Background & Aims: Obesity leads to increased health risks and increased economic burden. Obesity, especially in the long term and visceral type, is the cornerstone of the pathogenesis of diabetes. Depending on race and gender, 50 to 90% of type 2 diabetics are overweight and obese, a rate that has been reported to be higher in older patients. The pathophysiological pathways behind this association are complex and ultimately lead to insulin resistance and secondary cell dysfunction. Adipose tissue accumulation produces a range of metabolic and hormonal changes that gradually disrupt the insulin signal transduction pathway and manifest as increased insulin resistance in adipose tissue, liver, and skeletal muscle. On the other hand, it should be noted that the reduction of insulin sensitivity at the cellular level is a natural result of aging. One of the most important compensatory mechanisms against insulin resistance is the increase in pancreatic beta cell mass. This increase in pancreatic cells regulates the dynamic balance between neogenesis, proliferation and apoptotic processes in the islets of Langerhans, which is age-dependent. Are, reflects. But genetic predisposition and aging contribute to beta-cell dysfunction, which, along with chronic glucotoxic and lipotoxic effects, manifests itself in the development of insulin resistance in obese individuals, resulting in impaired glycemic control and diabetes. Nowadays, the basic principles of diabetes control are knowledge and awareness, control of diabetes complications, diet, medication and physical activity, which the low cost and non-pharmacological nature of physical activity increase its therapeutic importance. On the other hand, the beneficial effects of exercise on aging and the side effects associated with it are not hidden from anyone. One type of exercise that has been considered in the control and management of diabetes is high-intensity interval training (HIIT). Due to the characteristics of HIIT and its effects on glucose, insulin, insulin resistance and weight, it has been considered by researchers today, although the same results are not reported, which requires further studies in this field. Dietary supplements, on the other hand, are a form of complementary and alternative therapies that are widely used by the general public, including diabetics. One of the best supplements available is Spirulina Supplement. Spirulina may be helpful in preventing diabetes; because it is low in calories, and contains large amounts of vitamin B1, which improves the metabolism of sugars in the body, it also contains vitamin B2, which helps burn calories, prevents obesity and contains Vitamin B6, which is effective in making the hormone insulin in the body. Increased inflammation due to aging, which also leads to diabetes, and the anti-inflammatory effects of regular physical activity and spirulina supplementation have led researchers to hypothesize that the two may have synergistic effects that could have an optimal effect on Reduce obesity and diabetic complications. The aim of this study was to investigate the effect of eight weeks of high-intensity interval training with spirulina supplementation on weight changes and glucose indices in obese elderly diabetic rats. Methods: This research was of experimental and applied-developmental type. For this purpose, 40 old male Wistar rats (20 months) with an average weight of 280 to 325 grams were purchased and transferred to the laboratory. Then, the standard diet of field rats was calculated and based on that, a high-fat diet derived from soybean and animal oil was prepared and used. The rats were on a high-fat diet for eight weeks. Rats need 10 grams of pellets per 100 grams of body weight per day (standard diet of rats and 10-15 ml of water). The composition of rat pellets included carbohydrates: wheat flour, barley, bran and corn. Protein included: fishmeal powder and soybean meal and fat included soybean oil and a mixture of animal oils. However, in this study, rats had free access to the researcher's high-fat food and the amount of water they needed. The high-fat diet for weight gain consisted of 40% fat, 17% protein and 43% carbohydrates, which were prepared in this study according to livestock and poultry experts. After the weight of the rats reached more than 310 grams according to the Lee index; Diabetes was induced, then HIIT training began. To do this, after a 12-hour period of malnutrition, diabetes was induced by intraperitoneal injection of STZ (Sigma Germany). For this purpose, STZ was first dissolved in sodium citrate buffer solution with pH = 4 and injected into field rats at the rate of 40 mg / kg body weight. After five days, the rats' blood glucose levels were assessed and if the level was more than 300 mg / ml, the rats were diagnosed as diabetic. Blood glucose concentration was measured using blood samples collected from the tails of animals by a glucometer (Buerer GL42 model, made in Germany) and glucose oxidase enzyme method. The criterion for being diabetic was blood glucose concentration higher than 300 mg / 100 ml. The living conditions of the animals in the control group were similar to those in the exercise group except for daily exercise at other times. Then they were randomly divided into 5 groups of 8. Groups include HIIT, HIIT+spirulina, Spirulina, Sham and Control. Then, animals for 8 weeks, 5 sessions per week, HIIT (including running on a treadmill with a maximum of 90% VO2max for 30 seconds, the first week with 5 repetitions and one repetition was added every week) and throughout the training period, the control group did not do any training. Changes in weight, glucose, insulin and insulin resistance were measured by standard methods. Data analysis was performed by one-way ANOVA and Tukey post hoc test using SPSS software. Results: There was a significant difference in fasting glucose, insulin and insulin resistance between the groups (p = 0.0001). The results of Tukey post hoc test showed that HIIT and supplementation caused significant improvements in glycemic index values compared to control and sham groups. The most improvements were observed in the HIIT + supplement group, which showed the interactive effect of independent variables. HIIT and supplementation caused significant changes in weight between the studied groups. After the post hoc test, it was found that the HIIT + supplement group had more weight loss than the control and sham groups (p = 0.0001). Conclusion: In general, weight gain and body fat percentage are directly related to increased insulin resistance, and the presence of these two factors increases the risk of diabetes. On the other hand, diabetes is one of the consequences of aging and for the treatment and control of diabetes, especially in old age, in addition to drug therapy, it has been shown that exercise with insulin independent mechanisms activates muscle glucose uptake. Although the role of HIIT in diabetic and non-diabetic populations has received considerable attention among a variety of sports activities today, its prescription for diabetics has not yet been fully studied, including improving health and reducing complications. Diabetes depends on factors such as the intensity of exercise; For example, six months of moderate-intensity exercise and high-intensity exercise improved insulin sensitivity by 40 percent and 85 percent, respectively. HIIT also showed a greater increase in insulin sensitivity, which in turn Increases muscle glucose uptake in humans and healthy and obese animals. Also, this type of exercise has been useful in improving athletic performance, increasing the physical fitness of healthy people and treating and rehabilitating some diseases, and on the other hand, the energy cost of this type of exercise is higher and improves aerobic fitness. Research has shown that a lack of time to engage in regular exercise and lower blood sugar, even up to 48 hours after regular exercise sessions in people with diabetes, is one of the main reasons these patients do not engage in exercise. That all these cases have been resolved in HIIT. Spirulina can also be effective in weight control and diabetes due to its very rich composition. According to research on the effect of spirulina on blood sugar in research, the effect of this supplement is mainly attributed to the water-soluble part of this algae, which is composed of a protein called phycocyanin and acts as a hypoglycemic agent. In addition, the fiber in spirulina supplementation, which reduces glucose uptake into the gastrointestinal tract, is also shown to be effective in lowering blood sugar. Since the most appropriate dose and timing of intervention for a better response of the body to spirulina supplementation is still inconsistent in the research background, the present study may emerge as a new idea alone in interaction with HIIT for better treatment and control of the index. Sugar and weight should be considered in these patients. According to the obtained results, this study can be used by all researchers who are looking for appropriate and low-risk treatments to treat or control diabetes and weight loss, especially in the elderly. [ABSTRACT FROM AUTHOR]