We have long been advised to exercise our minds with puzzles and new challenges in order to lower the risk of developing dementia in later life, but a new study suggests that physical exercise can have a huge impact too.
The findings came from an analysis of data from a long running health study of 5,362 people born in the same week in 1946 across England, Scotland and Wales called the National Survey of Health and Development.
Researchers at Insight46, funded by Alzheimer’s Research UK and the Medical Research Council (MRC), looked at the physical activity of 468 people from the study who had turned 70; asking how often they walked, swam or played a sport over the past three decades – before, and after they turned 50 – and taking scans of their brains.
The brain scans revealed that those who reported exercising as little as once or more a month before the age of 50 also tended to have less shrinking in their hippocampus, “a really important part of the brain... that is usually starting to decline and that is responsible for the early signs of dementia,” according to Dr Sarah-Naomi James from the UCL Dementia Research Centre and the MRC unit for lifelong health and aging at UCL.
Even when key signs of dementia were present, such as the build-up of a protein called amyloid, exercise was associated with better cognitive functioning at age 70.
Surprisingly, these results were even more pronounced for women than for men.
Though Dr James says that there is more work to be done to confirm the link, the level of intensity of exercise as well as the kind of activity people were doing in their 30s and 40s mattered too.
How does it work?
There are a number of ways that exercise can protect your brain, says Dr Vikram Murthy, GP & co-founder of the Harley St clinic Murthy Health.
Enhanced blood flow from aerobic exercise increases the supply of oxygen and nutrients to the brain which are essential for neuronal health. Meanwhile, regular physical activity promotes the production of brain-derived neurotrophic factor (BDNF), which supports the growth and maintenance of neurons, enhancing the brain’s plasticity and resilience.
"Exercise also helps modulate the body’s inflammatory response, decreasing chronic inflammation that can contribute to neuronal damage and cognitive decline," he adds.
But what exercise works best?
Aerobic exercises
Any exercise which elevates the heart rate has shown significant benefits in reducing dementia risk, says Dr Murthy. " Activities such as brisk walking, jogging, cycling, swimming and dancing are particularly effective. For instance, engaging in regular cardiovascular workouts can decrease the risk of dementia by up to a third for middle-aged individuals."
Incorporating strength training
Exercises like weightlifting or resistance band workouts, can also be beneficial, says Dr Murthy: "these activities not only improve muscle strength but also support brain health by promoting the release of growth factors that aid neuronal survival and function."
Light-intensity activities
Even light intensity such as leisurely walking or gardening, have been associated with a reduced risk of dementia, he stresses, emphasising that any form of physical activity is better than none: "In summary, engaging in regular physical activity, especially aerobic exercises that raise the heart rate, is associated with a reduced risk of developing dementia. Incorporating both aerobic and strength training exercises into one’s routine can provide comprehensive benefits for brain health."
David Thomas, the head of policy and public affairs at Alzheimer’s Research UK says that "The evidence shows that it’s never too early or late to start making positive changes,” and “while there is no surefire way to prevent dementia, there are some things within our control that can reduce our risk".
In fact, research suggests that small changes to your sleep schedule could also help lower your dementia risk.
The importance of sleep
A study from the First Affiliated Hospital of Soochow University in Suzhou, China followed 7,683 people as part of a long-term health study to see if sleep patterns had any effect on how people age
When the researchers looked at the sleeping patterns and compared them to the biological ages from the blood test they found that an extra hour or two at the weekend reduced the risk of premature aging by 34%.
How does sleep act as a reset for our bodies? One suggestion is that disrupted sleep is thought to lead to the release of unstable and harmful molecules which can damage cell DNA and speed-up aging. Another suggestion is that high quality sleep may lower inflammation in the body – which has been increasingly been linked to health problems such as dementia.
