A very small study has suggested that just six minutes of daily, high-intensity exercise might extend the brain's healthspan, and could delay the onset of neurodegenerative disorders like Alzheimer's and Parkinson's disease. Researchers were interested in whether the availability of a molecule called BDNF (brain-derived neurotrophic factor) could be increased in people, because BDNF availability has been linked with positive effects on brain health, learning and memory, and shielding the brain from cognitive decline in animal studies. BDNF also aids in the survival of neurons and neuroplasticity.
In a new study reported in The Journal of Physiology, researchers assessed the impact of various interventions: a 20-hour fast, a 90-minute session of light exercise, a six-minute session of high-intensity exercise, and a combination of fasting and exercise, in a group of 12 human volunteers. They wanted to see if there were affordable, accessible options for people that could promote healthy aging without the use of medication.
In animal models, BDNF has seemed to hold a lot of potential, but existing drugs have not been able "to safely harness the protective power of BDNF in humans," said lead study author Travis Gibbons from University of Otago. "We saw the need to explore non-pharmacological approaches that can preserve the brain's capacity [and] naturally increase BDNF to help with healthy aging."
This research indicated that the brief, high-intensity exercise session, which was vigorous cycling, was the most effective way for this small group of volunteers to increase their BDNF levels, compared to a day of fasting or light exercise. BDNF levels increased four to five times compared to fasting, which did not increase BDNF at all, or light exercise, which raised BDNF levels slightly.
More research would be needed to determine why these differences occur, and how they benefit people, as well as confirming the findings in a larger group. It may have to do with an increase in platelets, which store BDNF. Exercise has a dramatic impact on platelet levels compared to fasting. Another reason for the increase in BDNF levels after high-intensity exercise might be the transition from glucose to lactate metabolism that can occur in the brain during exercise.
The researchers are conducting additional research to differentiate between how fasting, exercise, and BDNF can impact cognition.
"We are now studying how fasting for longer durations, for example up to three days, influences BDNF. We are curious whether exercising hard at the start of a fast accelerates the beneficial effects of fasting; fasting and exercise are rarely studied together," noted Gibbons. "We think fasting and exercise can be used in conjunction to optimize BDNF production in the human brain."
Sources: The Physiological Society, The Journal of Physiology
