A woman whom I had not seen for a while came in saying she had had the worst winter of her life. She got so sick with infections that she was hospitalized twice. This is a young 27-year-old who runs marathons and is in great shape but now complains of no energy and can't run anymore.

I asked the OD. Toxin? Yes. Inhaled? Yes. Fumes? Yes. Inside? Home? Gas? Carbon Monoxide? All Yes. I asked if she has CO detectors; she says yes, and I told her to make sure they are working.

A month later she looks good and is smiling. Two days after our visit her CO detector blared in her exercise room; an expert found 25 ppm coming off some of her exercise equipment. She removed the offending equipment and now feels great for the first time in 6 months.