Then again, there is runner's high. When I was doing my modest running schedule and did not feel clapped out when I started, I could reach mild euphoria in about 40 minutes. Also appetite suppression and a feeling of being in overdrive. Even as a walker I can achieve this around the 15 mile mark. Nothing beats a long hill walk on a sunny summer day. Even the daily 4 miles is, I hope, preventing the diseases caused by excessive sitting. But does not produce weight loss in the 65 year old female.