HIIT Improves Cognitive Flexibility in Older Adults 

In the world of athletics, it’s often said, Father Time is undefeated, and the statement could never be truer. Getting older is a part of the natural life cycle and is not something that we should fear, however, there are a few key things to look out for as we age.

One key point in getting older is the fact there are gradual, and sometimes, significant declines in executive functions within the brain. Cognitive functions refer to multiple mental abilities and processes such as learning, thinking, reasoning, remembering, problem-solving, decision-making, and attention span.

Getting older usually entails some type of decline in executive functions, which update, shift, inhibit/release cognitive actions. The decline in executive functions within the brain increases risk of major neuron cognitive diseases like dementia and Alzheimer’s.

To look into how certain types of exercises influence the brain, there was a scientific study published in 2020: “High-Intensity Interval Training Improves Cognitive Flexibility in Older Adults”.

Now, it is already proven that HIIT (High Intensity Interval Training) improves cardio respiratory function and vascular function in comparison to MICT (Moderate Intensity Continuous Training). They hypothesized that intensity of exercise may be a better variable than quantity of exercise when planning a routine to aid in cognitive function. Another secondary purpose of the study was to test whether Vo2 max increases more with HIIT in comparison to MICT.

The study included 69 adults that performed weeks of HIIT, MICT, or total body RT (Resistance Training). Those in the study had no major underlying health issues or injuries. They performed the sessions 3 times a week and had to complete 80% of the total session over the course of the study in order to be included in the final results.

• The HIIT participants performed a 15-second on/15 second off interval loop for 20 minutes, then a complete rest for 5 minutes, then another 20 minutes of 15 seconds on/ 15 seconds off.
• The MICT participants performed 34 minutes of continuous cycling at a steady and pre-specified heart rate.
• The RT participants performed a light warm up on the stationary bike for 3 minutes, then performed a total body workout including: 8 strength exercises on various machines, alternating between muscle groups.
• The scientists attempted to keep track of total energy expenditure, and they did their best to keep all participants within a specified range in order to not skew the results in any direction.

Once each participant finished their respective workout, they were assigned to run through a Stroop Task/Color and Word Test. A Stroop task is a test in which the testee must read names of colors printed in black ink, then those same names of colors printed in different ink than the color it names.

Their version of the Stroop Task was a little different as it contained three portions. The first part of their ST was reading 1 of 4 possible words appearing on the screen: Red, Blue, Yellow, Green. These were mapped to four keys on the keyboard. The second part included the classic reading words of colors that were written in different color ink. The final part included a variation of the second in which the participant had to read the color word instead of the font color itself whenever a certain shape flashed alongside the color word.

After all the sessions were completed by all the participants, the data was gathered and combed over by the scientists and the results were surprising! The key takeaways from their findings include:

• HIIT enhances cognitive flexibility in older adults and has the capacity to result in meaningful improvements in executive function.
• Overall cardio respiratory fitness improved more with HIIT in comparison to MICT and RT trainees.
• There is a greater effect of HIIT on cognitive flexibility than inhibition which is desirable and suggests that aerobic training may have an impact on the most challenging and complex processes going on within our brain.
• HIIT compared to MICT and RT provides greater stimulus for the synthesis of a chemical within the brain that largely impacts cognitive processes.
• It has been observed in other studies that on a longer scale MICT augmented executive functions in older adults and this improvement is associated with the increased blood flow to the brain. The scientists in this study hypothesize that because of the increased blood flow, HIIT is even more favorable to the brain because of the elevated heart rate levels involved in HIIT sessions. However, this was only a theory of theirs, and more studies need to be done in order to definitively say this.

In conclusion, any exercise is good for the mind and the body, however, when thinking about the health of the brain, you may want to consider implementing HIIT-style training once or twice a week. It serves your heart, your lungs, and your mind all in one short, intense session. It’s efficient and can aid in our continuous battle against Father Time.