Reducing dementia risk with exercise

Dr Clare WaltonResearch Manager

Reducing dementia risk through exercise

Dr Clare WaltonResearch Manager

Dementia risk factors% with dementia• Age – the biggest risk factor for dementia

• Genetics

• Environment

Dementia risk factors• Age – the biggest risk factor for dementia

• Genetics

• Environment

modifiable factors

Caerphilly cohort study

• 1979 heart disease study with 2,235 men in Wales• Lifestyle, physical and cognitive health tracked for 30+ years

Those who followed 4 or 5 healthy behaviours:1. Taking regular exercise2. Not smoking3. Healthy weight (BMI 18-25)4. High fruit and veg intake (>3 pieces a day)5. Low-moderate alcohol intake (<3 units a day)

60% reduction in

dementia

Exercise & dementia• More than 50 observational studies looking at physical

activity and cognitive impairment or dementia

• A 2014 review of 28 studies - 25 showed high vs low physical activity was linked to lower rates of dementia.

High physical activity definitions:

• Between 2 and 4 aerobic activities per week

• More than 2 miles walking per day

Combining the studies

Beydoun et al (2014) BMC Public Health, 14: 643

How does it work?

Hippocampal volume Glucose metabolism Beta-amyloid burden

But both groups showed significant memory improvements over the year – no difference!

Erickson et al (2011). PNAS, vol. 108: 3017–3022

120 people (average age 65 years) randomly assigned to 3 days/week of either aerobic exercise or stretching for 1 year

How does it work?

Intervention studies• No intervention studies to directly test the effect of physical

activity on dementia• Studies looking at effect of physical activity on cognition in

older people have produced mixed results

E.g. LIFE study in USA• RCT with 1,600 sedentary adults (70-89 yrs)

• Exercise 5-6 times a week VS weekly health education class

• No difference in cognition or incidence of dementia between groups after 2 yrs

Intervention studies• Meta-analysis of exercise interventions in people with Mild

Cognitive Impairment (Wang et al. J Alzheimers Dis. 2014)

> A small but significant improvement in global cognitive function in exercise groups – clinical significance?

FINGER study in Finland• RCT with 1,260 at-risk adults (60-77 yrs)

• Multi-domain intervention (diet, exercise, cognitive training, blood pressure control)

• Improvements in cognition after 2 years compared to control group

- 2011- 1991

• Dementia rates declining

• Improvements in CVD disease management and prevention (i.e. smoking)

• 1 in 3 cases of dementia could be preventable

Public awareness is poor• Survey of 5400 people in July 2015• Qu: Which of the following do you think regular exercise and physical

activity can have a significant impact on for many people?

Only 36% thought exercise could

reduce dementia risk

Public awareness is poor• 1711 people surveyed were 55 years or older• Qu: Approximately, how many minutes of moderate exercise do you

do during an average week?

Less than 20% reach the recommended amount of activity

In summary• Strong evidence that physical activity is associated with

lower rates of dementia and cognitive decline

• Not enough existing evidence to show exercise interventions can reduce cognitive decline or dementia

• What intensity and duration of exercise is suitable and effective for maintaining cognitive health in older people?

• Public awareness is poor – public health campaigns are needed

Find out more

Lifestyle risk factors:alzheimers.org.uk/ReduceMyRisk

Research funding:alzheimers.org.uk/ForResearchers