Can exercising help dry eyes?

No. Exercise will not improve dry eye. Dehydration induced by exercise without adequate hydration will actually make it worse.
Dry eye treatment. Exercising will not have a significant effect on dry eye. Initial treatment is frequent artificial tears during the day, ointment at night, warm compresses a few times a day, and omega-3 fatty acid supplements. If no improvement, you should see an eye doctor for further evaluation.