Fasting for 20 h does not affect exercise-induced increases in circulating BDNF in humans.
Travis D Gibbons1,2, James D Cotter1, Philip N Ainslie2
1School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.
The Journal of Physiology
|January 11, 2023
Summary
High-intensity exercise significantly boosts brain-derived neurotrophic factor (BDNF) levels more effectively than fasting or light exercise. This protein is crucial for neuroplasticity, learning, and memory, offering neuroprotection against cognitive decline.
Area of Science:
- Neuroscience
- Exercise Physiology
- Metabolic Health
Background:
- Intermittent fasting and exercise are known neuroprotective strategies against age-related cognitive decline.
- Both stressors can shift brain metabolism from glucose to alternative fuels, potentially upregulating brain-derived neurotrophic factor (BDNF).
- BDNF is vital for neuroplasticity, learning, and memory.
Purpose of the Study:
- To investigate the isolated and combined effects of fasting and different exercise intensities on peripheral BDNF levels.
- To explore the role of cerebrovascular shear stress in exercise-induced BDNF changes.
- To determine the most effective method for increasing circulating BDNF.
Main Methods:
- 12 human volunteers underwent 20-hour fasting, 90-minute light exercise, or high-intensity exercise intervals.
- Peripheral venous blood samples were analyzed for BDNF, glucose, ketones, lactate, and platelet counts.
- A follow-up study examined cerebrovascular shear stress effects on BDNF.
Main Results:
- Fasting (20h) increased ketones but did not affect BDNF levels.
- Light exercise (90 min) increased serum BDNF (6%) and platelets (7%), and plasma BDNF (336 to 390 pg/L).
- High-intensity exercise (6x40s intervals) increased plasma and serum BDNF, and BDNF-per-platelet ratio 4-5 fold more than light exercise; plasma BDNF correlated with lactate.
Conclusions:
- BDNF responses to low-intensity exercise are mediated by increased platelets.
- Increasing exercise intensity is crucial for liberating free BDNF.
- High-intensity exercise is a significantly more efficient strategy for increasing circulating BDNF compared to fasting or prolonged light exercise.
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