Depends on the type of burnout, but I would caution about doubling down on exercise.
For two reasons:
1: It can be an attempt to avoid working through the issues that led to the burnout. Sometimes it can be like replacing one addiction with another.
2: Exercise is stress, and burnout is a reaction to prolonged stress. Moderate exercise can help, by elevating mood. Heavy exercise in burnout can lead to prolonged fatigue and CFS like symptoms.
And you can get burnout from exercising too much. Had this happen when I was training for some ultra-distance stuff before I had the proper training framework.
For two reasons:
1: It can be an attempt to avoid working through the issues that led to the burnout. Sometimes it can be like replacing one addiction with another.
2: Exercise is stress, and burnout is a reaction to prolonged stress. Moderate exercise can help, by elevating mood. Heavy exercise in burnout can lead to prolonged fatigue and CFS like symptoms.