A warm glow of relaxation comes over the body as the clock ticks and the body is enveloped by the heat of the sauna. Saunas are almost synonymous with relaxation, and high-end spas around the world have used them for decades. The bio-mechanics behind the soothing sensations that are offered through a sauna experience all begin with the body’s nervous system.
The nervous system is truly a wonder to behold as it gracefully dances between the external environment and the internal landscape of both the mind and body. When passive heat is introduced to this dance, magical occurrences begin to happen in the body to promote physical vitality and clarity of the mind.
An indepth examination into the full expression of the nervous system is necessary to understand the sense of relaxation that comes over the body during and after a sauna session. Relaxation is often considered a luxury in our fast paced world of productivity and long work hours. The reality is that relaxation is the primordial state of being necessary for healing to occur.
Many autoimmune disorders, longterm diseases, heart conditions, and so many more ailments find their root cause in a dysregulated nervous system. Some experts have posited that all health and well being begins and ends with the nervous system.
Explore the functions of the nervous system and how the passive heat from a sauna session can delicately bring balance and harmony back to the nervous system.
What is the Nervous System?
The nervous system has two primary and distinct expressions: The central nervous system and the peripheral nervous system. (1) Both portions of the nervous system are in constant communication with the outside world as well as with each other.
The nervous system is an intricate web of neurons that move collectively throughout the body and are connected by synapse. (1) All of the neurons in your body begin and end their journey in your brain or spine. The central nervous system is exactly what it sounds like, it is central in your body- meaning it operates from the brain down the mid-line of your body through the spine; while the peripheral nervous system connects the central nervous system to the rest of the body. (1)
What you see, smell, hear, feel, and even taste/ingest are all interpreted and communicated by the nervous system. The nervous system appears as an intricate tree with many branches and roots all interlinking in a mystic fashion.
The peripheral nervous system comprises the autonomic nervous system (ANS), and this is where the treasure of sauna use can be so wildly impactful. As is indicated by its name, the autonomic nervous system regulates the involuntary actions in the body such as heart rate, respiration, digestion, and blood pressure. (2)
Many individuals have heard that the autonomic nervous system is divided into two primary branches called sympathetic dominance and parasympathetic dominance, or division. In reality there are three divisions of the ANS. The lesser known enteric sector of the ANS is described below by the author of this article ‘Enteric Nervous System’ (3) of the peer reviewed journal Science Direct.
“The enteric nervous system is one of the three divisions of the autonomic nervous system, the others being the sympathetic and parasympathetic. In contrast to the other divisions, it can perform many functions independently of the central nervous system.” (3)
To understand how saunas can impact the autonomic nervous system the focus will be on the two portions of the ANS called the sympathetic and parasympathetic divisions.
Have you ever felt anxious and not known why, or had a feeling of excitement, without any cognitive input? Well, many of these ‘feelings’, ‘or hunches’ can be explained by the ANS. The National Library of Medicine has published an article entitled ‘Anatomy, Autonomic Nervous System’ (2) and here the authors write about this ‘knowingness’, or ‘gut feeling’ in this statement.
“Feedback from the ANS is usually processed at a subconscious level to produce reflex actions in the visceral or somatic portions of the body.” (2)
Why is this important for relaxation, and how does this connect to sauna use? The reality is that most individuals are operating in prolonged states of sympathetic dominance (stress/fight/flight/freeze), without even knowing it necessarily. It may just be that over time falling asleep becomes more difficult, or perhaps you find that you are more on edge for no apparent reason. Or, perhaps there exists a low grade level of anxiety settled into your gut space. All of this occurs because your ANS is picking up on things in your external or internal environment that are perceived to be threatening, or are already threatening your safety and well being.
It may be the case for some individuals that this ongoing stress is not invisible at all, but rather has already taken form as an auto-immune disorder, or some form of heart disease, or chronic insomnia.
While there are many ways that toxic ongoing stress can build up in an individual’s life, such as long commutes, environmental toxins, relational stress, over work, financial hardship, loss of a loved one, heart break, and so much more, there is still hope to repair and rebalance the ANS. This can be done by spending increasing amounts of time in the parasympathetic branch of the ANS.
The parasympathetic division of the nervous system is crucial because it provides the body with a place of relaxation where energy can be directed inward toward healing instead of outward into activity. Many individuals have difficulty exiting states of sympathetic dominance and coming back home to a place of parasympathetic dominance where sleep comes easily, wounds are healed, and the mind is peaceful.
This means that to truly heal the nervous system there needs to be a variety of tools available for individuals to help them relax and find harmony within. The means by which an individual opens the door from sympathetic dominance to parasympathetic dominance are many. From yoga, meditation, boating, massage, long walks, deep breaths, spending time with loved ones, and so on, making time for these activities is crucial for your health. A very fast and effective way of bringing the body into states of relaxation is the use of passive heat, namely in a sauna, hot tub, or even a hot bath.
Find out what mechanisms within the body are affected by passive heat to draw the ANS out of states of stress response back into states of deep relaxation.
How Does the Heat From a Sauna Session Relax the Body?
Nestling into the sauna can sometimes feel like going back into the safety of the womb. The heat from a sauna initially triggers a heat stress response in the body by raising the heart rate to engage the cardiovascular system to begin the perspiration response. None of this sounds particularly relaxing; however, just after the initial surge of hormonal activity in response to the high heat is where the pivot point occurs in the sauna and what follows is the body relaxing into a pool of ‘feel good’ hormones.
According to a publication from Science Direct entitled ‘Endocrine effects of sauna bath’ (4) once the body moves through that initial stage of discomfort in the sauna right before the production of perspiration and into the rest of the sauna session many hormones that help to make the body and mind feel soothed come flooding in.
“When the heat exposure reaches the level of subjective discomfort, the ACTH/β-endorphin increase is more consistent. The increase in β-endorphin may play a role in the feeling of well-being after sauna.” (4)
For the remainder of a sauna session the body is filled with endorphins of different varieties that help the individual’s mood to feel both soothed and enhanced. This is one signal, ‘data entry’ that the ANS receives to help it begin its transition into a state of relaxation.
In addition to the positive hormonal influx induced from passive heat in the sauna, the increased circulation causes blood pressure to lower which is another indication, ‘data entry’ to the ANS to transfer out of states of stress response. Dr. Adolph Hutter, professor of medicine at Harvard Medical School writes this regarding saunas and blood pressure.
“The high temperatures in a warm tub or sauna cause your blood vessels to dilate, which lowers blood pressure.” (5)
The marriage of positive hormones released after sweating has begun in the sauna and the lowering of blood pressure are both positive inputs that signal to the ANS subconsciously to draw the body out of states of sympathetic dominance back into states of relaxation in the body.
Another, less researched aspect of relaxation in the sauna is the lack of sensory overload. When an individual chooses to take a sauna there are several actions that arise:
- A choice to take time out of your day just for you
- A lack of interference from the outside world
- A change in atmospheric lighting and sound
- An overall lack of sensory input
All four of these factors aid the body into states of parasympathetic dominance by signalling the ANS that it is safe in the outside world. As was discussed earlier, the nervous system is in constant communication with the outside world via the five physical senses. In a sauna there are far less stimuli than in most other situations in life. This lack of sensual stimulation may signal to the ANS subconsciously that all is safe in the world and that the body can now begin to move fully into states of relaxation.
Once relaxation can be found and sustained true healing of the body begins naturally and subconsciously.
The sauna experience presents a cocktail of positive input to the nervous system via hormones, lowered blood pressure, and dilution of sensory absorption to easily guide individuals out of states of stress response and back into states of relaxation and healing.
Relax Your Way to Health and Wellness With Regular Sauna Sessions
It has long been known that saunas have the capacity to induce relaxation in its users. Now science, for the most part, can explain in detail how the experience of passive heat affects the autonomic nervous system to draw it back into states of deep relaxation.
Furthermore, it is now understood that relaxation is not a luxury to be experienced a few times a year on vacation, but rather a state of being that is necessary for health. In addition, a lack of relaxation on a regular basis ultimately can lead to serious long term illness.
Take time for yourself using a variety of tools, perhaps even sauna sessions to actively draw your ANS out of states of chronic, toxic stress, and back into states of relaxation to maintain health, and even prevent serious disease.
Saunas are a powerful means to ride the train home to parasympathetic dominance and balance the entire nervous system via hormonal, environmental, and lowered blood pressure input. It may not be possible, or even valuable to escape high stress situations, but it is possible to actively induce states relaxation without using pharmaceuticals.
The use of saunas may not be for everybody. Consider your own physical state and talk to your medical practitioner before beginning your sauna bathing protocol. If you do use saunas regularly, or are planning to, please ensure that you maintain excellent hydration, and be mindful of electrolyte consumption to adapt to the high levels of perspiration.
Sources Cited:
- https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/treating-repairing-nervous-system
- https://www.ncbi.nlm.nih.gov/books/NBK539845/
- https://www.sciencedirect.com/topics/neuroscience/enteric-nervous-system
- https://www.sciencedirect.com/science/article/abs/pii/S2451965019301048
- https://www.health.harvard.edu/heart-health/hot-baths-and-saunas-beneficial-for-your-heart