Exercise: One of the most powerful brain drugs we have

We have an intervention that reduces amyloid accumulation in the brain, improves cerebral blood flow, stimulates the growth of new neurons, reduces neuroinflammation, improves sleep quality, lowers cortisol. Along with other lifestyle modifications, the bulk of multiple large studies has shown regular exercise reduces dementia risk by as much as 30–45%.

It has no serious side effects.

That intervention is exercise.

If I was in practice today, I would give every patient an individualized exercise prescription.

Here's what the research actually supports:

Aerobic exercise is the primary driver of neuroprotection. It stimulates brain-derived neurotrophic factor (BDNF), which is essentially fertilizer for neurons. BDNF promotes neurogenesis in the hippocampus, the brain's memory center, which is one of the first regions affected by Alzheimer's. The blood-brain barrier is strengthened by proteins released by the liver during exercise, which have been dubbed "exerkines" in recent research. The dose of exercise that shows up consistently in the literature is 150 minutes per week of moderate-intensity aerobic activity. That's 30 minutes, five days a week or 50 minutes 3 times a week. Brisk walking counts. Cycling counts. Swimming counts.

Active sports such as regular tennis or pickleball are great substitutes but take care to prevent orthopedic injuries. Dancing might be the most beneficial exercise, as it combines aerobic fitness with improved balance, concentration, and cognitive stimulation.

Strength training adds a separate and complementary layer of protection. Two sessions per week of resistance exercise have been shown to improve executive function and reduce cognitive decline independently of aerobic exercise. The mechanism may be different, partly through IGF-1 signaling and partly through metabolic pathways that reduce insulin resistance, itself a significant dementia risk factor.

The combination of aerobic exercise plus resistance training outperforms either alone. If you're doing both, you're doing it right.

Zone 2 training - low-intensity, sustained aerobic activity where you can hold a conversation is getting significant research attention for its metabolic benefits and may be particularly valuable for brain health over the long term.

And it means that when you sit down with a physician focused on brain health, the conversation about exercise shouldn't be "are you active?" - it should be "what are you doing, how often, at what intensity, and how do we optimize it for your specific risk profile?"

What does this mean practically? It means your exercise routine is a neurological intervention. It means the 45-minute walk you took this morning did something measurable to your brain.

Consistency is what makes the difference. I'm not someone who loves to work out, but I've kept the same personal trainer three times a week for the last 30 years. She ensures the workout stays interesting and challenging by varying the routine. If she didn't show up, I wouldn't exercise. The key is finding a way to integrate it into your daily or weekly routine.

Exercise is one of the most critical parts of enhancing brain health, but it is only one of many important components. In future posts, I will write about sleep, diet, hearing loss, cardiovascular health, stress, supplements, and more

For now, happy exercising.