Functional disorders include metabolic and degenerative disorders. Strength training may be important to metabolic and cardiovascular health. Thyroid hormones are responsible for metabolic activity. Potassium bicarbonate is preferred when correcting hypokalemia associated with metabolic acidosis. Carbohydrates are central to many essential metabolic pathways. The abnormalities of dental development correlate with the age at which metabolic disturbances occur. They also provide protection for organs against metabolic, oxidative, and chemical stresses. Some atypicals are associated with considerable weight gain, diabetes and the risk of metabolic syndrome. Occurs in the absence of any causative skin, metabolic, or neurological disorders. These differences can be credited to sexual dimorphisms in brain, endocrine and metabolic systems. The mechanisms of the complex pathways of metabolic syndrome are under investigation. Sirtuins are a family of signaling proteins involved in metabolic regulation. Oxygen is known to cause toxicity to organisms that lack the required metabolic machinery. Genetic testing is common, particularly when there is evidence of variation in metabolic rate. Weight gain is associated with metabolic syndrome.