Strength Training Is Good for Your Mitochondria Too

July 30, 2023

by Cathe Friedrich

The reason you strength train is to stay strong and functional, not to mention sport a great set of biceps, right? But a lot is going on at a cellular level when you strength train. Inside your muscle cells are tiny organelles called mitochondria. It’s their job to fuel muscle contractions by synthesizing ATP, your muscle’s energy source. To produce the energy your muscles use to contract, mitochondria rely on carbohydrates, fat, and, to a lesser degree, to fuel ATP production.

Without ATP, your muscles would enter rigor mortis and cease to function. (As would you). So, to say mitochondria are important is an understatement. As it turns out, strength training may help improve how your mitochondria function.

Here’s the upbeat news. Research shows endurance exercise, like brisk walking, cycling, or running, boost mitochondria health and improve their function. Endurance exercise, where you elevate your heart rate for long periods, enhances the function of these energy producers in both healthy people and those with health conditions that affect mitochondria, like Huntington’s disease.

But it’s not just endurance training that upgrades the health of your mitochondria. High-intensity interval training does too. According to research, HIIT training and sprinting activate AMPK, a key regulator of how mitochondria function. When you boost your heart rate and consume more oxygen, you set this process into motion and your mitochondria get a boost. But what about strength training?

Strength Training for Mitochondrial Health

Beyond endurance exercise, research now shows working your muscles against resistance stimulates mitochondria biogenesis, the process of producing more mitochondria, and improves the function of these energy-producing structures. Mitochondrial biogenesis is the process by which mitochondria reproduce to form new, more vital mitochondria. And age isn’t a factor. A study found that older adults who resistance trained remodeled their mitochondria, making them more efficient.

While working your muscles against heavy resistance helps maximize strength, research finds that working your muscles using lighter resistance enhances mitochondrial biogenesis too, as long as you fatigue the muscles you’re working.

What changes does strength training cause at the cellular level? Based on the evidence so far, it helps:

Increase mitochondrial biogenesis. (The evidence is strongest for endurance and HIIT training)
Boost the proteins mitochondria use to create ATP aerobically.
Enhance the efficiency with which mitochondria produce ATP.

Healthy Mitochondria Play a Role in Aging Too

Mitochondria age just as other parts of your body do. Inflammation and free radical damage accumulate over time, interfering with their function. Plus, mitochondria decline in number with aging. Studies show that mitochondrial dysfunction, related to aging, may contribute to age-related health problems, including cardiovascular disease and brain aging.

What’s more, the boost in mitochondrial biogenesis that occurs with exercise helps preserve muscle tissue itself. How? Mitochondrial decline contributes to sarcopenia, age-related loss of muscle mass. As we get older, without adequate stimulation, muscles atrophy, and lean muscle mass goes down. It’s one of the main reasons the elderly become frail and have more problems getting around.

Mitochondria Affect Insulin Sensitivity

As you lose muscle due to sarcopenia, muscle cells become more insulin resistant, and the risk of metabolic issues that lead to type 2 diabetes increases. Research shows mitochondrial quality affects muscle quality and the risk of developing sarcopenia. So, keeping your mitochondria healthy and optimizing their function may help ward off sarcopenia and the age-related health problems that come with it.

Now we know why exercise is such good medicine for aging. It boosts muscle strength and function directly, but it also enhances mitochondria biogenesis. In turn, this slows cellular aging. It makes sense, right? As mitochondria age and lessen in number, you produce less energy to sustain life and health. Without adequate energy, tissues suffer, as does your muscle function and stamina.

Key Takeaways

Strength training not only helps you stay strong and functional but also has a significant impact on your mitochondrial health. Mitochondria are tiny organelles in muscle cells responsible for producing ATP, the energy source for muscle contractions.

Endurance exercise like brisk walking, cycling, or running, boosts mitochondrial biogenesis, increasing the ability of your cells to produce energy.
High-intensity interval training (HIIT) and sprinting activate AMPK, a key regulator of mitochondrial function. This helps boost mitochondrial function.
Strength training against resistance also enhances the health and well-being of mitochondria and increases biogenesis.
Inflammation and oxidative damage damages mitochondria and contributes to aging.
Mitochondrial damage and dysfunction increase the risk of age-related health problems.
Exercise-induced mitochondrial biogenesis helps counter sarcopenia and frailty.
Maintaining healthy mitochondria can reduce the risk of developing metabolic issues like insulin resistance and type 2 diabetes.
Adequate energy production by mitochondria is vital for sustaining overall health and stamina.

Putting It into Practice

To maximize the anti-aging effects of exercise and the benefits to both muscle function and your mitochondria, do a combination of strength training and high-intensity interval training on different days. If you don’t feel comfortable doing HIIT training, endurance exercise where you sustain your heart rate for 30 minutes will stimulate mitochondrial biogenesis. However, more intense exercise has an edge. Give your muscles enough time to recover between intense workouts too.

References:

Porter C, Reidy PT, Bhattarai N, Sidossis LS, Rasmussen BB. Resistance Exercise Training Alters Mitochondrial Function in Human Skeletal Muscle. Med Sci Sports Exerc. 2015 Sep;47(9):1922-31. doi: 10.1249/MSS.0000000000000605. PMID: 25539479; PMCID: PMC4478283.
Irrcher I, Adhihetty PJ, Joseph AM, Ljubicic V, Hood DA. Regulation of mitochondrial biogenesis in muscle by endurance exercise. Sports Med. 2003;33(11):783-93. doi: 10.2165/00007256-200333110-00001. PMID: 12959619.
Sun N, Youle RJ, Finkel T. The Mitochondrial Basis of Aging. Mol Cell. 2016 Mar 3;61(5):654-666. doi: 10.1016/j.molcel.2016.01.028. PMID: 26942670; PMCID: PMC4779179.
“Kimberly Huey. Impact of Resistance Training on Skeletal Muscle Mitochondrial Biogenesis, Content, and Function”. Www.Frontiersin.Org, 2023, https://www.frontiersin.org/articles/10.3389/fphys.2017.00713/full. Accessed 22 Jul 2023.
Liu D, Fan YB, Tao XH, Pan WL, Wu YX, Wang XH, He YQ, Xiao WF, Li YS. Mitochondrial Quality Control in Sarcopenia: Updated Overview of Mechanisms and Interventions. Aging Dis. 2021 Dec 1;12(8):2016-2030. doi: 10.14336/AD.2021.0427. PMID: 34881083; PMCID: PMC8612607.
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