exercise & ageing
Beginning a regular exercise programme at any age can bring benefits to the brain
TABLE 1. THE EFFECTS OF 30 MINUTES OF MODERATE TO VIGOROUS AEROBIC ACTIVITY
Stimulates brain-derived neurotrophic factor (BDNF), which helps neurons and dendrites grow and thrive
Causes neurons to fi re more effi ciently
Increases levels of vascular endothelial growth factor (VEGF) and insulin-line growth factor (IGF-1), which build and maintain activity within the cell circuitry
Increases the generation of neurons in the hippocampus, an area of the brain which is associated with memory Balances brain neurotransmitters and hormones, which enhance the body’s function Gets oxygen and glucose to the brain faster by strengthening the cardiovascular system Strengthens dendritic branching through repetitive gross-motor movement
Reduces obesity (obesity leads to cardiovascular disease, diabetes, high cholesterol and high blood pressure, which are all risk factors for dementia/Alzheimer’s)
Meanwhile high cholesterol
increases the risk of dementia by 43 per cent. People who are obese are twice as likely to suffer from dementia, and if we factor in high blood pressure and high cholesterol – conditions that often accompany obesity – the risk may actually be six-fold. As we age, cells in the body gradually
lose their ability to adapt to stress. Neurons in the brain are affected in much the same way. Synapses erode when neurons get worn down from cellular stress, eventually severing the connections between them. With this decreased activity, the dendrites physically shrink and wither. If this decay outpaces the new construction of connections, we begin to see problems with mental function. Stress also causes our adrenal glands
to release a chemical called cortisol. Chronically high levels of cortisol lead to cell death in the hippocampus – the area of the brain that’s associated with both long- and short-term memory
and spatial orientation. Chronic stress can also contribute to depression and anxiety disorders, which interfere with normal memory processing, especially as people age. Learning to manage and minimise stress may have a benefi cial impact on brain health; exercise can play a key role here.
EXERCISE CHANGES THE BRAIN A great deal of research supports the positive impact of regular aerobic exercise on the ageing brain. For example, a 2005 study by Kramer et al looked at healthy adults between the ages of 60 and 75 and found that mental tasks involved in executive control
– monitoring, scheduling, planning, inhibition and memory – improved in a group doing aerobic exercise, but not in a control group. Longitudinal studies have drawn similar conclusions. Regular exercise keeps the brain
functioning optimally through the ways listed in table 1, but let’s look at these points in more detail.
Research supports the positive impact of aerobic exercise on the ageing brain
48 Read Health Club Management online at
healthclubmanagement.co.uk/digital Aerobic exercise increases brain-
derived neurotrophic factor (BDNF), which is the most prominent in a family of proteins referred to loosely as neurotrophic factors. BDNF has a fertiliser effect on the brain’s neurons and dendrites, helping them to grow and fl ourish. Tellingly, in 1990 there were a dozen papers on BDNF; now there are more than 5,500. BDNF plays a signifi cant role in
neurogenesis, which is the process of stem cells dividing and developing into functional new nerve cells (neurons) in the brain. Studies have confi rmed that neurogenesis occurs in the adult human, with the hippocampus being the major area for nerve cell growth: a 1998 study by Eriksson et al indicated that the human hippocampus retains its ability to generate neurons throughout life. Regular aerobic exercise also
increases insulin-like growth factor (IGF-1) and vascular-endothelial growth factor (VEGF), two proteins that serve to build and maintain activity within the cell circuitry (the infrastructure of neuronal connections). So exercise both spawns neurons and
stimulates an environment that enriches their growth and survival. Aerobic exercise also increases levels
of important neurotransmitters – brain chemicals that transmit signals across
april 2012 © cybertrek 2012
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