The research for using high intensity training to build strength and VO2 capacity in heart transplant people was written about in the Journal of Transplantation. This is the link to that article:
I corresponded with the author a couple of times. This is a copy of my email to her and her reply:
WE DO 4 MINUTE INTERVALS BECAUSE RESEARCH IN BOTH ATHLETES AND NON-ATHLETES (EVEN CAD PATIENTS) HAVE SHOWN THAT IT TAKES UP TO TWO MINUTES OF HIGH INTENSITY EXERCISE (85-95% OF HR MAX) TO GET THE STROKE VOLUME UP TO ITS MAXIMUM) AND ALSO- THE TIME SPENT WITH THE STROKEVOLUME "ON TOP" CORRELATES WITH INCREASED EXERCISE CAPACITY (VO2 PEAK)
This seems a little long to me. When I have tried similar workouts, I run very hard for about a minute and do about 10 repeats.
TRY AT LEAST TO KEEP THE INTERVAL FOR 2 MINUTES AND GRADUALLY INCREASE (MAKE SURE YOU DO NOT EXCEED 95% OF YOUR MAXIMUM HR!!)
OUR PRINCIPLE IS THAT THE ACTIVE REST PERIOD SHOULD LAST 75% OF THE PREVIOUS TOUGH INTERVAL (THIS I SSUFFICIENT TIME TO BURN MOST OF THE ACUUMULATING LACTATE, AND ALSO NOT TOO LONG IN ORDER FOR THE HR NOT TO GET TOO LOW - THIS IS ESPECIALLY IMPORTANT IN HTX PATIENTS WITH ONLY PARTIAL REINNERVATION. THIS IS DONE WITH SUCCESS IN A LARGE NUMBER OF STUDIES IN OUR COUNTRY (BOTH HEALTHY AND CORONARY PATIENTS AND PATIENTS WITH HEART FAILURE)2) In other tests of this nature, not related to transplants, the rest interval is longer than the exercise interval. Yours was 4 minutes exercise/3 minutes rest.
YOU RUN A LOT!! AND I WOULD SUGGEST YOU SLOW DOWN A BIT. TRY 3 INTERVAL SESSIONS (ACCORDING TO OUR MODEL) PER WEEK AND DO NOT RUN LONG-DISTANCE THE SAME DAY. IF YOU ABSOLUTELY HAVE TO RUN MORE, DO ANOTHER 2 DAYS OF RUNNING (OR OTHER PHYSICAL ACTIVITY) BUT KEEP AT LEAST 2 DAYS "RUN-FREE"3) I generally run twice a day (3 or 4 miles at a time). Can I just substitute the high intensity work for one of those runs 3 times per week?