Long-distance running is more about endurance You should gain weight, because you usually exercise less. Generally, I run a few laps in parks, communities and school playgrounds in the morning or evening. You insist on jogging every day. Run as many laps as you can at the beginning. You will increase the quantity in a week or so. Keep running. When you are tired, keep running one more lap. Every time I am tired, I insist on running one more lap. Slowly, you can run many laps without feeling tired. Do warm-up exercises before each run. Don't sit down after running. Stand still or take a step first. Keep running every day, and you will gradually lose weight. And your endurance will be significantly improved. Your 800-meter run is sure to reach the upper-middle level. Long-distance running needs persistence. I hope you can keep jogging every day. ..