Exercise Blog Series, Part 3: Exercise as if Your Mind Depends on It

Part 3 of a Series By: Michelle Zong, Jamie Foehl and Zachary Zenko, PhD

 

Exercise has been called a “polypill” (3) because of its plethora of benefits4. This is the third post in a series designed to review some of the many benefits of exercise in an accessible manner. Previous posts can be found here and here. Some academic research will be reviewed, synthesized, and summarized so that people without a background in research methods and statistics can appreciate the findings. The evidence in these posts is by no means comprehensive. Instead, only a glimpse of the available evidence is shared.


Most people think about exercise as a path to good physical health. It turns out that exercise might be beneficial to both our bodies and our minds. Physical activity has been shown to help with cognitive tasks such as memory and problem solving. A healthy mind is important for everyone, but this finding is especially relevant for people who are vulnerable to memory loss – namely, people with Alzheimer’s Disease.

Alzheimer’s is a form of dementia marked by memory loss and general decline in cognitive function to the point of not being able to carry out daily tasks. The disease is most prevalent in the elderly population. In fact, one out of ten people age 65 or older has it!3 It is believed that Alzheimer’s is caused by a combination of factors such as genetics (things we can’t control) and lifestyle (things we can control, like physical activity). While no single lifestyle factor reduces the risk of Alzheimer’s, increasing activity might mitigate risks.

Fortunately, exercising, or any type of physical activity can help. Several studies have shown that exercise protects against Alzheimer’s and improves memory7,9,10,13 In fact, one study found that exercise can actually increase the size of the hippocampus; a part of your brain associated with memory3.

 

What type of physical activity helps?

You might be wondering “What type of physical activity helps?” The exact type of activity varies, but one study found cognitive improvements simply from having an Alzheimer’s patient walk hand-in-hand with a familiar caregiver.

The study was conducted in 2011 by Venturelli and colleagues14. In the study the participants walked for 30 minutes at a time, four times a week with a familiar caregiver. We’ll call these people “the walking group” and we’ll compare them to a “control group” (people who didn’t walk with a familiar caregiver).

 

How do researchers measure cognitive functioning?

The researchers in the Venturelli study measured cognitive function using two different scales. The first scale they used was “The Barthel Index of Activities of Daily Living (ADL).”

This scale lists a bunch of daily activities, such as dressing and taking the stairs, as well as indicating the extent to which the person can do the activity, with or without assistance (see Figure 1).

The scale was administered when the study started and again six-months later, when the study ended. In the walking group, scores improved by 23% compared to the control group, with significant improvements in mobility and self-care measures.

The other scale researchers used is the Mini-Mental State Examination (MMSE).

 

The MMSE measures cognitive impairment by asking people to do things like indicate what day it is, recall a list of three items and count backwards from 100 by sevens. (For further MMSE examples see Figure 2).

 

People in the control group showed a decline of 47% on the MMSE whereas people in the exercise group only declined 13%. Admittedly, cognitive function did decline in both conditions, but the difference between a 13% and 47% decline is massive!

 

Another study, conducted with elderly patients with dementia, had similar findings6. In this study, people started off with one hour of low intensity exercises and built up to one hour of dancing and step sessions. The sessions took place three times a week and lasted for 15 weeks. The exercise group improved in walking ability and cognitive functioning (compared to a control group, that did not exercise). This study used the French Rapid Evaluation of Cognitive Function (ERFC) to assess cognitive functioning. The ERFC consists of 12 sub-tests that measure things like spatial orientation, mental calculation, verbal fluency and memory.

 

So far, exercise is looking pretty good, right?

One thing to consider is the possibility that time with researchers was a confounding variable. In other words, it’s possible that the people in the study benefited simply from spending time with researchers and caregivers (not necessarily the exercise). Fortunately, study12 from 2004 investigated this question. The study lasted three months and the people in it had dementia. Some of the participants did daily exercises supported by music for a 30-minute session whereas the control group had daily, 30 minute, one to one conversations while sitting. The exercise group showed improvements in cognition, as measured by the Mini-Mental State Examination. The results of this study suggest that the exercise, rather than the interaction with the researcher, contributed to improved cognitive functioning.

The studies described above focus on more aerobic and cardio exercises. What about resistance training? One study11 had elderly people do resistance training twice a week. The routine included lower body and upper body exercises, such as leg and chest presses. After six months, the exercise group actually showed slight improvements in cognitive functioning, whereas the control group declined. This indicates that resistance training may not only help preserve cognitive functioning in older adults, it may actually help improve it.

 

Exercise is important for all healthy minds

The aforementioned studies focused on adults who were frail and already had cognitive impairments. What about children and healthy older adults? So far, the research shows that exercise benefits cognitive functioning for other populations, such as children and older healthy adults1,8.

 

Analysis of studies with a combined sample size of 100,000 people!

When researchers want to take a systematic look at previously published research to get insight about a research question they conduct a meta-analysis. A meta-analysis is like a study of studies. This year (2017), Guure and colleagues conducted a meta-analysis on the effects of physical activity on cognitive decline, Alzheimer’s disease, and dementia over time5. The researchers included studies that followed participants for at least twelve months and up to 28 years! The combined sample size of all the studies was over 100,000 people. That’s a large sample size! A big sample is important when trying to determine if research results apply broadly. After analyzing all the studies, the researchers concluded that higher levels of physical activity reduced the chances for healthy individuals to develop dementia or Alzheimer’s, by 21% and 38% respectively. This suggests that exercise might decrease the likelihood of developing a form of dementia

It’s clear that exercise is beneficial for the mind and body. What should you do next time you’re faced with the decision to exercise or not?

Exercise as if your mind depends on it.

 

Michelle Zong is a Research Assistant at the Center for Advanced Hindsight. She holds a Bachelor of Science degree in psychology and economics from the University of North Carolina – Chapel Hill. Michelle can be reached at mzong@live.unc.edu .

Jamie Foehl is a Senior Applied Researcher at the Center for Advanced Hindsight. Jamie can be reached at Jamie.foehl@duke.edu and @jamiefoehl on Twitter.

Zachary Zenko is a postdoctoral associate at the Center for Advanced Hindsight. He has a PhD in Kinesiology from Iowa State University and a background in exercise science with research focuses in exercise psychology. Broadly, his research is aimed at promoting physical activity and exercise behavior by creating positive associations with exercise, making exercise experiences more pleasant, and using behavioral economics. He is also interested in the psychological predictors and consequences of exercise. Zachary can be reached at zachary.zenko@duke.edu and @zackzenko on Twitter.


References

  1. Altenburg, T. M., Chinapaw, M. J. M., & Singh, A. S. (2016). Effects of one versus two bouts of moderate intensity physical activity on selective attention during a school morning in Dutch primary schoolchildren : A randomized controlled trial. Journal of Science and Medicine in Sport, 19, 820–824.
  2. Alzheimer’s Association. (2017). 2017 Alzheimer’s disease facts and figures. Retrieved from http://www.alz.org/facts/
  3. Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., … Kramer, A. F. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences of the United States of America, 108, 3017–3022.
  4. Fiuza-Luces, C., Garatachea, N., Berger, N. A., & Lucia, A. (2013). Exercise is the real polypill. Physiology, 28, 330–358.
  5. Guure, C. B., Ibrahim, N. A., Adam, M. B., & Said, S. (2017). Impact of physical activity on cognitive decline, dementia, and its subtypes: Meta-analysis of prospective studies. BioMed Research International, 2017, 9016924.
  6. Kemoun, G., Thibaud, M., Roumagne, N., Carette, P., Albinet, C., Toussaint, L., … Dugué, B. (2010). Effects of a physical training programme on cognitive function and walking efficiency in elderly persons with dementia. Dementia and Geriatric Cognitive Disorders. 29, 109-114.
  7. Leavitt, V. M., Cirnigliaro, C., Cohen, A., Farag, A., Brooks, M., Wecht, J. M., … Sumowski, J. F. (2014). The Aerobic exercise increases hippocampal volume and improves memory in multiple sclerosis: Preliminary findings. Neurocase, 20, 695–697.
  8. López, M., Asteasu, S. De, Martínez-velilla, N., Zambom-ferraresi, F., Casas-herrero, Á., & Izquierdo, M. (2017). Role of physical exercise on cognitive function in healthy older adults : A systematic review of randomized clinical trials. Ageing Research Reviews, 37, 117–134.
  9. Smith, J. C., Nielson, K. a, Woodard, J. L., Seidenberg, M., Durgerian, S., Hazlett, K. E., … Rao, S. M. (2014). Physical activity reduces hippocampal atrophy in elders at genetic risk for Alzheimer’s disease. Frontiers in Aging Neuroscience, 6, 61.
  10. Ten Brinke, L. F., Bolandzadeh, N., Nagamatsu, L. S., Hsu, C. L., Davis, J. C., Miran-Khan, K., & Liu-Ambrose, T. (2015). Aerobic exercise increases hippocampal volume in older women with probable mild cognitive impairment: A 6-month randomised controlled trial. British Journal of Sports Medicine, 49, 248–254.
  11. van de Rest, O., van der Zwaluw, N. L., Tieland, M., Adam, J. J., Jan Hiddink, G., van Loon, L. J. C., & de Groot, L. C. P. G. M. (2014). Effect of resistance-type exercise training with or without protein supplementation on cognitive functioning in frail and pre-frail elderly: Secondary analysis of a randomized, double-blind, placebo-controlled trial. Mechanisms of Ageing and Development, 136137, 85–93.
  12. Van de Winckel, A., Feys, H., De Weerdt, W., Dom, R. (2004). Cognitive and behavioural effects of music-based exercises in patients with dementia. Clinical Rehabilitation, 18, 253-260.
  13. van Praag, H., Shubert, T., Zhao, C., & Gage, F. H. (2005). Exercise enhances learning and hippocampal neurogenesis in aged mice. The Journal of Neuroscience, 25, 8680–8685.
  14. Venturelli, M., Scarsini, R., Schena, F. (2011). Six-month walking program changes cognitive and ADL performance in patients with Alzheimer. American journal of Alzheimer’s Disease and Other Dementias. 26, 381-388.