Does exercise help get rid of the depression for your life or just an couple of hours?

No quick fix: Depressive feelings are chronic and recurrent. Exercise helps as does good sleep and good nutrition and good thoughts. But something will always happen to cause depression to surge again. It is a constant and recurrent battle. It is more a plan of action that has to be reset every day - similar to diet management.

Not sure: I wasn't quite sure what you meant by your question. However regular physical activity (30 minutes a day of activity that raises your heart rate - it doesn't have to be exercise) does seem to reduce depression. The effect is not immediate. The short term effect of exercise is a couple of hours of better mood and less anxiety. But regular exercise has more long term effects.