Recent quotes:

Crunched for time? High-intensity exercise gives same cell benefits in fewer minutes: Mitochondrial changes similar in short sprint exercise versus longer moderate-intensity workouts -- ScienceDaily

In addition, the research team found that fewer minutes of higher-intensity exercise produced similar mitochondrial responses compared to a longer moderate-intensity activity. "A total of only two minutes of sprint interval exercise was sufficient to elicit similar responses as 30 minutes of continuous moderate-intensity aerobic exercise," the researchers wrote. "This suggests that exercise may be prescribed according to individual preferences while still generating similar signals known to confer beneficial metabolic adaptions. These findings have important implications for improving our understanding of how exercise can be used to enhance metabolic health in the general population."

Sustained aerobic exercise increases adult neurogenesis in brain -- ScienceDaily

The results indicate that the highest number of new hippocampal neurons was observed in rats that ran long distances and that also had a genetic predisposition to benefit from aerobic exercise: Compared to sedentary animals, HRT rats that ran voluntarily on a running wheel had 2-3 times more new hippocampal neurons at the end of the experiment. Resistance training had no such effect. Also the effects of HIT were minor. To conclude, only sustained aerobic exercise improved hippocampal neurogenesis in adult animals.