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Exercise as it relates to Disease/Alzheimer’s Disease: The Role of Physical Activity at Midlife

Introduction to Alzheimer'sEdit

Dementia vs. Alzheimer's According to the National Institute on Aging (NIA)[2]:

Dementia: a term used to explain a brain disorder affecting communication and performance of daily activities.

Alzheimer's Disease (AD): a specific form of dementia affecting parts of the brain that control thought, memory & language.

Unfortunately, the biggest risk factor for developing AD is increasing age. Three in ten people over the age of 85 have dementia.

SymptomsEdit

Symptoms vary between individuals and progress at different rates, as the areas of the brain affected also vary. Other symptoms may include but not limited to:

  • Memory difficulties
  • Loss of enthusiasm
  • Unable to remember people & places
  • Unable to understand questions & instructions
  • Decline in social abilities
  • Emotionally unstable

What is the background to this research?Edit

The aim of this study was to investigate the association between physical activity at midlife, and the development of Dementia and Alzheimer’s Disease. The population of older adults is increasing at an unprecedented rate. Currently, 8.5% of the population worldwide are over the age of 65. An Aging World, a new report published in 2015 projects there will be an increase to approximately 17% by 2050 [3].

This current research into connections between midlife exercise and AD is important as the older population is continuing to increase.

Where is the research from?Edit

The research was conducted in the following departments:

  • Aging Research Center: S Rovio MSc, I Kåreholt PhD, M Viitanen PhD, B Winblad PhD, M Kivipelto PhD
  • Department of Public Health and General Practice: E L Helkala PhD
  • Department of Neuroscience and Neurology: H Soininen PhD, M Kivipelto PhD
  • Department of Epidemiology & National Public Health Institute: J Tuomilehto PhD, A Nissinen PhD

Authors and their work related to Dementia & Alzheimer'sEdit

Ingemar Kåreholt, is an Associate Professor, Senior Fellow and Senior Researcher at The Aging Research Center (ARC) which is affiliated both with Karolinska Institutet and Stockholm University. Kåreholt specializes in health trends in older adults. Ingemar Kåreholt is also a member of the Nordic Brain Network.

Hilkka Soininen, has been the Professor in Neurology since 2000 at the University of Eastern Finland. Soininen has been researching Alzheimer's Disease and Memory Disorders for many years, now concentrating on bio-markers, genetics, neuro-imaging, therapy and prevention of AD [4].

Authors Kåreholt & Soininen are renowned in their area of study, both having published similar studies relating to AD & Dementia.

What kind of research was this?Edit

This study was a longitudinal cohort study, following 2000 participants over a minimum of 11 years. During the original examination and the re-examination, a questionnaire was included to determine the amount of physical activity undertaken by the participants per week. Including a questionnaire may have been a downfall to the study as the answers provided by the participants may not have been reliable and/or consistent.

A longitudinal cohort study is useful for[5].:

  • evaluating the relationship between risk factors and development of a disease
  • the outcome of treatments used over a period of time
  • follow a change over time
  • establish a sequence of events
  • ability to correct the 'cohort effect'

What did the research involve?Edit

The baseline survey included a self-administered questionnaire on health behavior, health status and past medical history. Blood pressure, height and BMI were all recorded. Finally, the presence of various loco-motor disorders was determined. The participants were categorised as having a loco-motor disorder if they presented with at least one of the following:

  • Rheumatoid Arthritis (RA)
  • Arthritis
  • Arthropathy or;
  • Arthralgia of the joints of the extremities or the back

2000 individuals were randomly selected from four independent population based studies after being investigated once during midlife (either in 1972, 1977, 1982 or 1987), and invited to be re-examined during 1998. 1449 (72.5%) participated in the re-examination, 900 females (62.1%) and 549 males (37.9%). All 1449 participants were between the ages of 65-79 years old. During the re-examination in 1998, the survey methods were identical to the midlife survey.

The above section of the method proves two small issues. Firstly the prevalence of AD is much higher in females than it is in males, approximately 62% [6]. The study includes a larger population of females, which means the results could have been alterted if more males were involved. Secondly, the age of the participants are relatively young in terms of AD diagnosis. If the participants were >79 years, the results may again have been different. For this study to be more successful, a second follow up should be included to capture the 85+ population.

Based on their physical activity participation, the participants were then categorised into two groups; active or sedentary. The active group comprises people who participated in leisure-time physical activity >2 times per week at midlife. The sedentary group comprises of people who participated in leisure-time physical activity <2 times per week at midlife.

What were the basic results?Edit

Individuals participating >2 times a week in a leisure-time physical activity had 50% lower odds of Dementia compared with sedentary persons. The association was somewhat stronger for AD than for overall Dementia; those in the active group had 60% lower odds of AD compared to those in sedentary group, even after adjusting for a wide array of potential confounding factors. Of the 1449 participants, results from 1251 participants were available. The participants were categorised into two groups, active (n=515) and sedentary (n=736). Some data was missing.

The results from the re-examination show that 2.9% of participants in the active group developed Dementia, with only 2% developing AD. In the sedentary group, 5.2% developed dementia and 4.3% developing AD in the follow-up. Interestingly, the results show that the percentage of participants in each group categorised with a history of a loco-motor disorder was exactly the same at 29.1%. The percentage of participants with a history of diabetes mellitus and of myocardial infarction were both higher in the active group. The percentage of smokers and drinkers were also higher in the active participants.

What conclusions can we take from this research?Edit

The results from the research show that regular leisure-time physical activity at midlife can be protective against dementia and therefore AD later in life. If an individual implements regular physical activity during their midlife, this can increase their chances of living an enjoyable physical and cognitive life in the future. There have been a number of studies in the more recent years that support this statement. [7] [8]

Practical Advice - Exercise PrescriptionEdit

This study supports exercise as a beneficial way to slow and/or prevent the development of AD & Dementia.

Current research has demonstrated that regular strength-training exercises (2-3 days per week), has the ability to overcome weakness and frailty and the consequences that may follow. Strength-training can build muscle strength, muscle mass, preserve bone density, reduce risk of osteoporosis, reduce the risk of chronic disease such as heart disease, arthritis, type 2 diabetes, and can also improve sleep [9]. Sustained aerobic training and flexibility training are also considered beneficial. Below is a table outlining the different types of exercise, the benefits and some examples [10].

Type of Exercise Explanation Benefits Examples
Aerobic Training Exercise performed at a moderate level of intensity over a long duration Improve physical health, increase blood flow to the brain Walking, Jogging, Dancing, Swimming, Cycling
Resistance/Weight Training Exercising muscles against an external force that provides resistance Increased muscle, tendon & ligament strength, bone density, flexibility, tone, metabolic rate & postural support Squeezing rubber balls, Use of elastic resistance bands, Lifting weights
Flexibility and Balance Increases an individual's range of movement Strengthen spine & supporting muscles, improve coordination & balance Bending, Stretching, Tai Chi, Yoga, Pilates

Further Reading & ResourcesEdit

InformationEdit

Follow the links below for further information regarding Dementia & AD:

Alzheimer's Australia

Alzheimer's Association

Lifeline

ReferencesEdit

  1. [1], Leisure-time physical activity at midlife and the risk of dementia and Alzheimer’s disease, Lancet Neurol, Suvi Rovio, 2005.
  2. [2], National Institute on Aging.
  3. [3], An Aging World: 2015, International Population Reports, W He, D Goodkind, P Kowal, March 2016.
  4. [4], University of Eastern Finland, Neurology.
  5. [5], Longitudinal Studies, Journal of Thoracic Disease, E Caruana, 2015.
  6. [6], Forecasting the global burden of Alzheimer’s disease, Alzheimer's & Dementia, R Brookmeyer, 2007 .
  7. [7], Exercise Plays a Preventive Role Against Alzheimer’s Disease, Journal of Alzheimer’s Disease, Z Radak, 2010.
  8. [8], Protective Effects of Physical Exercise in Alzheimer's Disease and Parkinson's Disease, Journal of Clinical Neurology, T Paillard, 2015.
  9. [9], The benefits of strength training for older adults, American Journal of Preventive Medicine, R Seguin, M Nelson, 2003.
  10. [10], Physical Exercise and Dementia Factsheet 2015, Alzheimer's Australia .