Benefits of HIIT

Sorry my story is not so much about keto, but I've been K/IF for 2 years. I am 66 and have always been every active and eaten a fairly responsible diet. What I find interesting is my VO2Max. I have LAM disease. Only women get it as it may be triggered by estrogen. Smooth muscle cells begin to grow in the lungs. 2 CT scans look like Swiss cheese. Dead air space that should have lung tissue. My pulmonary function test was fine. And I have no issues at all. My VO2Max is 41-45 and excellent for my age is 28.I can only attribute this to HIIT.