Blood glucose levels and obesity

• Chronic elevation of blood glucose levels

  Endothelium cells take in more glucose than normal, damaging the blood vessels
• Damage to blood vessels by elevated glucose levels

  May lead to atherosclerosis, cardiovascular disease, stroke or peripheral vascular disease
• Damage to small blood vessels by elevated glucose levels


  May result in haemorrhage of blood vessels in the retina, renal failure, or peripheral nerve dysfunction
• Regulation of blood glucose

  1. Pancreatic receptors detect raised blood glucose

  2. Pancreas increases insulin secretion

  3. Insulin activates conversion of glucose to glycogen in liver

  4. Lowers blood glucose concentration
• Regulation of blood glucose

  1. Pancreatic receptors detect lowered blood glucose

  2. Pancreas increases glucagon secretion

  3. Glucagon activates conversion of glycogen to glucose in liver

  4. Increases blood glucose concentration
• Exercise and fight or flight responses

  Glucose concentrations in blood are raised by adrenaline, stimulating glucagon secretion and inhibiting insulin secretion
• Diabetes mellitus


  Inability to control blood glucose levels
• Types of diabetes


  • Type 1
  • Type 2
• Type 1 diabetes


  Inability to produce insulin, treated with insulin injections
• Type 2 diabetes


  Pancreas produces insulin but cells are less sensitive to it, linked to insulin resistance and decrease in insulin receptors in liver
• In both types of diabetes, blood glucose concentrations rise rapidly after a meal and glucose appears in urine
• Glucose tolerance test


  Used to diagnose diabetes by measuring changes in blood glucose concentration over time after drinking glucose solution
• Obesity is characterised by excess body fat in relation to lean body tissue and may impair health
• Body Mass Index (BMI)

  Measure of body fat based on weight and height, calculated as weight (kg) divided by height squared (m^2)
• BMI ranges


  • Underweight: 18.5 or less
  • Normal: 18.5-24.9
  • Overweight: 25.0-29.9
  • Obese: 30.0-34.9
  • Obese: 35.0-39.9
  • Extremely obese: 40 or greater
• BMI can wrongly classify muscular individuals as obese
• Methods to measure body fat

  • Densitometry
  • Skinfold thickness
  • Bioelectrical impedance analysis (BIA)
  • Waist/hip ratio
• Obesity is linked to high fat diets and a decrease in physical activity
• Obesity accounts for 80 to 85 per cent of the risk of type 2 diabetes
• Exercise


  Increases energy expenditure, preserves lean tissue, reduces risk factors for cardiovascular disease