MODEL RELEASED. Obese woman. Thermogram of an obese woman reclining on the floor. A thermogram shows the variation in temperature on the surface of an object, measured by the long-wave infrared radiation it emits. The temperature scale is colour-coded and runs from purple (coldest) through blue, green and yellow to red (warmest). Temperature regulation is more difficult in obese people and sweating is increased (pink areas). Blood flow to the lower legs and feet is reduced because of poor circulation, causing them to be cooler than other parts of the body. Obesity increases the risks of developing many conditions, including heart disease, diabetes, osteoarthritis and high blood pressure.