

“…In the United States a growing number of individuals suffer from metabolic and mitochondrial diseases, such as diabetes and obesity, which decrease life expectancy and quality of life (5,23,27,40). Exercise mitigates the negative effects of metabolic diseases and releases a cascade of hormones, such as epinephrine and norepinephrine, that influence physiological alterations Irisin is a cytokine released from the muscle, thus termed a myokine, which is involved in the "browning" of white adipose tissue (WAT) (2).…”

SMAD3 Negatively Regulates Serum Irisin and Skeletal Muscle FNDC5 and Peroxisome Proliferator-activated Receptor γ Coactivator 1-α (PGC-1α) during Exercise

“…Hofmann et al (60) recently reported in a review that of 10 human studies assessing the role of exercise in inducing muscle FNDC5 mRNA expression or increasing circulating irisin, only half reported a positive effect of exercise on FNDC5/irisin induction. Of an additional three studies, only one reported an increase in serum irisin following exercise (27,61,62). However, the 13 studies used different lengths (acute versus chronic) and intensities of exercise, and the human populations studied differed.…”

Actualizaciones Sobre "Irisina" La Nueva Mioquina

“…La capacidad termogénica de la grasa parda está mediada por la presencia de la UPC 1 cuya expresión está regulada por varios factores transcripcionales incluyendo el PPARγ y PGC1α, los que pueden ser inducidos por exposición al frío y al ejercicio a través de la función de la Irisina (figura 1) (28,29). El aumento en la expresión del UPC 1 genera, como uno de sus efectos, el pardeamiento del tejido adiposo blanco transformándolo en tejido adiposo pardo termogénicamente más activo, lo que aumenta el gasto energético total (30,31). El tejido adiposo pardo contiene un alto número de partículas lipídicas y un alto número de mitocondrias (32,33).…”