Soda Baths Decrease Stress, Improve Sleep and Immunity

When I was a teenager, my dad and I took a road trip to one of his favorite places in New Mexico–a hot springs called Ojo Caliente.  At the time, it was a local spot far off the beaten path.  There was a ladies’ and a men’s bathhouse–you would go inside, disrobe for the day, and soak in tubs and pools of natural spring waters; each pool had a different mineral content, and thus a unique healing property. When you were fully soaked, then they would wrap you in hot towels and you would lay there in sweaty heaven until you were a limp rag. Ahhh.  It was the OG, the precursor to today’s fancy spas and elaborate detoxification protocols.  Ojo Caliente is still there today, still beautiful and healing, but with a more upscale vibe and a different clientele.

Soaking in warm water is part of our human health tradition!

Many cultures have a tradition of healing by soaking in hot mineral waters.  The Jewish mikveh, German water cure, Icelandic lagoons, Nordic hot springs followed by cold plunges, Japanese baths and so on.  We fundamentally know from the experience in our body that soaking in hot waters is relaxing, calms the brain, and opens us up to healing.  My question has always been how the natural mineral content in the waters specifically improves health?

Soda baths have extra benefits for Sleep and Stress

A recent study out of Japan looked at the impacts of bathing in bicarbonate rich water on stress, sleep, and immune function. (You can check out the study and my commentary on it in the Natural Medicine Journal here) Many hot springs across the world, including Ojo Caliente, advertise that they have “soda” pools.  Soda, of course, meaning baking soda, which means there is a high bicarbonate content in the water.  This particular study used a standardized bicarbonate tablet to turn a normal bath into a bicarbonate bath–sort of a “bringing the hot springs to your own home”.  I love this, because it means that we could all potentially get the benefit of these healing waters in our own bathtubs. 

There were a few particularly interesting things the researchers found in this study. While all warm water bathing improved measures of sleep and stress, the bicarbonate bath had an amplified effect.  Participants in the bicarbonate arm of the study fell asleep faster, and were able to get out of bed faster in the morning, and felt like they had slept better than participants who took bicarb-free baths.  Also, the bicarbonate bathers, who had categorized themselves generally as stressed, had greater improvement in perceived stressors.

Soda Baths Make us more popular?

One fascinating effect that was reported by the bicarbonate bathers was improvement in their perception of social support.  While it is easy to see how a relaxing bath would ease the mind and decrease production of stress hormones, how could it impact things outside of their control? The authors of the study postulate that this is related to increased blood flow to the brain, improving cognition and easing stress. These researchers performed an earlier study that found that bicarbonate bathing leads to absorption of carbon dioxide, which turns into bicarbonate in the bloodstream. Bicarbonate then acts on the cells in the blood vessels to produce Nitric oxide, which then causes the blood vessels to dilate.  This causes increased blood flow to the brain, which helps people to think more expansively.

Extra Support for the Immune System

A final benefit found in this study was a positive shift in immune function.  Researchers measured immune cells in the blood of participants before and after the study.  They found that cells that increase inflammation in the body decreased, anti-inflammatory mediators increased (aka–decreasing inflammation) and anti-tumor cells increased as well. The authors propose that bicarbonate bathing decreases stress, which positively impacts immune function by shifting the production of cells toward less inflammation and an improved ability to fight cancer cells. 

In contemporary Western society, we lack regular rituals of rest that help to engage the parasympathetic nervous system and promote healing and rejuvenation of the body. Many of us have high levels of stress, are under-rested, and have trouble getting good quality sleep. Over the long term, overproduction of stress hormones increases inflammation in the body and can contribute to chronic issues such as cardiovascular disease, blood sugar dysregulation, and cancer. This study shows us what we innately know already:  regular warm-water bathing is an easy, low-cost way to create such a ritual. Further, this study shows us that adding bicarbonate to our baths could amplify this effect. 

So, how can we get the relaxing “Ahh” of the spa at home? Well, adding any type of regular bathing (hot tub, bathtub, steam room at the gym etc) will certainly help with stress and sleep.  For the extra benefit of bicarbonate found in this study? A quick Web search shows the only products similar to that used in the study are produced in Japan (where the study was performed) but can be found on eBay and Amazon. Because of the added citric acid and sodium carbonate, I do not know if simply adding baking soda to the bath would have the same effect. But adding some baking soda in the bathtub or ordering some bicarbonate tablets would certainly be worth a try!