- People have said for awhile that exercise is good for the brain. That’s a pretty broad statement and is usually associated with anecdotal evidence. In the Journal of Applied Physiology, Church et al have an interesting study looking at strength training and something called brain-derived neurotrophic factor (BDNF).
BDNF is a protein that supports the survival of neurons in the nervous system, as well as growth and differentiation of new neurons. It is important for memory, neurogenesis (growing new neurons), and helps with learning. There have been a number of studies on endurance exercise that show that it increases BDNF.
In their study, the authors studies 20 college-aged resistance trained males. Subjects trained four times a week for a two week preparatory phase and then an eight week training intervention. Subjects were divided into one of two groups for the eight week intervention; either a high volume group (4×10-12×70% with 60 seconds rest between sets) or a high intensity group (4×3-5×90% with 180 seconds rest between sets). Both groups did a program centered around squats, deadlifts, bench press, and other fundamental barbell exercises.
Blood samples were collected after the first exercise session of the study and after the first exercises session of week eight.
Results:
- When looking at the blood samples from the first exercise session (i.e. after that exercise session), BDNF concentrations increased drastically after the exercise session. Immediately post-exercise it was almost 3 times the resting values, it continued to go up 30 minutes post-exercise and leveled off (though still elevated) 60 minutes post exercise.
- This pattern continued after eight weeks of training, but the baseline concentrations and the concentrations reached at each time marker were greater than during the first exercise session.
- The training approach (i.e. high intensity vs. high volume) did not impact BDNF levels.
In college-aged males, strength training increases the concentrations of BDNF. There are a few thoughts with this. First, the focus on fundamental barbell exercises (squats, deadlifts, bent-over rows, bench press, etc.) means that the most motor units are being recruited during the exercises. In other words, these are more taxing exercises for the nervous system than (for example) concentration curls or leg extensions. With this in mind, it makes sense that this type of exercise would require the body to maintain/develop neuronal pathways to support the exercise.
Interesting things to think about (but also things that we cannot answer from the study). First, are any effects from BDNF specific to the exercise? In other words, does it build/maintain neuronal pathways for the parts of the nervous system performing the squat? Or, is there a more general effect (i.e., could squatting improve your memory?). Second, if there are indeed neuronal effects, are these transferable to tasks like sprinting, jumping, throwing, etc.?
Great study, I love learning new things. I had literally never heard of this before I read the article in the Journal of Applied Physiology.
Church, D.D., Hoffman, J.R., Manguine, G.T., Jajtner, A.R., Townsend, J.R., Beyer, K.S., Wang, R., La Monica, M.B., Fukuda, D.H., and Stout, J.R. (2016). Comparison of high-intensity vs. high-volume resistance training on the BDNF response to exercise. Journal of Applied Physiology, 121, 123-128.
