By in large you can't. Is it because of the radiation from the power plant down the road, the overhead power lines, the lead in the paint in your old house, the transfats in your diet, the coffee you are drinking, the artificial sweeteners you consume, the gasoline fumes you inhale when filling up, the foam insulation in your house, or....How do you verify feeling tired, under par, not quite right, unable to do my job, week, lethargic, dizzy. How could you know what some ones health would be if they not come in contact with this?