Four studies that provide interesting conclusions about negative ions in the sauna

Guest post series continues. We are pleased to introduce Daniel Stroberger who will be bringing forth some technical insight regarding sauna. Daniel’s background and introduction is below. We have received several inquires about negative ions relative to the authentic sauna experience. Daniel brings us an in depth analysis of the existing research and some interesting observations for those of us interested in the topic of negative ions and sauna. Enter Daniel:

I find the topic of negative ions and health implications very interesting. It is a unique intersection of physics, chemistry, biology, and psychology.  

Pouring water on hot sauna rocks causes shearing during the creation of steam which can generate negative ions via the Lenard effect. The life of water-generated negative ions is longer in the air than electrically generated negative ions via corona discharge.  

When negative ions exist for a longer time in an enclosed space there is increased opportunity for interaction with the human body before the negative ions interact with a positive ion and become neutralized.

Wood is considered an insulator and by proxy carries a neutral electrical charge. Sauna interiors are mostly constructed of wood, so this could further promote the life of negative ions generated in a sauna environment. This potentially contributes to more interaction between negative ions and the human body. 

Does a wood fire sauna stove differ from an electrical stove for negative ion generation when water is tossed on hot sauna rocks? There is a gap in the research in this area. 

Some think negative ions are hocus pocus but as an engineering scholar, I think this is a provocation for further action. 

Resources needed to research further: ion counter, electrical sauna stove, wood sauna stove, controlled sauna environment, psychological and physical assessments, and willing participants. 

Is there a negative ion detector, i.e. a chemical device? — Ion counters, unsure on accuracy and validity of measurements obtained with ion counter devices. 

Additional things I find interesting: 

• mechanical and structural impacts on internal fluid flow and optimization of sauna performance – circulation and heat distribution. 
• humidity and influence on negative ions
• Steam and water generated negative ion concentration

Background research

Article: Air ions and mood outcomes: a review and meta-analysis

Link to study here:

No impact of negative ions on anxiety, mood, relaxation, and sleep was observed in many studies. Though some studies have found sauna usage with the presence of negative ions reduced seasonal affective disorder in many cases (good for northern states/countries that go through long and dark winters).  Negative air ionization was associated with lower depression scores particularly at higher exposure levels – still a preliminary conclusion.

Article: Negative air ions created by water shearing improve erythrocyte deformability and aerobic metabolism 

Link to study here:

• The Lenard effect describes the generation of negative ions by the effect of water shearing.  
• Water-generated negative ions have a longer lifetime than electrically generated negative ions.

Article: Water-generated negative air ions activate NK cell and inhibit carcinogenesis in mice

Link to study here:

• Water generated ions have a long life and were found to significantly enhance cytotoxic activity of natural killer cells, and significantly decreased the incidence of cancer and inhibited tumor growth in mice. 
• Water-generated negative ions are created by the ionization of water through the Lenard effect.
  • As water breaks up into small droplets electrons are arranged on the surface of small water droplets in a dipolar fashion, which combine with the abundance of oxygen molecules in air

Article: Physical effects of negative air ions in a wet sauna

Link to study here:

• Negative ions had the effects of increasing the body temperature, sweat production, and pulse rate to a significant degree as well as enhancing the effects of the sauna bath.

Daniel’s bio: I am a Senior specializing in Mechanical Engineering at Twin Cities Engineering; an ABET-accredited program through Minnesota State University, Mankato. With a B.S. in Psychology, I am an accomplished scholar and have gained many academic accolades to date. I have a passion for gaining knowledge, innovation, and creating solutions. I am captivated by all things engineering and spend my time researching, tinkering, building computers, designing, and 3D printing. I enjoy philosophical discussions, playing board or video games with friends, and rock climbing.