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High-Intensity Exercise May Protect Against Cognitive Decline
High-intensity exercise intervals of 6 minutes could protect the brain from age-related cognitive decline and the onset of Alzheimer disease by increasing the production of brain-derived neurotrophic factor (BDNF), according to study findings published online ahead of print in The Journal of Physiology.
BDNF is a specialized protein that promotes neuroplasticity and neuron survival. In studies of animals, increasing the availability of BDNF enhanced learning and boosted cognitive performance, the research team explained.
“BDNF has shown great promise in animal models, but pharmaceutical interventions have thus far failed to safely harness the protective power of BDNF in humans,” said study lead and corresponding author Travis Gibbons, MSc, a PhD candidate at the University of Otago, New Zealand. “We saw the need to explore nonpharmacological approaches that can preserve the brain’s capacity, which humans can use to naturally increase BDNF to help with healthy aging.”
>>READ: Higher Activity Levels Linked to Lower Dementia Risk
The study compared the effects of fasting for 20 hours, low-intensity cycling for 90 minutes (prolonged, light exercise), vigorous cycling for 6 minutes (high-intensity exercise), and combined fasting and exercising in 12 physically active adults, ages 18 through 56. Half were women.
Brief, high-intensity exercise was the most efficient way to increase BDNF, according to the study. BDNF increased 4- to 5-fold more with six 40-second high-intensity intervals compared with fasting or prolonged, light exercise.
Although more research is needed to understand the mechanisms involved, the research team provided several hypotheses. One involved the cerebral substrate switch, or when the brain changes its fuel source to ensure the body’s energy demands are met, such as metabolizing lactate instead of glucose during exercise. The transition from the brain’s consuming glucose to lactate initiates pathways that result in elevated BDNF levels in the blood, they explained.
Another possibility is an increased number of platelets, which store larger amounts of BDNF, with exercise. According to the team, exercise has more of an influence on the concentration of platelets circulating in the blood than fasting.
“We are now studying how fasting for longer durations, for example up to 3 days, influences BDNF. We are curious whether exercising hard at the start of a fast accelerates the beneficial effects of fasting,” Gibbons said. “Fasting and exercise are rarely studied together. We think fasting and exercise can be used in conjunction to optimize BDNF production in the human brain.”
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