Adipose tissue or body fat is loose connective tissue composed of adipocytes (fat cells). Its’ main role is to store energy, cushion the organs and insulate the body. Body fat is also involved in producing hormones. The formation of body fat is controlled through the adipose gene. The adipose tissue located beneath the skin is the subcutaneous fat and the fat around the internal organs is called visceral fat, which protects the organs.
An excess of visceral fat is known as central obesity, and there is a strong correlation between central obesity and cardiovascular disease and also linked to type 2 diabetes, insulin resistance, inflammatory diseases and other obesity related diseases. In females the distribution of body fat around the hips, thighs and buttock poses least potential health risk. At menopause the female fat distribution changes and migrates to the visceral fat increasing the health risk to women. The adipose fat around the body is involved in feedback for hunger and the diet to the brain. The storage of body fat is controlled by the hormone insulin, which is stimulated by high blood sugar levels. Fat is constantly being stored and released in the fat cells. The adipose cell plays an important role in maintaining triglyceride and fatty acid levels and determining insulin resistance. Stress appears to promote visceral fat formation.
The original thought on fat burning for weight loss by the fitness industry focused on ‘the fat burning zone’ (FBZ). This is where the individual exercises to within a specific training zone based on their exercising heart rate. However, the most important factor to consider for weight loss is the total energy expenditure of exercise. High intensity exercise expends more energy that moderate intensity exercise (the FBZ is based around moderate intensity exercise). Therefore, the more energy expended the more weight will be lost. It has been suggested that high-intensity exercise is one of the most effective ways to reduce total abdominal fat. Total energy expenditure is paramount for achieving sensible weight loss via creating negative energy balance. Moderate intensity exercise is not as effective as high intensity exercise for creating prolonged excess post exercise oxygen consumption (EPOC). This is when the body continues to burn energy post exercise, measured by an increased rate of oxygen update following strenuous exercise. Prolonged EPOC is an important factor to consider when prescribing a weight loss exercise programme.
However, high intensity exercise may not be suitable for individuals who have a poor exercise tolerance such as those who are morbidly obese, or have underlying heart disease, or other obesity related conditions. Check with your doctor before starting an exercise programme.