There are a few things that you can’t do on the day of donating blood. For your body to have a chance to replace the fluids it lost during donation, you must. Refrain from performing any strenuous activities like heavy lifting. Avoid smoking or drinking alcohol, This will prevent you from experiencing lightheadedness or dizziness. If bleeding occurs at the needle site, apply pressure and elevate your arm for five to ten minutes or until the bleeding stops.