Protective Effects of Exercise on the Brain
As we know, we are living in an aging world. The Population Reference Bureau predicts that the number of Americans ages 65 or older is projected to double from almost 50 million to nearly 100 million in the next 40 years and this group will make up 24% of the total population of the United States at that time. As advancing age is associated with the development of dementia, these increases will bring challenges to patients, families and our health care system. As we have discussed before, exercise or physical activity is an important intervention in the prevention and treatment plans related to cognitive change. Addressing this issue, a recent article from the University of Calgary reviewed the protective effects of exercise on cognition and brain health.
In their article, Tyndall et al note that post maturation aging is accompanied by multiple adverse changes that contribute to cognitive decline. These include changes in biomarkers such as an increase in low-grade inflammation, increase in oxidative stress and a decrease in growth factors, such as growth hormone and neurotropic factors. Other changes include both psychological, mood changes, and physiological, such as a decrease in fitness and cerebrovascular function. Evidence suggests that physiologic changes, such as the decrease in cerebral blood flow, leads to hypoperfusion. Cerebral hypoperfusion is strongly linked to increased risk of cognitive dysfunction and dementia. In addition to these factors, lifestyle choices such as smoking, excessive alcohol use and poor diet contribute to overall brain health.
The beauty of our human design is that exercise or physical activity directly addresses these areas of change with aging. Exercise has been shown to decrease inflammation and oxidative stress while modulating neurotrophic factors. Related to psychological factors, multiple studies have shown improvement in mood, enhanced sleep and improvement in depression with exercise. During exercise, there is evidence of increased cerebral blood flow acutely and with chronic exercise, there is an improvement in hippocampal volume. When looking at cognition in older adults, studies show a direct relationship between cognitive abilities and higher VO2max. Emphasizing the importance of being a lifelong exerciser, there is interesting evidence that lower levels of cardiorespiratory fitness in early adulthood are related to a higher chance of cognitive impairment and dementia risk later in life.
Again, encouraging increased physical activity in everyone is an essential part of our roles as medical providers. We should encourage everyone to have an active day.
Tyndall, AV., et al. Protective effects of exercise on cognition and brain health in older adults. Exercise and Sports Science Reviews, 2018.
Nyberg J., et al. Cardiovascular and cognitive fitness at age 18 and risk of early onset dementia. Brain, 2014.