When health professionals make exercise recommendations, they tout the benefits of aerobic exercise. No doubt, aerobic exercise is healthy for your heart AND your brain. In response to a heart-thumping, aerobic workout, blood flow and oxygen delivery to your brain increases. This gives your brain a temporary jump start but the real benefit comes with regular aerobic training, not just moderate-intensity cardio, like jogging, but high-intensity interval training as well.
Aerobic vs. Resistance Exercise for Brain Health
In response to exercise that raises your heart rate, your brain forms new neurons or nerve cells and novel nerve cell connections. These changes may enhance learning and give you an additional nerve cell “reserve” that cushions the loss of nerve cells that you experience with aging. The formation of new nerve cells primarily affects an area of the brain called the hippocampus, a portion associated with memory and cognitive function.
No doubt aerobic exercise is a brain-healthy activity – but you might wonder what role resistance training plays in brain health? Does lifting weights or training with resistance bands improve the health of your brain as well? In one study, carried out in rats, researchers compared three forms of exercise:
- Steady-state aerobic exercise
- High-intensity interval training
- Weight training
What they found was when rats performed steady-state aerobic exercise for six weeks, the number of nerve cells in their hippocampus increased by almost 3 times, a substantial payoff! The rats that did HIIT training also developed new nerve cells in the hippocampus but not as many as the steady-state group. Finally, the resistance training group showed no boost in new nerve cells. So, if your goal is to maximize brain health, longer periods of aerobic exercise offers the most benefits.
Unfortunately, aging takes its toll on your brain. Just as we lose muscle with age, we also lose volume in the hippocampus. Like muscles in your body that aren’t trained, the hippocampus decreases in size. At one time experts believed this loss was inevitable but, just as weight training helps you hang onto muscle mass, aerobic exercise helps you retain hippocampal volume. What’s more, it appears that you can, through aerobic exercise, boost the size of your hippocampus even after it’s started to atrophy. What’s less clear is whether exercise beefs up other parts of the brain. Nevertheless, preserving the hippocampus offers benefits since it’s so closely involved in memory and learning.
Does Exercise Training Improve Memory Too?
Based on research, aerobic training reduces the loss of hippocampal volume but does it also lead to measurable improvements in learning and memory? Some studies show that 3 months of aerobic exercise boosts memory by as much as 50%.
The good news is aerobic exercise seems to help brains of all ages, even older and diseased brain. One study found that patients with Parkinson’s disease respond favorably to aerobic exercise and develop new nerve cells in response. Plus, there’s evidence that aerobic exercise may reduce the risk of developing neurodegenerative diseases, like Parkinson’s. Some small studies even suggest that aerobic exercise improves memory and cognition in older adults with mild cognitive impairment, a syndrome that places them at higher risk of Alzheimer’s disease.
The Magic of Exercise
You might wonder why steady-state aerobic exercise offers more benefits than HIIT and why resistance training doesn’t boost brain volume. Research suggests that longer periods of aerobic exercise are most effective for brain health. In response to aerobic exercise, muscle cells, release a chemical called irisin into the blood. This turns on another factor called brain-derived neurotrophic factor, or BDNF that changes the circuitry in your brain
The release of these brain growth factors is only one-way aerobic exercise may boost brain health. A kick-butt aerobic workout also reigns in tissue inflammation and improves the way cells respond to insulin. That’s important since insulin resistance is linked with a number of health problems, including heart disease. In addition, aerobic exercise lowers blood pressure and improves lipid levels, thereby lowering the risk of stroke.
What about Resistance Exercise and Brain Health?
Although there’s not a lot of evidence that resistance training increases the size of the hippocampus, some studies show that it improves “executive functioning,” the ability to analyze, make a decision and execute a task. If you have poor executive function, you could have problems completing tasks on time or even planning the steps you need to take to complete a project. So, resistance training might make you more productive. Plus, there’s evidence that weight training can improve your mental outlook and help ward off depression. Some studies also show that weight training tames anxiety.
It’s not clear how resistance training improves mental health. Some possibilities are that it changes the levels of key neurotransmitters that affect mood, like serotonin and dopamine or it alters blood flow to the brain. Another possibility is that by improving self-esteem, you’re less likely to feel anxious or depressed.
The Bottom Line
For preserving brain health as you age, aerobic exercise offers the most benefits. Even brisk walking offers enough of a stimulus to boost the birth of new nerve cells in the hippocampus. Yet, resistance training may help your brain in other ways – by improving your mood and self-esteem and by enhancing executive function, the ability of your brain to plan and execute projects. The question is whether a mildly aerobic workout, like circuit training, provides enough stimulus to build new brain cells.
One thing’s for sure – you need both aerobic and resistance training in your workouts. Aerobic exercise may be best for preventing brain shrinkage and keeping your memory sharp but strength training keeps you strong and functional. So, don’t think “either-or” but “both.”
References:
PsyBlog. “Study Tests Whether Lifting Weights or Running Grows More New Brain Cells
SharpBrains.com. “Physical exercise: why aerobic exercise enhances neurogenesis and neuroplasticity”
Harvard Health Publications “Regular exercise changes the brain to improve memory, thinking skills”
Resistance Training Improves Mental Health. Amenda Ramirez and Len Kravitz, Ph.D.
IDEA Health and Fitness Association. “Resistance Training Improves Mental Health”Science Daily. “Sustained aerobic exercise increases adult neurogenesis in the brain”
Arch Neurol. 2010 Jan; 67(1): 71–79. doi: 10.1001/archneurol.2009.307.
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