In Episode 2, we use BDNF, Brain Derived Neurotrophic Factor, as a real biological example of how training and environment shape adaptation. BDNF is part of the neurotrophin family, signals that support neurons and plasticity, which matters for learning, mood, and performance. We walk through the research history behind neurotrophins, including the NGF thread, and then bring it into modern exercise science. We cover what studies tend to show about acute exercise effects on peripheral BDNF, what longer training programs suggest about resting peripheral BDNF, and a measurement nuance that changes how results appear, serum versus plasma, and why platelets matter.

The episode closes by connecting BDNF signaling to the real world plateau problem. A lot of the time it is not that the plan is wrong on paper. It is that the recovery environment is unstable. We talk about why sleep timing and stress load shift the background physiology that training signals land inside of, and why that changes whether progress “sticks.”

Your biology listens. Live like it.

Key Terms

BDNF: Brain Derived Neurotrophic Factor. A neurotrophin involved in neuronal support and plasticity.

Neuron: A nerve cell that transmits signals in the brain and nervous system.

Neurotrophin: A family of proteins that support neuron survival and plasticity, includes NGF and BDNF.

NGF: Nerve Growth Factor. A protein that supports survival and growth of certain neurons, important in the research history of neurotrophic signaling.

Purification: Laboratory isolation of a molecule from tissue so it can be studied directly.

Microgram: One millionth of a gram.

Peripheral BDNF: BDNF measured outside the brain, typically in blood.

Serum: The liquid part of blood after clotting.

Plasma: The liquid part of blood when clotting is prevented.

Platelets: Blood components involved in clotting that can store and release proteins like BDNF during sample processing.

TrkB: A high affinity receptor for BDNF, often discussed as a main docking site for BDNF signaling.

Receptor: A cellular docking station that receives a signal and triggers internal responses.

Plasticity: The ability of the nervous system to strengthen connections and improve function through learning and repetition.

Adaptation: A lasting biological change after repeated training signals, where the body becomes better at handling the same demand.

Physiology: How the body functions in real time, including hormones, nerves, muscles, and recovery systems.

Anabolic: A metabolic direction that supports building and repair.

Catabolic: A metabolic direction that supports breakdown or conservation.

Muscle protein synthesis: The process of building and repairing muscle tissue from amino acids.

References

Barde YA, Edgar D, Thoenen H. Purification of a new neurotrophic factor from mammalian brain. The EMBO Journal. 1982.

Dinoff A, Herrmann N, Swardfager W, Liu CS, Sherman C, et al. The Effect of Exercise Training on Resting Concentrations of Peripheral Brain Derived Neurotrophic Factor (BDNF): A Meta Analysis. PLOS ONE. 2016.

Serra Millàs M. Are the changes in the peripheral brain derived neurotrophic factor levels due to platelet activation. World Journal of Psychiatry. 2016.

Lamon S, Morabito A, Arentson Lindgren M, et al. Acute sleep deprivation and anabolic resistance in skeletal muscle, with related hormonal environment changes. Physiological Reports. 2021.

The Nobel Prize in Physiology or Medicine 1986 Press Release. NobelPrize.org. Background context on NGF and growth factor history.