Why all of us need to rethink resistance training
By Austin Perlmutter, MD
In the conversation about how to protect and improve brain health, exercise is always at the top of the list. This is because consistent research shows that people who move their bodies are at lower risk for brain issues like depression and Alzheimer’s disease. By and large, the focus of this conversation is on walking, jogging, and potentially lower-impact movements like tai chi and yoga. In fact, aerobic exercises like these are more widely prescribed by clinicians. But research shows us we need to consider weightlifting more strongly for our brain health.
In this article, we’ll be discussing some of the science backing the idea that weightlifting, or resistance training, can have specific and marked benefits to brain health. To get us started, let’s just explore a few of the studied benefits of weightlifting for brain health:
People who engage in resistance training tend to have better brain health
Healthy people who start weightlifting can improve their brain function, and this benefit is likely to be more pronounced in the elderly
People with cognitive decline had better cognition after starting resistance training
Resistance training may help decrease depressive symptoms
This is notable stuff. And to be clear, there is no pharmaceutical currently on the market that can achieve this combination of benefits. And of course, there’s lots of other research showing the benefit of weight training for almost every other chronic health issue (for example, a recent meta-analysis in the British Journal of Sports Medicine concluded that “muscle-strengthening activities were inversely associated with the risk of all-cause mortality and major non-communicable diseases including CVD, total cancer, diabetes and lung cancer.” Personally, I believe this data is more than sufficient to recommend that everyone at least consider adding weights into their exercise routine. But what’s at play here as it relates specifically to the brain benefits? There are at least 2 major pathways at play.
1. Weight training helps regulate metabolic balance.
Several years ago, researchers at Brown University proposed that Alzheimer’s dementia could be considered “type 3 diabetes,” due to a series of metabolic alterations seen in the brains of people with this condition. Namely, research suggests that as we age, and especially in people with Alzheimer’s disease, there is a drop-off in the brain’s ability to access and use glucose. Additional work shows that people with metabolic dysfunction are at higher risk for developing dementia and depression. This is serious stuff. A 2022 meta-analysis found odds for depression in people with type two diabetes to be 77% higher than those with normal blood sugar. Similarly, a recent Mendelian analysis found that having a higher fasting blood sugar was linked to higher risk for Alzheimer’s disease.
Mechanistically, there are two major connections between brain health and blood sugar worthy of consideration. First, high variability in blood sugar levels and prolonged high blood sugar may both be damaging to the brain through a host of pathways including inflammation. Second, long-term imbalances in blood sugar may come alongside an issue called insulin resistance, which means that our cells (potentially including our brain cells) have more trouble getting the glucose they need.
What do we know about the specifics of the link between blood sugar balance and resistance training?
A single bout of resistance training has been shown to lower glucose and insulin levels for up to 24 and 18 hours, respectively
Resistance training helps lower 3 month blood sugar (HbA1c) measurements in those at risk for developing type two diabetes based on a 2021 meta-analysis
Resistance training has been found to improve blood sugar regulation and insulin requirements in pregnant women with gestational diabetes in a 2020 meta-analysis.
Resistance training improves insulin sensitivity in the elderly based on a 2021 meta analysis published in Journal of Exercise Science & Fitness
2. Weight training helps promote immune balance
In the wake of the pandemic, more people than ever appreciate the importance of immune health to overall wellness. In addition, there’s been a groundswell of interest around the idea of chronic inflammation as a central driver of disease. One of the most important breakthroughs in research around the benefit of weight training concerns the immune system. Specifically, it relates to molecules called myokines, which are tiny signals produced by muscles that can enter and impact the brain.
While the research around myokines is still pretty new, the overall idea is simple: resistance training alters levels of a host of chemicals produced by the muscles that may have beneficial effects on the brain. Some of the best studied-myokines include brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), interleukin 6 (IL-6) and irisin. Many of these and other myokines are believed to directly and indirectly affect the brain’s immune system for the better. Notably, BDNF is strongly tied to the process of neuroplasticity, and is known to help strengthen connections between our brain cells and even help us generate new ones.
In a more straightforward sense, resistance training has been linked to better immune balance and lower inflammation. For example, people with more muscle mass tend to have lower levels of inflammation. Similarly, stronger grip and knee extension abilities correlate with lower levels of inflammatory markers.
What is the best way to capitalize on the benefits of resistance training?
Like everything else in long-term health promotion, brain health strategies should be designed with a goal of sustainability, so that means avoiding injury and creating habits that you’ll enjoy for months to years. Here are some great tips on resistance training for better overall and brain health:
Start light and build your way up. While heavy weights can be great, you can get an excellent workout with lighter weights. Similarly, you don’t have to lift for hours to get brain benefits. Even doing a few minutes of resistance training a day may benefit you.
Consider getting help: If you haven’t done much weight training, consider working with a trainer to learn the ropes and to establish a routine that fits your needs
Classes can be great motivators. There’s robust data suggesting that spending time with others boosts the brain, so combining this with weights could be an excellent double benefit to your cognition. This could be anything from a session at your local gym to following along with an online instructor to CrossFit.
Consider resistance bands. Resistance bands are an excellent way to do resistance training anywhere, and to customize it to your needs. They’ve been shown to be effective at building muscle, and have been linked to better mood
Listen to your body! Having personally injured myself while weight training a number of times, I can’t stress enough the importance of paying attention to your body while you lift and modifying your routine accordingly. If something hurts in a bad way, listen!
Don’t skip the legs! Your legs contain the largest muscles in your body. If you’re looking to get the biggest effect of resistance training, you definitely want to engage your legs. Leg presses, squats and leg extension/curls are some of my favorites.
Consider the nutritional aspects. Research shows that getting adequate protein is key to muscle growth. If you’re new to resistance training, you may need to up your protein intake. Ideal protein intake varies by person and goals, but some data suggests that we also should be consuming more protein as we age to offset age-related muscle loss. Additionally, there’s good research supporting the role of creatine supplementation for brain and muscle health at around 3-5 grams a day