Written by Tara Garrison, certified personal trainer, nutritionist, and mindset coach
About the Author: Tara Garrison is the founder of HIGHER, a Health & Life Coaching company that offers training, nutrition, mindset and biohacking coaching. She has helped many celebrities, professional athletes, and top executives optimize their health. Tara is the author of Short-Term Keto, host of the Inside Out Health Podcast, creator of Higher Retreats and producer of the Coach Tara App. She is a mom of 4, avid weightlifter, Boston Marathoner and lover of nature.
How exactly exercise is such a mood booster? What happens chemically, inside of us, when we exercise?
- Endocannabinoids (also neurotransmitters but deserve their own discussion)
- And these incredible little things called called growth factors
When we exercise, we increase levels of all of the neurotransmitters that heavily impact our mood: dopamine, serotonin, noradrenaline, glutamate and GABA. (1,2)
How do these neurotransmitters impact how we feel?
When the brain has a healthy level of dopamine, our motivation increases and we become more productive. We plan well, learn quickly, and are excited about life. We are focused, attentive, creative, social and extroverted.
When dopamine levels are low, our motivation plummets, our mood drops, and we become more withdrawn.
Low dopamine levels can cause us to feel fatigued, restless, unmotivated, unfocused, depressed and anxious.
When serotonin is at normal levels, you feel happier, calmer, satisfied, optimistic, emotionally stable, less anxious and just in a generally good mood.
Serotonin also helps regulate appetite, your sleep-wake cycle, helps you think more clearly and has an impact on sexual desire.
It also impacts a wide variety of physiological systems, such as cardiovascular regulation, respiration, and thermoregulation.
Noradrenaline, also called norepinephrine, increases alertness, arousal and attention. At healthy levels, it lead to a feeling of euphoria. It speeds up your heart, which also increases the amount of blood pumping from your heart, which increases oxygenation of the brain and body.
Glutamate & GABA:
Glutamate is important for memory, cognition and mood regulation.
GABA helps you feel cool, calm and collected; you’re not overly worried about things.
These 2 neurotransmitters are inseparably connected- glutamate converts into GABA. We need this conversion to happen in a healthy way, since too much glutamate can cause us to become anxious and restless.
Too much glutamate in the brain can also cause nerve cells to become overexcited, which can lead to cell death. We definitely want glutamate at healthy levels so we have healthy brain function, and we also want it to convert into GABA so it doesn’t goo too high.
This is where exercise helps.
The conversion of glutamate into GABA happens almost entirely in the gut, and research shows that exercise has a positive impact on the gut microbiome, creating a healthier environment for this conversion to happen. (3) Exercise also increases blood flow to the muscles in the digestive system, which helps food move along so we maintain a healthy microbiome.
So, from a neurotransmitter standpoint alone, exercise increases:
- Emotional stability
I mean… sheesh. But wait! There’s more…
These are actually neurotransmitters, too, but they’re so unique and newly discovered, that they deserved a category of their own.
Did you know your body has an Endocannabinoid System?
“Endo-“ means “within,” and in human physiology often refers to things that are naturally made inside the body. So yes, this is exactly as it sounds: your body makes its own cannabinoids.
Turns out cannabis isn’t the only way to get high.
The first endocannabinoid, anandamide, was only discovered in 1992; and what a discovery it was.
Shortly before, in 1988, researchers at St. Louis University School of medicine were conducting a government-controlled study exploring THC (Tetrahydrocannobinol), a well-known cannabinoid in cannabis (the one that makes you “high”) when they found that we have cannabinoid receptors that respond to cannabis and that these cannabinoid receptors are the most prevalent type of neurotransmitter receptor in the brain!
Let me say that again: you have more receptors for cannabinoids in your brain than for any other neurotransmitter.
The two main endocannabinoids that have been identified include anandamide and 2-archidonoyl glycerol (2-AG). Scientists believe there are additional endocannabinoids in the body but they are not fully understood yet.
And you’ve probably already guessed it, but guess what boosted endocannabinoid levels across studies?
The effects were most consistent for anandamide, now nicknamed the “bliss” molecule, because of its positive effects on mood. The name itself comes from the Sanskrit word “ananda,” which means “happiness, pleasure, joy, and delight.” So if you’re wondering what anandamide feels like, there you go.
Some experts are now suggesting that the “runners’ high” once attributed exclusively to the more well-known neurotransmitters we discussed above, may be largely due to an increase in anandamide.
A meta-analysis of 33 published studies on the impact of exercise on endocannabinoid levels found that acute exercise consistently boosted endocannabinoid levels across studies. (4)
They saw this boost in endocannabinoids across all different types of exercise, including running, swimming and weightlifting, and across individuals with and without preexisting health conditions.
It did appear that moderate levels of exercise intensity were more effective at raising endocannabinoid levels than lower-intensity exercise such as walking.
Last, what does anandamide do besides provide a feeling of bliss? It also plays a role in memory, appetite, sleep and pain relief.
And it’s all yours, made right inside your own body, any time you exercise.
Growth factors are exactly what they sound like— they help your body grow.
You want your body to be growing. If you’re not growing, or in adulthood we could call it renewing, you’re dying. So especially in adulthood, we want to be proactive about creating an environment in our bodies that leads to growth and renewal. We want to be proactive about supporting the release of growth factors in our bodies.
And how do we do that? Yep. Exercise.
Exercise increases two incredibly important growth factors:
Insulin-Like Growth Factor-1 (IGF-1)
and Brain-Derived Neurotrophic Factor (BDNF)
What do these growth factors do in the body?
IGF-1 is the active growth hormone in your body. When growth hormone (GH) is released, it stimulates IGF-1 production mainly in the liver, and also in other locations such as your muscles, heart, adipose tissue, brain and pancreas. IGF-1 from the liver circulates in your bloodstream to help regenerate cells throughout the body.
BDNF helps the brain develop new connections (neuroplasticity), repair failing brain cells (neuroregeneration), and protect healthy brain cells (neuroprotection).
If you want a healthy brain and nervous system, you want BDNF.
And if you want your muscles, bones, and organs to regenerate healthily, you want IGF-1.
How do you get more IGF-1 and BDNF?
For healthy levels of both of these growth factors, exercise is the name of the game.
For IGF-1, resistance training raises levels the most. (4)
How does it do this?
It’s important to understand that you have a growth hormone “axis” just like many other systems of the body. For your stress response, you have a HPA axis - hypothalamic-pituitary-adrenal axis. For your metabolism, you have a HPT axis- hypothalamic-pituitary-thyroid axis. For men’s fertility, you have a HPG axis- hypothalamic-pituitary-gonadal axis. For women’s fertility, you have a HPO axis- hypothalamic-pituitary-ovarian axis.
The list goes on.
For growth, you have an IGF axis, short for Growth Hormone/IGF-1 axis.
While I’m oversimplifying the variety of functions each of these axes plays, it’s important to understand that your body has a feedback loop that informs your pituitary gland in your brain to secrete hormones that kick off certain processes in the body.
And where does your pituitary gland get its information? From your body.
Your actions, your environment, and even your thoughts- they all signal to the brain what your body needs.
When we engage in resistance training, we signal to our brain that we are going to need growth factors to help recover our muscles from the workout and also help the body adapt to the increased muscular demands being placed on it.
Resistance training is a powerful way to boost IGF-1.
One important note on that for beginners:
Researchers found that when test subjects first began a training program, the stress created pro-inflammatory cytokines and a decrease in circulating IGF-1. However, with longer commitment to the training program, pro-inflammatory cytokines dropped and both GH and IGF-1 levels exceeded their pre-training level. (5)
So the moral of the story is: stick with it.
For BDNF, resistance training, high intensity interval training and aerobic exercise have all been shown to boost BDNF, although intensity appears to be the name of the game overall for boosting BDNF.
A study on college-age males showed a huge increase in BDNF from weightlifting. Immediately post-training, BDNF was almost 3 times the resting values, and it continued to go up 30 minutes post-training, and leveled off (though still elevated) 60 minutes post training. (6)
In regards to resistance training approaches and BDNF production, a study involving untrained males and females showed hypertrophy-focused resistance training resulted in significantly greater BDNF levels when compared with strength exercises (7).
In regards to high intensity interval training, one study made an interesting observation. It appears that the more body fat a person has, and while they are going through a reduction in body fat, the less BDNF will be boosted through exercise (they tested high intensity exercise in this study), and can even drop in response to exercise. (8) The healthier the body composition a person had, the greater the BDNF increased in response to training. So similar to IGF-1, it appears good things come with time, so stay consistent.
In regards to aerobic exercise, one study showed a 32% increase in serum BDNF levels in response to aerobic exercise. Furthermore, it showed vigorous intensity (80% heart rate reserve) and long duration (40 minutes) offered the greatest probability of a significant BDNF elevation. (9)
If you want a healthy brain that allows you to make new connections, repair unhealthy cells and protect healthy brain cells, exercise.
If you want to regularly release the “bliss molecule” into your system, exercise.
And if you want to regularly release every neurotransmitter that gives you a better mood and better life, exercise.
1. Tzu-Wei Lin, Yu-Min Kuo. “Exercise Benefits Brain Function: The Monoamine Connection,” Brain Sci, doi: 10.3390/brainsci3010039
2. R. J. Maddock, G. A. Casazza, D. H. Fernandez, M. I. Maddock. Acute Modulation of Cortical Glutamate and GABA Content by Physical Activity. Journal of Neuroscience, 2016; 36 (8): 2449 DOI: 10.1523/JNEUROSCI.3455-15.2016
3. Vincenzo Monda, Ines Villano, Antonietta Messina, Anna Valenzano, Teresa Esposito, Fiorenzo Moscatelli, Andrea Viggiano, Giuseppe Cibelli, Sergio Chieffi, Marcellino Monda, and Giovanni Messina. “Exercise Modifies the Gut Microbiota with Positive Health Effects.” Oxidative Medicine and Cellular Longevity, 2017. doi: 10.1155/2017/3831972
4. Angelica Miki Stein, Thays Martins Vital Silva, Flavia Gomes de Melo Coelho, Franciel Jose Arantes, Jose Luiz Riani Costa, Elizabeth Teodoro, Ruth Ferreira Santos-Galduroz. "Physical Exercise, IGF-1 and cognition: A systematic review of experimental studies in the elderly." Dementia & Neuropschologia, 2018; doi: 10.1590/1980-57642018dn12-020003
5. Alon Eliakim, Dan Nemet. “Exercise training, physical fitness and the growth hormone-insulin-like growth factor-1 axis and cytokine balance.” Med Sport Sci. 2010; doi: 10.1159/000321977
6. David D Church, Jay R Hoffman, Gerald T Mangine, Adam R Jajtner, Jeremy R Townsend, Kyle S Beyer, Ran Wang, Michael B La Monica, David H Fukuda, Jeffrey R Stout. “Comparison of high-intensity vs. high-volume resistance training on the BDNF response to exercise.” Journal of Applied Physiology, 2016. doi: 10.1152/japplphysiol.00233.2016
7. Kieran J Marston, Michael J Newton, Belinda M Brown, Stephanie R Rainey-Smith, Sabine Bird, Ralph N Martins, Jeremiah J Peiffer. “Intense resistance exercise increases peripheral brain-derived neurotrophic factor.” J Sci Med Sport, 2017; 20 (10). doi: 10.1016/j.jsams.2017.03.015
8. Eugenia Murawska-Ciałowicz, Gilmara Gomes de Assis, Filipe Manuel Clemente, Yuri Feito, Petr Stastny, Jolanta Zuwała-Jagiełło, Bartosz Bibrowicz & Paweł Wolański. “Effect of four different forms of high intensity training on BDNF response to Wingate and Graded Exercise Test.” Nature, 2021. Article number: 8599 (2021)
9. Matthew T. Schmolesky, David L. Webb, and Rodney A. Hansen. “The Effects of Aerobic Exercise Intensity and Duration on Levels of Brain-Derived Neurotrophic Factor in Healthy Men.” J Sports Sci Med, 2013 Sep. PMCID: PMC3772595