The Effects of Endurance, HIIT and Resistance training on Obesity

This is a website to inform the general public what obesity is and how it can be controlled by various forms of exercise. According to the National Health Service (NHS), the term obese describes a person who is very overweight, with increased levels of body fat (Singla, 2010). Obesity is a condition which is related to a lack of physical activity and an increase in daily caloric intake and a decrease in caloric expenditure, which is a lack of calories being burnt. On average a female should consume around 2000 calories a day and a male it’s 2500. However, obesity is also influenced by other factors such as genetics, socioeconomic standing, metabolism and lifestyle. Currently obesity is measured by using the Body Mass Index (BMI) scale, BMI is worked out by taking the persons height in meters (m) and divided by their weight in kilograms (KG). The BMI scale states anyone underweight has a BMI less than 18.5, normal weight is 18.5 to 24.9, overweight is 25 to 29.9 and obese is a BMI over 30. How obesity works is a person consumes more calories in a day than what are needed to supply the body with energy, the excess calories are then stored as fat. A study found that 40-70% of variation in BMI was related to genetics, individuals who had variations near the FTO or MC3R gene. The FTO gene is known to play a role in controlling feeding behaviour and energy expenditure (Fawcett et.al.,2010)and the MC3R gene which is a protein coding gene. Those who had variations near these genes were more predisposed to obesity, those who had at least one copy of the FTO variation had a BMI which was 0.33 units higher than those without. Those with a copy of the MC3R variation had a BMI 0.26 units greater than someone without the variation (Grey, 2008).

It’s said that obesity affects roughly around 300 million people worldwide and the country with the greatest prevalence of obesity is the United States. From 1991 to 1998, a 70% increase in the prevalence of obesity in 18-29-year olds (Thompson et. al., 2012). The excess energy which is consumed in an individual’s diet is stored as triacylglycerides (which is the main component of body fat in humans) in adipose tissue. Adipose tissue is loose connection tissue composed of adipocytes, which is where energy is stored as fat. Adipose tissue is an endocrine gland, which means it secretes is own hormones straight into the blood, this tissue secretes adipokines which influence metabolic activity, so, the increase in adipose tissue mass due to obesity leads to an increase in the expected concentrations of the adipokines and therefore may have significant effects on macro-nutrient (proteins, fats and carbohydrate) metabolism. The implications of obesity in the adipose tissue alter the concentrations of hormones released from the endocrine glands consist of: insulin resistance, type 2 diabetes, hypertension, premature heart disease and impaired glucose tolerance (Singla, 2010).

In our bodies, the balance between energy intake and energy expenditure is regulated very tightly, which feeds back to the regulatory centres in the central nervous system (CNS), mainly in the hypothalamus, which controls metabolic processes. The regulated storage and mobilization of fat stores maintain the body’s energy stores, therefore, the genes which are involved in these processes could have faults which increase the risk of obesity. Obesity can also cause Type 2 Diabetes Mellitus (T2DM), as they have added pressure on their body’s ability to use insulin to control blood sugar levels accurately, therefore they are more likely to cause T2DM. In obesity, there is a down regulation in the use of GLUT4, GLUT4 helps with the uptake of increased glucose into muscle and adipose tissue. The over expression of GLUT4 leads to an increase in the insulin resistance.

References:

Fawcett, Katherine: Barroso, Ines. (2010). The genetics of obesity: FTO leads the way. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906751/. Last accessed 16th Nov 2018.

Grey, Muir. (2008). Genetics of Obesity. Available: https://www.nhs.uk/news/obesity/genetics-of-obesity/. Last accessed 16th Nov 2018.

Singla, Parul. (2010). Metabolic effects of obesity: A review. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3083889/. Last accessed 16th Nov 2018.