Review the Effect of High Intensity Interval Training on Obesity- Related Hormones

Subject Areas : Open Access

Tohid Mabhout Moghadam ¹ , Mohammad Mosaferi Ziaaldini ² , Mehrdad Fathi ³ , Seyed Reza Attarzadeh Hoseini ⁴

1 - Department of Physical Education and Sport Sciences, Khavaran Institute of Higher Education, Mashhad, Iran
2 - 2. Department of Exercise Physiology, Ferdowsi University of Mashhad, Mashhad, Iran
3 - Department of Exercise Physiology, Ferdowsi University of Mashhad, Mashhad, Iran
4 - Department of Exercise Physiology, Ferdowsi University of Mashhad, Mashhad, Iran

Received: 2020-12-02 Accepted : 2020-12-02 Published : 2020-11-21

Keywords: Obesity, Hormone, High Intensity Interval Training,

Abstract :

Abstract Introduction: Nowadays, obesity is one of the health problems in the world, the incidence of which is spreading. In recent years, with the spread of obesity and metabolic complications caused by obesity, much scientific attention has been paid to the study of adipose tissue. Today, adipose tissue is not considered a static tissue that stores only energy, but is considered a metabolically active tissue. Like the glandular system, metabolic tissues secrete various secretory factors that have auto, para and endocrine functions depending on the extracellular environment. Environmental factors such as diet, physical activity, and metabolic status are the main causes of overweight and obesity; in turn overweight and obesity are also affected by genetic traits. As a general rule, excess body fat is the result of a long-term imbalance between energy intake and energy expenditure. Conclusion: Proper selection of exercises is an important factor in changing the lifestyle of obese children and adolescents and is an effective indicator in the control and treatment of obesity. Physical activity creates a negative energy balance due to increased energy consumption. Recent research suggests that high intensity interval training (HIIT) creates a temporary state of anorexia that delays hunger for a short time after exercise, but this effect is short-term. On the other hand, HIIT plays a role in the changing energy consumption through changes in hunger and appetite signals as well as regulatory peptides at the levels of short to long-term signals in obese individuals. This review article discusses the effectiveness of HIIT in obese people. Keywords: Obesity, High Intensity Interval Training, Hormone   Extended Abstract Introduction Recent advances in obesity research have shown that genetic mutations do not justify the growing trend of obesity, and that environmental factors and lifestyles are more effective. Although some people may be prone to obesity and related diseases as a result of genetic factors, it is not the only cause of obesity, and there are other determinants of the condition (1). Today, the obesity index is expanding due to the change in modern lifestyle, which indicates an increase in calorie intake and a decrease in physical activity, and it is believed that the cause of obesity is really complex and vague and is not well known (5). Several peptides released by peripheral tissues interact with specific areas of the brain, and the secreting neurons release anti-appetite or appetizing neuropeptides that are involved in controlling nutritional behavior and energy consumption patterns (7). Environmental signals can be divided into two main parts: a) appetite-suppressing signals, such as leptin and peptide PYY3-36, which are involved in long-term energy balance regulation and directly in responding to changes in body proportions, b) appetite increasing signals, such as agouti-related protein (AgRp < /em>) and ghrelin, that are involved in acute control of nutritional behavior (8, 9). Recent research suggests that high intensity interval training (HIIT) creates a transient anorexia nervosa that delays the feeling of hunger for a short time after exercise, but this effect is short-term. By focusing on HIIT, one can see the possibility of changing energy consumption through changes in hunger and appetite signals as well as regulatory peptides from short to long signal levels (17). In this article, first, the mechanism of action of hormones affecting appetite is explained and then the effect of HIIT on the response of these hormones is discussed.   Appetite-suppressing hormones Leptin Leptin is an adipokine secreted from adipose tissue which is a major regulator of inflammatory status and glucose and fat metabolism and can be resistant to insulin (18). Leptin levels are directly related to the body's fat stores and respond to changes in the body's energy balance. Leptin levels in obese children and adolescents are 4 to 5 times higher than in peers who arein normal weight (22, 23).   Peptide PYY3-36 Peptide PYY3-36 is associated with short-term appetite which has been observed at different ages of obesity. This anorexigenic peptide covers a wide range of peptides involved in food absorption regulation. PYY is presented in two main forms, PYY3-36 (biologically active form and effective in satiety) and PYY1-36, though many studies have reported total PYY (30). PYY3-36 is released from L cells, especially in the small distal intestine, and is stored at high levels for several hours after eating (34). After absorbing nutrients, the presence of nutrients in the duodenum probably releases a nerve signal or sputum into the distal river that plays an important role in the initial release of PYY3-36, and is then accompanied by direct stimulation of L cells in the ileum. (35). Although some of these peptides are produced and secreted in the brain and hypothalamus, the production of the central and peripheral nervous system and its activities indicate parallel paths in moderating nutritional behavior (36).   Appetite increasing hormones Agouti-related protein (AgRp < /strong>) The Agouti-related protein (AgRp < /em>) gene is a candidate for obesity (52) and an appetizing and stimulating appetite-enhancing peptide .It is involved in nutritional behavior or weight regulation and energy homeostasis, and its plasma levels are higher in obese individuals (53, 54).   Studies have shown that physical activity under normal conditions causes overeating by receiving energy and stimulating Y neuropeptide activity and the Agouti-related protein (AgRp < /em>) in the hypothalamus (8, 55). The negative energy balance for stimulating appetite and increasing food absorption depends on the severity, duration and the type of the exercise, the initial amount of fuel resources and nutritional status (57). Hunger and exercise increase appetite and lead to an increase in negative energy balance and the amount of appetite-increasing hypothalamic and extra-hypothalamic peptides including the agouti-related protein and neuropeptide Y (55, 58).   Ghrelin Ghrelin is a 28-amino acid peptide derived from its precursor, preheproghrelin, which contains 117 amino acids. The ghrelin sequence is located immediately after the 23 amino acids associated with the peptide sign. To detect the hormone, a group of octanivil has been added to the serine amino acid ghrelin No. 3 which is required by the recipient (59). Ghrelin is a hormone that affects the feeling of hunger and long-term regulation of body weight. This peptide hormone is secreted from the gastrointestinal tract, especially the stomach, and plays an important role in increasing the absorption of food and fat mass (61). The findings show that the expression of the ghrelin gene increases during starvation and decreases during satiety. In fact, the plasma levels of ghrelin decrease during positive energy balance and increase during negative energy balance (63). Most studies have shown that fasting ghrelin levels decrease with age (37, 38) and puberty growth in childhood and adolescence (65).   High intensity interval training (HIIT) HIIT is a style of training that is attributed to repeated bouts with relatively short interval activities with high intensity or intensity close to the one  obtained by Vo2peak (68). Due to the intensity of the training, an HIIT bout may last from a few seconds to several minutes, and various bouts are separated by a few minutes of rest with low-intensity activity (69). There is ample evidence that HIIT has a wide range of cardiovascular and metabolic benefits (increased cardiovascular fitness, mitochondrial biogenesis, increased expression of glucose transporter type 4 (GLUT­4) levels, and insulin sensitivity) as long-term continuous training or even more (71 -74). These can help oxidize much body fat. In this regard, various studies have shown that HIIT can be a cost-effective method of body weight management in obese and overweight people (75, 76). Recent research shows that HIIT creates a state of transient anorexia that delays the feeling of hunger for a short time after exercise, but this effect is short-term. This training also plays a role in changing energy consumption through changes in hunger and appetite signals as well as regulatory peptides at short to long signal levels (17). The regulation of energy balance following HIIT involves an organized action and reaction between the central nervous system (CNS) and various organs that is effective in establishing energy homeostasis (54). On the other hand, producing a negative energy balance through exercise may trigger behavioral stimulation to compensate for nutrition which in turn can neutralize the energy loss caused by activity and can alter its effects on weight loss (79). In general, much of the evidence points to the increased levels of fasting ghrelin with weight loss from training. These results show that weight loss affected by training plays a role in normalizing fasting ghrelin levels in obese individuals (86, 90, 91).   Conclusion Most of studies show that HIIT delays the feeling of hunger by creating a state of transient anorexia for a short time after exercise and plays a role by changing the signals of hunger and appetite as well as regulatory peptides from short to long term signal levels.  

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