The neurophysiology behind exercise

What happens when we exercise?

Primarily when we exercise blood flow increases around our body. This occurs in the areas of the body that we are using as oxygen is required to break down glucose and create the fuel that is used by our muscles to contract – adenosine triphosphate (or ATP). As all bodily functions require a neurological component, during exercise there is also a significant increase in blood supply to the brain [4].

Due to this increased blood flow to the brain, neurophysiology and neuroplasticity involved with movement, exercise has been shown to have a positive effect on mood, cognition memory, anxiety, depression, sleep and even decreasing risk for dementia [1, 5].

So how does this happen?

When we exercise this elicits an acute stress response. The amygdala (attributed to emotional processing) sends a signal to the hypothalamus (the command centre of the brain) which communicates to the autonomic nervous system. Our autonomic nervous system is divided into our sympathetic nervous system and our parasympathetic nervous system [6]. With an acute bout of exercise (i.e., running 5km a single time) our sympathetic nervous system (fight-flight response) stimulates epinephrine (commonly known as adrenaline) to course through the body causing multiple physical changes including our heart rate and respiratory rate to rise, delivering more blood to the body due to increased oxygen demand [7]. This is an extremely quick reaction, and to maintain this sympathetic nervous system response cortisol is released to keep the body revved up and alert. Cortisol is what is often referred to as our stress hormone, but also in an acute form it also increases happiness, memory, and lower sensitivity to pain.

This is an acute stress system and is extremely beneficial and important for our bodies and our brains. Like any acute situation it should pass, and then the parasympathetic nervous system becomes more involved to return to metabolic and physical regulation.

Ample evidence outlines that chronic bout of exercise (i.e., repeated running over multiple times) improves the regulatory effect of the parasympathetic nervous system (rest and digest, the brake), increasing parasympathetic outflow and the increased ability to control and temper the sympathetic nervous system [8]. This results in a decrease in resting heart rate, improved regulation of blood pressure, and improved regulation of the cortisol – therefore improving many parameters associated with increased physical and mental health risk [8].

Social benefits

Through this blog we have covered what is happening physically to the body and brain during exercise and the evidence behind it. What we have not touched upon is the social effect of being involved with exercise or the mindfulness/focused elements of exercise. These elements are also known to be positively affected by both acute and chronic bouts of exercise in multiple population groups which we discuss further in future blogs.

So how can I make exercise a regular habit?

What is the most important thing with exercise is developing a long-term habit. You can have the most amazing programme given to you, but if that doesn’t fit with you are, your goals, your likes and dislikes, then it is unlikely it will be done.

A few tips that are important for everyone;

1. Find something that you like to do – we cannot overstate how important this is. It needs to make you happy 😊
2. Slow and steady wins the race – its about the long game, the healthy game
3. SMART goals – Specific, Measurable, Attainable, Relevant, Time-bound: it keep your eyes on the prize and keep you engaged SMART goal setting can be extremely effective.
4. Progressive overload – Like all good things in life we need to keep things challenging to keep it adapting.
5. Find something you like to do.
6. Make it social (involve friends or family)
7. Consider it as an INVESTMENT into the future

References

1. Wang, Y. and K. Ashokan, Physical Exercise: An Overview of Benefits From Psychological Level to Genetics and Beyond. Front Physiol, 2021. 12: p. 731858.
2. Geneen, L.J., et al., Physical activity and exercise for chronic pain in adults: an overview of Cochrane Reviews. Cochrane Database Syst Rev, 2017. 4: p. Cd011279.
3. Ruegsegger, G.N. and F.W. Booth, Health Benefits of Exercise. Cold Spring Harb Perspect Med, 2018. 8(7).
4. Delp, M.D., et al., Exercise increases blood flow to locomotor, vestibular, cardiorespiratory and visual regions of the brain in miniature swine. J Physiol, 2001. 533(Pt 3): p. 849-59.
5. Wang, S., et al., Exercise Dosage in Reducing the Risk of Dementia Development: Mode, Duration, and Intensity-A Narrative Review. Int J Environ Res Public Health, 2021. 18(24).
6. Waxenbaum, J.A., V. Reddy, and M. Varacallo. Anatomy, Autonomic Nervous System. 2022  [cited 2022 28.11.2022]; Available from: https://www.ncbi.nlm.nih.gov/books/NBK539845/.
7. Basso, J.C. and W.A. Suzuki, The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review. Brain Plasticity, 2017. 2: p. 127-152.
8. Morgan, J.A., F. Corrigan, and B.T. Baune, Effects of physical exercise on central nervous system functions: a review of brain region specific adaptations. J Mol Psychiatry, 2015. 3(1): p. 3.
9. Vecchio, L.M., et al., The Neuroprotective Effects of Exercise: Maintaining a Healthy Brain Throughout Aging. Brain Plast, 2018. 4(1): p. 17-52.

Author: Katina McCulloch
Co-founder and director at Waves

Disclaimer:

This site cannot and doesn’t contain medical/health advice. The medical/health information is provided for general informational and educational purposes only and is not a substitute for professional advice. Accordingly, before taking any actions based upon such information, we encourage you to consult with the appropriate professionals.