Oxygen and depression

Hi my first post. I have some past history with depression. Walking helps a lot! Walking near the ocean even better or bay or salt air. Any exercise that gives the body and brain oxygen. Anyone done any breathing exercises to change mood? This gets some oxygen in the system- that and hot baths with Epsom Salts .

And a good night's sleep-which often can be impossible! I have nothad much trouble lately but the shutting down is painful!