"There is a difference between a leisurely walk and a brisk run.
To engage our longevity genes fully, the intensity of training does matter.
Mayo Clinic researches studying the effects of different types of exercise on different groups found that although many forms of exercise have positive health effects, it's high-intensity interval training (HIIT) - the activity that significantly raises your heart and respiration rates - that engages the most significant number of health-promoting genes, and more of them in older exercisers." From the book Lifespan by David A. Sinclair.
