Researchers already recognize that exercise improves sleep, reduces depression, provides “waist management”, maintains muscle, and boosts immunity. Now scientists have found that certain types of exercise may help regenerate key cells that normally decline with aging. Scientists published an article in Cell Metabolism magazine in March that showed that HIIT (high intensity interval training) with cardiovascular exercises like biking and walking induced cells to produce more proteins for energy-making mitochondria and protein-building ribosomes, which help halt aging at the cellular level.The study’s senior author Sreekumaran Nair, an MD and diabetes researcher at the Mayo Clinic in Rochester, Minnesota had 36 women and 36 men aged 18-30 years old (“young group’”) and volunteers aged 65-80 years old (“older group”) in the study. Each group was divided into three different exercise programs: one in which volunteers did high-intensity interval biking, one where volunteers used weights and did strength training, and one that used both strength training and interval training. Then the scientists took biopsies from participants' thigh muscles and compared molecular makeup of their muscle cells to samples from inactive volunteers. Scientists evaluated the subjects’ lean muscle mass as well as insulin sensitivity. The research was led by Matthew Robinson, who at the time was a post-doc and is currently an Oregon State University faculty member.While strength training was effective at increasing muscle mass, the biggest benefits at the cellular level were seen with HIIT. A 49% increase in mitochondrial capacity was observed in the younger volunteers and older subjects saw a 69% increase. Insulin sensitivity, which shows a lower risk of developing diabetes was also seen in the interval training groups. Interval training was not as effective in improving muscle strength, which normally declines in aging. Dr. Nair advises, “If people have to pick one exercise, I would recommend high-intensity interval training, but I think it would be more beneficial if they could do 3-4 days of interval training and then a couple days of strength training," He notes that any exercise beats no exercise. The study was completed to understand how exercise benefits individuals at the molecular level. The energy-producing abilities of our cells’ mitochondria decline as we age. In comparing RNA sequencing and proteomic data from individuals doing different exercises, the scientists found evidence that exercise promotes cells to make more RNA copies of genes coding for proteins in the mitochondria and those necessary for muscle growth. Mitochondrial proteins were also produced via exercise. The increase in muscle protein content was the most impressive finding of the research. Age-related decline in mitochondrial function and proteins needed for muscle building were reversed with high intensity biking in some cases. Subjects’ ribosomes, responsible for making cells’ protein building blocks, were rebooted with the high intensity biking regimen. Mitochondrial protein synthesis was also increased. The increase in protein content explains improved mitochondrial function and hypertrophy of muscle. Exercise is so beneficial for our health in a variety of ways because of its impact on these key organelles. Similar to brain and heart cells, muscle cells wear out over time and are not replaced easily. All three of these tissues are known to decline with aging and accumulate damage. If exercise rejuvenates or stops degradation of mitochondria and ribosomes in muscle cells, it may do so in other tissues. Investigating how exercise impacts these pathways may make aging more targetable. Nair and his scientists are eager to discover how exercise benefits various tissues in the body. They are finding ways that clinicians can zero in on pathways that offer the most benefits. For now, regular, vigorous exercise such as brisk walking or biking is the best way to boost your health. There is plenty of data to promote the idea that exercise is vitally important to delay or prevent aging. Fitness experts suggest 2-3 HIIT workouts per week every other day. Beginners can start with 10-30 minutes. Need HIIT ideas? Try these:To warm up:

• March or jog in place for 30 seconds.
• Stand tall and circle one arm at a time backwards, as if you’re pretending to do the backstroke for 30 seconds each.
• Do a front lunge, side lunge, and back lunge using the same leg, then switch to the other leg and repeat. Continue for one minute.

20-minute workout:Do 15-20 repetitions of each exercise with a 10-second break between each. Set a timer for 20 minutes and repeat the exercises until it goes off.Push-ups: Do traditional pushups or place your hands on a stable chair instead of the floor. Or, do push-ups with your knees resting on the ground.Squats: Keep feet under your hips and your bodyweight in your heels.Butt kicks: Walk or jog in place, kicking your first your right heel up to touch your butt, then your left. Tricep dips: Place your hands on a chair or a low table, with your back to the chair. Place legs straight out while balancing on your palms. Bending from your elbows, lower as far as you can, then press up to original position. Side Lunges: With your bodyweight in your heels and your toes facing forwards, step to the left in a deep lateral lunge, keeping your knee above your toes. Switch legs and repeat.By Lisa Andrews, MEd, RD, LDReferences:

1. Fogelholm M. Physical activity, fitness and fatness: relations to mortality, morbidity and disease risk factors. A systematic review. Obes Rev. 2010;11:202–221.
2. Matthew M. Robinson, Surendra Dasari, Adam R. Konopka, Matthew L. Johnson, S. Manjunatha, Raul Ruiz Esponda, Rickey E. Carter, Ian R. Lanza, K. Sreekumaran Nair. Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans. Cell Metabolism, 2017; 25 (3): 581 DOI: 10.1016/j.cmet.2017.02.009
3. https://www.self.com/story/what-is-high-intensity-interval-training-benefits

PDF Handout: Exercise Regenerate Handout