Do some aerobic exercise every day. For example, just go out for a run, jog, and run for half an hour in the morning or evening. As long as you persist, fitness is very easy.
When you are on vacation, you can go and sit in the park. You can absorb more oxygen in the park, which will make your body more comfortable. The air in the park is better, and the absorbed air also has a good regulating effect on your body.
Control your diet, smoke less, drink less, and eat less greasy and spicy things.