I do many things to stay fit which amount to a routine of healthy eating, drinking plenty of fresh, clean, filtered water, and exercising regularly – yoga, and walking on the beach.
I also utilize Qigong to remain healthy, and here are the YouTube links for my two favorite Qigong exercises as of late. (Especially given the pandemic.) One is for strengthening the lungs specifically, and the other one is for the overall immune system:
– Judith Dakota, Naval Base San Diego, CA