This article addresses the relationship of mitochondrial dysfunction and impaired cardiovascular functioning as we age. It specifically mentions rapamycin as improving cardiac functioning through many pathways, but in particular as a potent inducer of autophagy. In fact, they state that you negate the longevity effects of rapa if you impair its upregulation of autophagy.
Also of interest is the mention of mitoQ and mito Tempo as natural supplements to improve mitochondrial functioning.
Most important has to be zone 2 exercise. Mitochondria density and growth responds to exercise demands, hence why people can run marathons very quickly.
Here we see a synergy of rapamycin with melatonin in killing cancer cells. The role of the synergy in promoting mitophagy is discussed. Once again, care must be taken to not overdo this and harm healthy cells through an increased mitochondrial ROS production. Melatonin seems to reduce negative effects of rapamycin while enhancing its positives.