Joe Biden's first ABC interview post-first presidential debate did touch on his cold affecting his performance. It's common for colds to impact overall well-being and cognitive function, which could explain his concern. However, it's not clear from publicly available sources whether his doctors specifically advised him on the seriousness of a cold affecting his overall health if untreated. Generally, medical advice often includes resting, staying hydrated, and monitoring symptoms to prevent complications like secondary infections. Biden's medical team would likely have provided similar guidance to ensure his health was managed appropriately. If you're looking for detailed information on his medical advice or health during that time, official statements or detailed interviews might provide further insight.