Physical exercise is beneficial in almost every stage of dementia. There are direct, physically measurable benefits of exercise for the brain, and tangible reductions in the difficulty of caretaking when people who have the condition get exercise.
Exercise helps the brain accumulate its fuel
Exercise enables better sleep
And better sleep has a direct effect on brain health. Physical exercise increases the production of a compound called nitric oxide, or NO. When there is more NO in the brain, people sleep longer and deeper, giving the brain's glympathic system an opportunity to clear out toxic proteins including amyloid and hyperphosphorylated tau, both of which are associated several forms of dementia. Destroying these proteins keeps them from activating inflammatory processes that destroy neurons.
Exercise reduces wandering
People who have dementia are often attracted to physical activity. When they don't get enough physical activity, they may compensate by walking out of their home or care facility. Patients who get more structured exercise wander less.
Exercise reduces 'aberrant motor behavior'
Physical exercise reduces the amount of time people who have dementia are unable to sit still.
Exercise increases gray matter in the brain
A study in Japan found that people living with dementia maintain more gray matter, particularly in a part of the brain known as the nucleus acumbens, which processes motivation, aversion, and reward.
Exercise strengthens the blood-brain barrier
The blood-brain barrier prevents infectious organisms and large water-soluble compounds from entering the brain. Physical exercise decreases the concentration of inflammatory hormones tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1) as well as intracellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), which could "loosen" the blood-brain barrier and allow microbes and harmful substances to come in. At the same time, physical exercise increases the production of increases both brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) transcription to keep the junctions in the matrix of the blood-brain barrier from "leaking".
Exercise increases circulation in the brain
Both Alzheimer's and vascular forms of dementia involve reduced blood flow through capillaries in the brain. Although the loss of capillary circulation is not the driving force of either kind of dementia, maintaining circulation has several benefits:
- Reducing inflammation,
- Sending pulses of pressure to glymphatic system to signal it to clear out "tangled" proteins, and
- Preserving white matter, which is like the cables that connect the "computers" or gray matter in the brain.
Exercise helps the brain repair itself
Scientists don't really know that exercise helps the brain repair itself from direct observation of tissue changes in human brains, but studies of animals suggest that exercise increases the number of new connections in the hippocampus, the part of the brain that is involved in long-term memory and the ability to navigate to reach a destination. The hippocampus also influences attention span and the ability to decide when a behavior is appropriate and when it is not.
Supervised exercise reduces falls
Between 50 and 80 percent of people living with dementia fall at some point in every 12-month period. A fall can be the event that triggers the need for a nursing home. Even when falls don't result in serious injury, they can lead to a loss of self-confidence that results in lesser activity that in turn leads to loss of muscle strength, loss of communication skills, and a loss of independence.
The key to successful exercise to prevent falls in people who have dementia is that it has to be supervised. You don't want people taking falls during exercise to prevent falls. Helpful exercises include supervised stair climbing (in an exercise room, not on actual stairs without assurance of safety), walking with hand and/or ankle weights, and balance training. Exercises applicable to dementia with photographs are available in a book entitled Parkinson's and the Art of Moving, by John Argue.