Lgnoring yoyr body clock and changing your body's natural rhythms can not only make you depressed, anxious and accident prone, it can lead to much more serious health problems. For example, heart disease, fatigue, ulcers, muscular pain, and frequent viral infections can all result from trying to outsmart our bady clocks. Altering our patterns of sleeping and waking dramatically affects our immune system. While we sleep the body's repair mechanisms are at work; whent we are awake natural killer cells circulate around our bodies and cause more damage. Our digestive system is affected, too - high levels of glucose and fat remain in our bloodstream for longer periods of time and this can lead to heart disease