High-intensity interval training and cognitive function in older adults
As we age, forgetfulness and dementia become significant health concerns, with memory and learning being especially vulnerable. The hippocampus, the brain region largely responsible for consolidating memories, has been shown to decrease in volume with age.¹ Perhaps preventing or reversing hippocampal atrophy (shrinkage) and the associated decline in learning and memory could stave off the onset of dementia.
The Role of Physical Activity in Cognitive Health
In a recent “Ask Me Anything” episode #46 of The Drive, we discussed how physical activity can reduce the risk of cognitive decline through various mechanisms. However, research on the most effective forms of exercise for this purpose has been limited. A groundbreaking randomized study by Blackmore & Schaumberg et al. recently addressed this question by comparing the effects of different training intensities on learning and memory.²
About the Study
The authors conducted a randomized controlled trial involving a six-month exercise regimen with cognitively normal participants aged 65-85 years. Participants were split into one of three groups: - Light-Intensity Training (LIT, n=53): Focused on stretching, balance work, and relaxation, serving as a non-exercise control group. - Medium-Intensity Training (MIT, n=44): Included moderate aerobic activities. - High-Intensity Interval Training (HIIT, n=54): Comprised vigorous aerobic exercises interspersed with short rest periods.
All participants exercised three times per week under supervision, with each session lasting 40-45 minutes, including warm-up and cooldown.
Key Findings: HIIT Outperforms MIT and LIT in Improving Associative Memory
The primary outcome measured was cognitive function, assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Among the various tests, the Paired Associates Learning (PAL) test showed significant differences between groups. The PAL test evaluates visual learning and associative memory, which are among the earliest cognitive domains affected by Alzheimer’s disease.
Results: - HIIT vs. LIT: HIIT showed a moderate effect size (0.72, P=0.004) in improving PAL scores compared to LIT. - HIIT vs. MIT: HIIT also demonstrated a moderate effect size (0.74, P=0.008) compared to MIT. - Long-Term Benefits: Improvements in the HIIT group persisted through follow-up periods up to five years post-intervention. - Enhanced Benefits for Poor Performers: Participants with the worst baseline PAL scores saw even larger improvements (effect sizes of 1.4 and 1.7 for HIIT vs. LIT and MIT, respectively).
These findings suggest that HIIT may be particularly beneficial for improving associative memory, especially in individuals at higher risk of cognitive decline.
Critical Evaluation: Is HIIT the Ultimate Exercise for Cognitive Health?
While the results are promising, it’s essential to interpret them with caution. One major limitation of the study is the experimental design. The HIIT group likely expended more energy (measured in metabolic equivalents, METs) than the MIT group, which could account for the superior performance rather than the intensity itself.³ Normalizing exercise based on energy expenditure rather than time would provide a more accurate comparison of the effects of exercise intensity on cognitive function.
Additionally, the scope of cognitive assessment was narrow, focusing primarily on the PAL test. Other cognitive domains, such as working memory and emotional recognition, did not show significant differences between groups.⁴ This suggests that while HIIT may enhance specific aspects of memory, its overall impact on broader cognitive functions remains unclear.
The Benefits of a Balanced Exercise Routine
A well-rounded exercise regimen remains crucial for overall health and longevity. My framework for exercise emphasizes four pillars: 1. Stability: Enhances balance and reduces fall risk. 2. Strength: Builds muscle mass and bone density. 3. Aerobic Base (Zone 2): Improves fat oxidation and mitochondrial function, combating aging and reducing disease risk. 4. Peak Aerobic Capacity (Zone 5): Increases VO2 max and enhances cardiovascular health.
Key Takeaways: - Zone 2 Training: Boosts metabolic health and combats chronic diseases. - Strength Training: Prevents falls, improves metabolic health, and enhances quality of life. - HIIT: Offers specific benefits for associative memory but should complement, not replace, other exercise forms.
Practical Implications: Finding Your Optimal Exercise Balance
Is memory loss an inevitable part of aging? While studies like Blackmore & Schaumberg et al. provide hope that certain exercise intensities can delay or even reverse cognitive decline, it doesn’t mean HIIT should dominate your exercise routine. Instead, incorporating a variety of exercise types ensures comprehensive health benefits, addressing multiple facets of physical and cognitive well-being.
Recommendations: - Diversify Your Workouts: Combine HIIT with moderate-intensity aerobic exercises, strength training, and stability exercises. - Consistency is Key: Regular physical activity, regardless of type, supports overall health and cognitive function. - Listen to Your Body: Tailor your exercise regimen to your fitness level and health status, gradually increasing intensity as appropriate. - Seek Professional Guidance: Consult with healthcare or fitness professionals to design a balanced and effective exercise plan.
Conclusion
While high-intensity interval training shows promise in enhancing specific cognitive functions like associative memory, it should be part of a balanced exercise routine that includes various intensities and modalities. Embracing a comprehensive approach to physical activity not only supports cognitive health but also promotes overall longevity and quality of life. As research continues to evolve, staying informed and adaptable in your exercise choices will help you maintain a healthy, vibrant mind and body well into your later years.
#Cognitive function #Memory #Workout
Update from Peter Attia, on 2024-09-28Source