Metabolic syndrome (MetS) encompasses a cluster of metabolic disorders including abdominal obesity, hypertension, dyslipidemia, and insulin resistance . Among them, abdominal obesity is characterized by increased distribution of fat in the central area of the body, which potentially increases the risk of insulin resistance, hypertension, cardiovascular disease and cancer . The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) defines the MetS as having at least three of these disorders: systolic and diastolic blood pressure (SBP and DBP) more than 130 and 85 mmHg, respectively, waist circumference (WC) more than 102 cm (for men) or 88 cm (for women), fasting blood sugar (FBS) more than 100 mg/dl. fasting triglyceride (TG) more than 150 mg/dl, high-density lipoprotein (HDL) cholesterol less than 40 mg/dl (for men) or 50 mg/dl (for women) . Evidence suggests that adherence to regular physical activity and healthy dietary pattern may trigger changes in the expression of circulating appetite-related hormones and/or metabolites and sensations of hunger and satiety, and these responses also appear to depend on exercise intensity in which is important to weight management .
Cholecystokinin (CCK), Glucagon-like peptide-1 (GLP-1), Oxyntomodulin (OXM), peptide YY (PYY) (which are secreted from the small and large intestine), and pancreatic and amylin polypeptides (which both them are secreted from the pancreas) are hormones that affect appetite and hunger and satiety signaling . Unlike other anti-appetite hormones, PYY increases energy consumption along with reducing appetite . Therefore, it has been shown that increased PYY secretion after food consumption may decrease the risk of obesity .
High-intensity interval training (HIIT), and moderate-intensity interval training (MICT) are known to be among common non-pharmacological protocols for metabolism controlling and associated condition such as obesity by regulating hunger, satiety, and appetite perception .Several studies have reported the importance of MICT in improving body composition, cardiovascular fitness, insulin resistance (IR), and lipid profile [8–10]. While other investigations show similar physiological adaptation after either HIIT or MICT . In addition to the beneficial effects of MICT and HIIT in appetite perception and plasma levels of appetite hormones , Matos et al (2017) reported contradictory results .
Furthermore, intake of dietary fiber has been identified to preventive effects on the mentioned metabolic disorders especially obesity . As a dietary fiber, alginate is a jelly polysaccharide and a structural component extracted from brown seaweed. Sodium alginate is the most commonly used alginate, which has been widely used as an additive in the food industry in recent years. Consumption of sodium alginate seems to modulate human appetite by gelling it in the stomach . Sodium alginate affects gastric emptying and promotes a feeling of satiety. consequence, stimulates the appetite hormones secretion (CCK, GLP-1, and PYY) [14, 16].
Despite evidence for the positive adaptations following HIIT compared with MICT concerning aerobic fitness and vascular function, it is still unclear which form of training is most effective for weight control, overall fat loss, or central adiposity . Since limited studies have conducted on the interactional effects of sodium alginate supplementation with different exercise methods on weight loss, body fat, and appetite hormones in people with MetS , the present study aimed to investigate the effect of eight weeks of HIIT and MICT with sodium alginate supplementation on CCK and PYY levels in men with MetS.