Beyond physical fitness: how exercise can boost brain health

Considerable evidence has supported the cognitive benefits of exercise, including improvements in brain function and behavior, as well as decreasing the burden of neuropsychiatric disease. And, the benefits may last a lot longer than anyone previously thought, extending into future generations via epigenetic changes, according to the authors of an article published in Neuroscience & Biobehavioral Reviews.

Keeping in mind the exciting possibility that exercise done today may benefit posterity, here is some reinforcement for the cognitive benefits of exercise.

Brain plasticity

Neural plasticity refers to the ability of the brain to change and adapt over time in response to experience. Results from an experimental study published in Brain, Behavior, and Immunity demonstrated increased neural plasticity in older adults related to exercise, as measured by blood levels of brain-derived neurotrophic factor (BDNF), insulin-like growth factor type 1 (IGF-1), and vascular endothelial growth factor (VEGF)—which are putative markers of exercise-induced cognitive benefits.  

“This study demonstrates the first link between exercise-related changes in functional connectivity in the temporal cortex and changes in three putative neurobiological mechanisms for exercise-induced benefits on brain function, including BDNF, IGF-1, and VEGF,” the authors wrote. 

“These results lend credibility to the low frequency BOLD signal as reflective of neuronal processes, and suggest that aerobic exercise-related increases in circulating growth factors are related to temporal lobe functional brain connectivity in elderly humans,” they concluded.

Depression and anxiety

Plenty of research has focused on the benefits of exercise in curbing depression and anxiety. Regular exercisers are less depressed and anxious than those who are sedentary, suggesting that exercise may serve as treatment for the disease, according to a review published in Frontiers in Psychology.

“Most of the research on the relationship between PE [physical exercise] and positive changes in mood state has evidenced positive effects,” they wrote, “especially as a consequence of aerobic exercise, regardless of the specific type of activity, even if the correct intensity of aerobic PE to control and reduce symptoms is debated.”

They also noted that “anaerobic activity has positive effects on treatment of clinical depression. For anxiety disorders, it has been evidenced that the positive effects of PE are visible even with short bursts of exercise, independently from the nature of the exercise.”

As for a mechanism, the authors noted that it could involve the modulation of peripheral levels of BDNF, with lower levels observed in those with major depressive or bipolar disorder. High-intensity exercise in particular could lower oxidative stress levels and improve mood. 

The authors recommended that exercise at the patient’s preferred intensity should be prescribed to enhance mood.

Unhealthy behaviors

The literature supports the ability for exercise to help curb the misuse of substances such as alcohol or tobacco, as well as unhealthy behaviors, including problem gambling and overeating, according to the aforementioned review. The authors noted that a few days of exercise can boost oxygenation to the prefrontal cortex, improving mental health.

Ironically in some, “exercise addiction” has been noted, which manifests as withdrawal symptoms after 24 to 36 hours of no exercise, including anxiety, nervousness, guilt, irritability, muscle twitching, and feelings of bloat.

The authors wrote, “There is a strong correlation between exercise addiction and eating disorders suggesting thus a comorbidity of these disorders and a common biological substrate. In particular, recent studies have shown that these unhealthy behaviors are associated [with] lower prefrontal cortex volume, activity and oxygenation, with consequent impairment in cognitive functions, such as the inhibitory control with the consequent compulsive behaviors.”

Memory

Clinical research cited and supported by the NIH showed that 10 minutes of low-intensity exercise in the form of light pedaling on a stationary bike enhanced brain activity of the hippocampus, a structure key in remembering facts and events. Other quick, light workouts that could provide similar benefit include a short yoga or tai chi session.

“Brain scans of the participants after the light exercise also revealed stronger connections between the hippocampus and cerebral cortex, which plays an important role in detailed memory processing,” wrote NIH director Francis Collins, MD, PhD. “What’s more, the level of heightened connectivity in a person’s brain after exercise predicted the degree of their memory improvement.”

Alzheimer disease

Alzheimer disease is a neurodegenerative illness, caused by the accumulation of β-amyloid plaques and neurofibrillary tangles at the cerebral level and other pathophysiologic insults that occur on a holistic level. Exercise may enhance brain plasticity, boost adrenal sensitivity, enhance vascular health, and improve nitric oxide bioavailability and mitochondrial function, according to the results of a systematic review published in Current Alzheimer Research.

The authors concluded, “Knowing that disturbances in brain, neuroendocrine, vascular and mitochondria metabolism are important events in neurodegeneration and dementia development, the ability of exercise to trigger adaptive mechanisms might represent an important non-pharmacological strategy to improve resilience to AD [Alzheimer disease].”