Resistance Training: Genetics, Research Studies, & Background Science
Plus - looking forward to 2025 and back on 2024
This is the time of year when everyone is looking back at the past year, looking forward to goals for the new year, and starting a new exercise routine. I'm going to cover it all in this one email -- and then get back to work on new things!
For your exercise resolutions:
I have a brand new article for you on genetic variants related to muscle mass gains from resistance training. In it, I look at how muscles grow, the signals sent by muscle contractions, and how your genes interact with different aspects of resistance training. There's a tremendous amount of research on this topic, and I feel like I've only scratched the surface in this (long!) article.
For you runners, I have started a draft on aerobic and endurance genetic variants, VO2 max, etc. that I will (hopefully) have finished in a week or two.
Goals for 2025:
This March will mark the 4th anniversary of the launch of Genetic Lifehacks as a membership site and my full-time, all-out endeavor. My goal this year is to raise awareness of the treasure trove of information found in a relatively inexpensive genetic test. Whether someone joins as a member or not, I want to spread the word that understanding the root cause of a health condition is possible and that there is a massive amount of research available to optimize health and prevent chronic disease.
I would really appreciate it if you all would help me with this! Whether through social media or good old-fashioned face-to-face conversations, let others know that there are solutions and that understanding the science can lead to personal health.
Also in the works are updates to the site's functionality, expanded reporting options, and ways to track which lifehacks you're doing and why.
Best of 2024:
I published over 40 new articles in 2024, some big and some small. Here's what sticks out in my mind as most important:
If you have a minute, hit reply and let me know what you found helpful on Genetic Lifehacks this year -- or what you would like to see in 2025!
With over 15,000 people on this email list, I may not be able to respond to everyone, but I love hearing feedback on what works and what you would like to see more of.
Wishing all of you the best in 2025,
~ Debbie
Resistance Training: Genetic Interactions and Personalized Plans
Key Takeaways:
~ Muscle strength is approximately half genetically determined and half due to lifestyle and exercise.
~ Strength training increases muscle mass through myokines produced by muscle contraction and repair of microtrauma from maximal effort.
~ Genetic variants play a role in how much muscle mass improves with training, the response to myokines, and recovery time.
The goal of this article is to explain how resistance or strength training increases muscle mass, why it’s important for everyone’s health, and how to maximize the efficiency of muscle gain.
Genetics, Weight Training, and Muscle Gains
Resistance training involves contracting muscles against weight to increase strength, power, endurance, and more. This type of strength training covers what people think of as weight lifting as well as body weight exercises, such as pushups, and resistance band workouts.
The heritability of strength measurements is around 50-60%.[ref] So while anyone can increase their muscle mass by lifting weights, there’s a fairly wide range in the amount of muscle that people gain. Not everyone will end up looking like Arnold Schwarzenegger or The Rock; genetics play a big role in how much muscle someone can easily gain without using performance-enhancing drugs.
Genome-wide association studies show that gains from training are influenced by multiple genetic variants — a polygenic trait. Moreover, people with similar genotypes respond similarly to exercise training.[ref] The research on genetic variants for athletic or strength training is extensive, but many of the studies show inconsistent results.[ref] Included in this article are genes that have both high-quality human studies and animal studies showing the mechanism of action.
Understanding your genetic propensity to gain muscle (or not) can help you prioritize the right supplements and training routine.
Context: Why is muscle important for everyone’s health – especially as we age?
Skeletal muscle plays an essential role in everyone’s metabolic health by absorbing glucose and regulating blood sugar levels. Loss of muscle mass contributes to metabolic disease.[ref]
Muscle power is essential in healthy aging – whether you are overweight or not.
A recent study of more than 2,500 people over the age of 65 looked at the importance of muscle strength in mortality risk. The study divided the people into four groups: lean + powerful, overweight + powerful, lean + weak, and overweight + weak.
The results showed that even with a BMI over 30 (overweight or obese), those with strong muscles had a significantly lower risk of all-cause mortality. The lean + weak and overweight + weak groups were both at a higher all-cause mortality risk.[ref]
What I've been reading:
1.) Mitochondrial fatty acid oxidation drives senescence
Cellular senescence is the irreversible state when a cell can no longer divide and gives off inflammatory signals so that it will be removed by the immune system. This study shows that the DNA damage response signal to the mitochondria is what triggers a series of steps leading to senescence. Importantly, part of the path to senescence involves enhanced fatty acid oxidation in the cell, and overactivation of fatty acid oxidation alone can induce senescence.
2.) Time-restricted eating and thyroid function
Time-restricted eating involves just eating during certain hours of the day - and then not eating for a period of time overnight. Essentially, it shortens the amount of time you're eating and lengthens the overnight fasting window. This new study showed that time-restricted eating (with or without carbohydrate restriction) improved thyroid function and had other metabolic benefits in people with metabolic syndrome. The study used an 8-hour eating window (e.g. eating breakfast at 10 am and finishing dinner by 6 pm).
3.) Plasticlist.org
This website is posting the results of testing common, off-the-shelf foods and restaurant takeout for plastic content. It is eye-opening and concerning (to me) to see this quantification. The report section is worth reading also.
This is so interesting. I have been wondering about this since I do some weight training with "heavy for me" dumbbells and other weight bearing exercises in order to help with sarcopenia. I did a significant amount of weight training in my early forties and gained significant muscle but don't know if that will carry over now. I'm not able to do nearly the same amount of training due to chronic neck pain and age. Again...so helpful and interesting Debbie!