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Positive changes of our organism from physical activity Essay

Positive changes of our organism from physical activity, 470 words essay example

Essay Topic:physical activity

Physical exercise can lead to changes in the expression of genes that may be important for homeostasis1,2,3,4 (Vaag et al. 1995, Oppert et al. 1995, Teran-Garcia et al. 2005, Mustelin et al. 2008). A threshold of physical activity appears to be required for the correct expression of inherited genes and genotypes, which have been selected by evolution to support physical activity5 (Chakravarty & Booth 2004). The low capacity for carbohydrate and fatty acid oxidation, the insulin resistance, the homeostatic disruption of cellular metabolism in skeletal muscle, and the decreased cardiac output and cardiac maximum volume have been associated with insufficient physical exercise6,7,8 (Eriksson & Lindgrde 1991, McGuire et al. 2001, Booth et al. 2002).
Evidence indicates that individuals with a higher cardiorespiratory fitness have greater longevity, more willingness, less body fat content, better lipid profile and glucose metabolism, among other huge advantages9 (Laaksonen et al., 2002). Nevertheless, the aerobic capacity measured by VO2max, is the best indicator of cardiovascular fitness10 (Bouchard et al., 2011).
The AMP-activated protein kinase (AMPK) can mediate part of the effect of exercise on glucose and lipid metabolism. Furthermore, prolonged activation of AMPK causes chronic adaptations to endurance exercise, such as increased expression of GLUT4 (Glucose Transporter 4) and mitochondrial biogenesis11 (Hardie, 2011).
AMPK is a heterotrimeric protein composed of a catalytic subunit (1 and 2) and two non-catalytic subunits (1, 2, and 1, 2, 3)12 (Winder 2001). The activity of AMPK2 increase in response to exercise of moderate intensity, an increase in fatty acid oxidation13,14 (Chen et al., 2000 Stephens et al., 2002). Therefore, AMPK can be activated by physical exercise, leading to beneficial effects that include increased fatty acid oxidation14,15 (Stephens et al. 2002, Aschenbach et al. 2004) and glucose uptake16,17,18 (Merrill et al. 1997, Hayashi et al. 2000, Mu et al. 2001).
Epigenetic processes are related to metabolic regulation and result from complex interactions between genes and the environment19 (Barres & Zierath 2011). DNA methylation is currently the best characterized epigenetic modification, and it can affect genomic stability20 (Eden et al. 2003). Furthermore, changes in the methylation profile also occur under pathological conditions and in metabolic disorders21 (Ling et al. 2007). In turn, epigenetic imbalance is caused by environmental factors, such as physical activity, diet, and stress22,23 (Mathers et al. 2010, Alegra-Torres et al. 2011).
Although there is some information in the literature regarding the effects of environmental factors, such as physical exercises on metabolic homeostasis, few studies have investigated the involvement of epigenetic changes, such as DNA methylation and cardiorespiratory fitness on glucose metabolism.
The relative importance of both genes and the environment for determining a phenotype can be verified by investigating the phenotype of twins24,25 (Samaras et al. 1999 Boks et al. 2009). In this study, we investigated the cardiorespiratory fitness (VO2max) changes on the PRKAA2 gene methylation profile that encodes the AMPK2 subunit and its relation with metabolic variables in normoglycemic monozygotic (MZ) twins who were discordant for cardiorespiratory fitness. This is the first study involving PRKAA2 gene methylation e cardiorespiratory fitness.

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