Can High-Intensity Exercise Improve Your Memory?

Exercise like walking, swimming, and even dancing have been shown to be good for your memory, but the optimal intensity of that exercise has been unclear ... until now.

Brock Armstrong
5-minute read
Episode #467
Photo of seniors out exercising
The Quick And Dirty
  • Seniors who exercise using "short bursts of activity" see an improvement of up to 30 percent in their memory performance.
  • The "short burst" exercise sessions consiste of four, four minute efforts, separated by a full recovery period. 
  • The participants in the study saw these results after doing this activity three times per week. 

A recent study published in the journal Applied Physiology, Nutrition and Metabolism has some very exciting findings in the fight against memory loss and dementia. I probably don't need to tell you how debilitating dementia can be if you've experienced it with someone you care about. If you haven't, count yourself lucky.

The World Health Organization (WHO) says that around 50 million people worldwide have dementia. Nearly 60 percent live in low- and middle-income countries. Every year, there are nearly 10 million new cases. And to make matters worse, the total number of people with dementia is projected to reach 82 million in 2030 and 152 million by 2050. 

Currently, there's no treatment or cure for dementia or even a way to alter its progression. That makes preventative treatments, such as the study I'm focussing on today, even more exciting. Thankfully, numerous new treatments are being investigated, which are at various stages of clinical trials. So it's not all doom and gloom.

Although there is no cure, there are several things that can be done to support and improve the lives of individuals who have dementia, including (from the WHO):

  • Early diagnosis in order to promote early and optimal management
  • Optimizing physical health, cognition, activity and well-being
  • Identifying and treating accompanying physical illness
  • Detecting and treating challenging behavioral and psychological symptoms
  • Providing information and long-term support to carers

And, as I am focussing on today, movement and exercise play a role in brain health. 

Exercise and your brain

Exercise affects the brain in many ways. To start with, exercise generally increases your heart rate, which in turn pumps more oxygen to the brain. Exercise aids the release of hormones, which provide an excellent environment for the growth of new brain cells. Exercise also promotes brain plasticity by stimulating the growth of new connections between cells in many important cortical areas of the brain. Research from UCLA even demonstrated that exercise increased growth factors in the brain, which makes it easier for the brain to grow new neuronal connections.

While researchers are still trying to determine the exact critical factors that make exercise so good for the brain, the focus seems to be narrowing in on increased blood flow to the brain, surges of growth hormones, and massive expansion of the brain’s network of blood vessels.

RELATED: How Exercise Affects Your Brain.

Seniors who exercised using "short bursts of activity" saw an improvement of up to 30 percent in their memory performance.

Canadian researchers at McMaster University examined the impact of exercise on the brain. Their new study suggests that the intensity at which we get more movement and exercise in our lives is critical. In their research, they found that seniors who exercised using "short bursts of activity" saw an improvement of up to 30 percent in their memory performance, while participants who worked out at a steady-state, moderate level saw no improvement.

Jennifer Heisz, the lead author of the study, quoted in Science Daily, says, "There is urgent need for interventions that reduce dementia risk in healthy older adults ... This work will help to inform the public on exercise prescriptions for brain health, so they know exactly what types of exercises boost memory and keep dementia at bay."

Details of the study

Sixty-four sedentary older adults participated for 12 weeks in one of three groups: 

  1. High-intensity interval training (HIIT)
  2. Moderate continuous training (MCT)
  3. Full body stretching routine—the control group (CON)

All of the participants were healthy older adults between 60 and 88 years old. The researchers used a mnemonic similarity task along with go/no-go and flanker tasks to asses executive functions. The participants were all assessed and monitored before, during, and after the 12-week period as they performed their assigned workouts three times per week. 

The group given the HIIT protocol performed four, four-minute sets of high-intensity intervals on a treadmill with a "recovery period" between each interval. The MCT group performed one continuous set of moderate-intensity aerobic exercise for about 50 minutes. The CON group performed a yoga-like session, similar to what you might find in an assisted living facility. 

The results

To measure the improvements in memory, the researchers used specific tests to assess the function of the newly generated neurons, which are a result of the exercise protocol. The tests can show that the new neurons were more active than more senior ones, which indicates that they're ideal for creating new memories.

Researchers found that any improvements in the participant's fitness level were directly correlated with an overall improvement in their memory performance.

The researchers found that in the older adults who were assigned to the HIIT group, there was a substantial increase in "high-interference memory," a form of memory that gives us the ability to do things like distinguish between a mountain bike and a road bike of the same make or model, for example.

The researchers also found that any improvements in the participant's fitness level were also directly correlated with an overall improvement in their memory performance.

Jennifer Heisz, associate professor in the Department of Kinesiology at McMaster University says, "It's never too late to get the brain health benefits of being physically active, but if you are starting late and want to see results fast, our research suggests you may need to increase the intensity of your exercise."

That raises an important point.

High-intensity is personal

High-intensity is not a one size fits all scenario. A high-intensity workout means different things to different people. 

High-intensity means different things to different people.

For a 20-year-old track athlete, a high-intensity workout is an all-out killer sprint at breakneck speeds. For that same athlete's 75-year-old sedentary grandmother (who also has arthritis in her knees), a brisk aquajog is high-intensity. What's important is that the person feels they're giving the workout their all.

To avoid injury (or worse), it's important to tailor the exercise to suit the current fitness and health level of the individual. So, adding intensity doesn't have to involve a trip to the track—it can be as simple as adding some hills to your daily walk or digging in and increasing your jogging pace between street lamps. Remember that the subjects in the study only did four sets of four minutes with ample recovery time in between to allow their heart rate to come down. There's no need to adhere to a strict Tabata set this time. 

Exercise is a promising intervention for delaying the onset of dementia. Adding some high-intensity bursts a few times per week is proving to be an effective way to administer it.

About the Author

Brock Armstrong

Brock Armstrong is a certified AFLCA Group Fitness Leader with a designation in Portable Equipment, NCCP and CAC Triathlon Coach, and a TnT certified run coach. He is also on the board of advisors for the Primal Health Coach Institute and a guest faculty member of the Human Potential Institute. Do you have a fitness question? Leave a message on the Get-Fit Guy listener line. Your question could be featured on the show.