Your body temperature fluctuates according to your physical activities circadian rhythms, starting at about 97 degrees Fahrenheit early in the morning. Since mental alertness and physical performance are often linked to circadian rhythms and body temperature, people who engage in such vigorous exercises as running or cycling in the morning may find that these activities can over come – morning “lows” of temperature and alertness.
When you exercise, your body temperature may rise to 100 degrees or more. After you stop, your temperature gradually returns to normal. Exercise will not change the timetable of your circadian rhythms, but it will overcome the rhythms for a time. The chart given below represents how it works.