Long and Hard exercise sessions will reduce weight quickly
Long and Hard exercise may cause your body to produce excessive amounts of stress hormones which begin to break down muscle tissue. It is very important that after you exercise intensely you rest your body for at least a day and eat well to aid recovery. High-intensity exercise is good for heart health, but not effective for fat loss. The more sensible way is to start out at a lower intensity and work your way up gradually.
Genetics also plays an important role in how people respond to exercise. Your development of strength, speed and stamina may be very different from that of other people you know.