Dear Osa friends,

Last time we spoke, we were welcoming springtime with the equinox and celebrating with more green in our lives (if you missed that letter, you can check it out here). Since then, spring has really sprung here in Portland with blooming daffodils, hyacinths, and magnolias, fresh leaves on trees that were no more than bare sticks a few weeks ago, and longer, sunnier days.

Spring weather really beckons us to invite more movement back into our days. In winter, I retreat into what an acupuncturist friend of mine calls “sloth mode,” which I find fitting for the slower, cozier season. With spring, we can unfurl into what might be called “squirrel mode” (or, insert perky animal of your choice) in which we can shake winter off with our bushy tails and find some new lightness in our step. To inspire spring energy this week, I’m sharing some interesting research on movement. Enjoy!

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Movement is a nutrient

I think most of us feel better when we get movement in our days, but did you know that our muscle cells actually need to move to stay alive? This fact has been illustrated by research showing that when muscles are immobilized, the muscle cells’ mitochondria (recall that these are the subcellular organelles which regulate energy production, cell survival, and many other crucial cell functions) undergo detrimental changes which result in increased inflammation, increased reactive oxygen species generation, and ultimately muscle cell death¹. More specifically, studies in which mice have had a hindlimb immobilized, to mimic the effects of extended sedentary behavior or bed rest, have shown that the density of mitochondria in the muscle cells dramatically decreases in addition to deterioration in the ability of the mitochondria to perform important tasks such as energy production².

Considering how central movement is to muscle health, I think we can consider movement to be a nutrient just like our food and water. And when I say “movement,” I don’t only mean purposeful exercise (although exercise is great, and I’ll touch on that down below). There are so many ways in which we move and engage muscle throughout our days. Even maintaining a good posture when working at a desk, engaging your pelvic floor muscles when standing at the kitchen counter, squatting to pick up your shoes, and really using that diaphragm when breathing all count as nutritious movement for your muscle.

Summary:
Movement = healthier mitochondria = more energy = more vibrant living!

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Time-efficient exercise

If you are someone who really loves to get out on the running trail or on a bike or in the pool and just go at a steady pace for a long time, you might feel frustrated at how difficult it can be to fit that kind of endurance exercise into modern life. The good news is that we can still gain benefits of exercise with a much smaller time investment by mixing in high intensity intervals or (possibly even better) sprint intervals. These workouts involve short efforts near or at your peak capacity, with some rest in between efforts, and they’ve been shown to be very beneficial for cardiometabolic health.

In a 2018 study, four 30-second maximum effort sprints with a few minutes rest in between or five 4-minute efforts of cycling at 75% of maximum effort with a short rest in between resulted in favorable mitochondrial responses which were similar to those elicited by a 30-minute continuous effort at 50% maximum effort ³. These favorable responses included the upregulation of genes promoting the creation of new mitochondria (called mitochondrial biogenesis) and an increase in antioxidant capacity, which we know to be protective of our cells. I think the very interesting finding here was that a total of 2 minutes of sprinting led to benefits comparable to that of 30 minutes of continuous effort.

Aerobic capacity is indicative of mitochondrial health and has implications for our overall health and longevity. One study involving adult men with hypertension, and some with additional risk factors such as diabetes and dyslipidemia, found that aerobic capacity was the strongest predictor of all-cause mortality over a period of roughly 8 years ⁴. A very interesting finding of this study was that greater aerobic capacity compensated for the risk of death associated with having multiple risk factors, such that those men with no additional risk factors but who were sedentary had a greater mortality than those with additional risk factors who maintained a high level of aerobic fitness.

Summary: Getting your heart pumping is a priority for your health, and high intensity interval training is a great type of exercise to try, especially if you are feeling a time crunch.
A couple of caveats: Always plan for at least several minutes of warm-up before any kind of sprinting to prevent injury, and do not do high intensity or sprint workouts every day. Even after accounting for a warm up period, sprint intervals are more time efficient than moderate intensity workouts, and rest days are crucial for reaping the full benefits of your efforts.

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Wishing you a beautiful week,

P.S. Thank you to everyone who has expressed interest in my group program, Macronutrient Mastery. Due to some changes to my schedule, I am unfortunately having to postpone the launch of this program until the summertime. Please stay tuned and feel free to sign up to receive updates at the current landing page for the program here, which I will update with new dates and information as soon as possible.

References

1. Ji, L. L., & Yeo, D. (2019). Mitochondrial dysregulation and muscle disuse atrophy. F1000Research, 8 F1000 Faculty Rev-1621. https://doi.org/10.12688/f1000research.19139.1​https://pubmed.ncbi.nlm.nih.gov/31559011/​
2. Kang, C., Goodman, C. A., Hornberger, T. A., & Ji, L. L. (2015). PGC-1α overexpression by in vivo transfection attenuates mitochondrial deterioration of skeletal muscle caused by immobilization. FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 29(10), 4092–4106. https://doi.org/10.1096/fj.14-266619 https://pubmed.ncbi.nlm.nih.gov/26178167/​
3. Trewin, A. J., Parker, L., Shaw, C. S., Hiam, D. S., Garnham, A., Levinger, I., McConell, G. K., & Stepto, N. K. (2018). Acute HIIE elicits similar changes in human skeletal muscle mitochondrial H2O2 release, respiration, and cell signaling as endurance exercise even with less work. American journal of physiology. Regulatory, integrative and comparative physiology, 315(5), R1003–R1016. https://doi.org/10.1152/ajpregu.00096.2018 https://pubmed.ncbi.nlm.nih.gov/30183338/​
4. Kokkinos, P., Manolis, A., Pittaras, A., Doumas, M., Giannelou, A., Panagiotakos, D. B., Faselis, C., Narayan, P., Singh, S., & Myers, J. (2009). Exercise capacity and mortality in hypertensive men with and without additional risk factors. Hypertension (Dallas, Tex. : 1979), 53(3), 494–499. https://doi.org/10.1161/HYPERTENSIONAHA.108.127027 https://pubmed.ncbi.nlm.nih.gov/19171789/