Does Salt Water Actually Heal?

Being from a place surrounded by the ocean, whether it's in cultural stories or printed on T-shirts and hats, you hear and see the phrase “salt water heals” very often. And personally, I think it's true. After a long day or if I feel under the weather, a dip in the ocean makes me feel much better, which makes me wonder if there is a measurable physiological basis for it. 

After doing further research on the topic, it seems this is something that scientists have been trying to connect for a while but data is limited in the mechanistic and epidemiological principals. One study I found particularly interesting done by Hooyberg et al (2023) compared beaches to green and urban environments looking at their influence on physiological stress. Researchers showed 164 participants two 16 minute exposures using virtual reality while monitoring their heart rate, heart rate variability, skin conductance, blood pressure, breathing rate, and muscle tone. The study showed that beaches caused lower breathing rates than urban environments and lower sympathetic nervous system activity than green environments. Participants also stated that, under moderate stress, they felt the beach scene decreased negative mood and perceived stress where the green environments did not. 

An additional study that I found complimentary to the last one was done with a random crossover design. 59 healthy adult office workers were randomly assigned to either a blue space, urban space, or control site on 4 days each week for 3 weeks. For 20 minutes a day participants walked along their assigned space. After the walk researchers measured self-reported well-being (also assessed duration of effects at least 4hrs after exposure) and mood, blood pressure, and heart rate variability. They found that participants' well being and mood responses were significantly improved after walking in the blue space compared to the urban space and control site. However there was not a statistically significant difference in cardiovascular response in the blue vs. urban space (Vert et al., 2020). 

The most interesting part about both of these studies is that the feeling of relief is consistent with the blue space/ ocean. The fact that the biomarkers were pretty inconsistent shows that the oceans effect might set off smaller shifts in mood rather than one big stress switch. I would love to see future studies use a more hormonal approach with markers such as cortisol and follow people for longer periods of time. 

References:

Everaert, G., Aerts, R., Bourgois, J. G., Buysse, A., Covaci, A., De Rijcke, M., Diopere, E., Hooyberg, A., Lachat, C., Lahousse, L., Mees, J., Michels, N., Plusquin, M., Raes, F., Rappé, K., Roose, H., Severin, M., Van Campenhout, K., Vanhaecke, L., … Asselman, J. (2025). Ocean for Health: A Transdisciplinary Framework to Accelerate Research on Ocean–Human Health Connections. Environmental Science & Technology, 59(27), 13585–13593. https://doi.org/10.1021/acs.est.5c05463

Hooyberg, A., Michels, N., Roose, H., Everaert, G., Mokas, I., Malina, R., Vanderhasselt, M.-A., & De Henauw, S. (2023). The psychophysiological reactivity to beaches vs. to green and urban environments: insights from a virtual reality experiment. Journal of Environmental Psychology, 91, 102103. https://doi.org/10.1016/j.jenvp.2023.102103

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Vert, C., Gascon, M., Ranzani, O., Márquez, S., Triguero-Mas, M., Carrasco-Turigas, G., Arjona, L., Koch, S., Llopis, M., Donaire-Gonzalez, D., Elliott, L. R., & Nieuwenhuijsen, M. (2020). Physical and mental health effects of repeated short walks in a blue space environment: A randomised crossover study. Environmental Research, 188, 109812. https://doi.org/10.1016/j.envres.2020.109812

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