Scientists have suspected that the benefits of exercise extend beyond muscle tone, energy and wellness. They believe it might extend down to the cellular level. A study published in the journal Cell Metabolism weighs the effects of different types of exercise on subjects 18 to 30 years of age and 65 to 80 years old.
These subjects performed either weight training, HIIT on a stationary bike or a concurrent workout involving both. Strength training was effective for building muscle mass and strength. At the cellular level, energy-producing mitochondria and protein-building ribosomes responded better to interval training.
Muscle biopsies showed that HIIT increased mitochondrial capacity 49% in younger subjects and 69% in older subjects compared to an inactive control group. HIIT also rejuvenated ribosomes and increased mitochondrial protein synthesis.