NCD Watch

Be Physically Active to Reduce Dementia Risk

23 Oct 2017 (Mon)

Dementia is a significant public health concern. In Hong Kong, local studies observed an increasing trend in the percentage of people with dementia. The number of people aged 60 and above with dementia is projected to soar from about 103 400 people in 2009 to over 332 600 people in 2039.

Dementia is a chronic and progressive syndrome that affects how the brain works, particularly the ability to remember, think and reason. The impairment in cognitive function is commonly accompanied by deterioration in emotional control, social behaviour, and ability to perform everyday activities. Dementia is caused by a variety of diseases and injuries that primarily or secondarily affect the brain. For example, Alzheimer’s disease is the most common type of dementia in which the brain cells degenerate and die because of a build-up of abnormal (beta-amyloid) proteins in the brain. Vascular dementia is the second most common dementia type caused by a reduced blood flow to parts of the brain, usually due to a series of minor strokes.

Since a cure for dementia is not yet available, risk factor modification remains the cornerstone for preventing it. One of the most promising preventive strategies is aerobic physical activity, such as brisk walking, practicing Tai Chi and playing table tennis. Through plausible biological mechanisms, physical activity can enhance neurogenesis and synaptic plasticity or inhibit the accumulation of beta-amyloid in the brain, thereby reducing the risk of dementia.

At present, it remains unclear about the best possible type and amount of physical activity that help prevent dementia in older adults. For optimal health, the World Health Organization recommends adults (including elders) to engage in at least 150 minutes of moderate-intensity aerobic physical activities, or 75 minutes of vigorous-intensity aerobic physical activity, or equivalent amounts throughout the week, in bouts of at least 10 minutes in duration. For those people who are frail or are living with a chronic disease, they may consult family doctor for a customised exercise prescription.

In addition to staying physically active, no smoking, eating a balanced diet, refraining from alcohol use, taking part in intellectual and leisure activities, staying socially active, stress management as well as meticulous control of body weight, blood pressure, blood sugar and blood lipids can help maintain a healthy brain and reduce the risk of dementia. To know more about healthy ageing, please visit the website Elderly Health Service of Department of Health at http://www.info.gov.hk/elderly .