That is a very good question, and I am going to try answer your question by not answering your question (because you didn’t actually ask a quesion
).
Human nature is such that we often look to a proximal event to explain something that has happened. For example, if you emit a loud burp, it must be the pint of beer you just consumed. We think that events that are close together in time are causally linked. However, this is rarely the case and life is not so black and white. We have no idea if the symptoms your student experienced were caused by the yoga practice she did, but clearly the practice was proximal in time to her discomfort. So, we tend to link these events and think that there was a causal relationship between them. You are mystified by what that might have been and how to avoid it in the future. Natural, but not necessarily helpful.
Firstly, I would have asked her if she has experienced a dry mouth sensation after yoga practice before? If not, I would not worry about it. One time events that do not re-occur are not worrisome, as most doctors know. If it has happened before, then a closer investigation is warranted.
I would secondly ask about what else is going on in her life. We have two choices to make when determining causes: a biological mechanical approach or a holistic, gardening approach. In the bio-mechanical approach, we have an event which we try to find a mechanical cause for. For example, if every time you stop your car you hear a loud squeal from the tires, there is a great likelihood that your break pads are worn and need replacing. However, suppose your roses in your garden were not doing well. You would have to look at the state of the whole garden to see which remedy is best. Too much shade from the overgrown hedge? Too many aphids since you took out the broccoli? Not enough fertilizer or water? In your student’s situation, other events and situations in her life may play a far more important role than an hour of yoga.
How are her relationships, her job, any changes in diet, exercise levels, stress, has she moved recently, are financial worries, any other medical issues recently, any significant life changes or habit changes? Has she had sleep challenges in the past? How is her mental health? Had she been doing other exercises before coming to your yoga class that may have dehydrated her? Was she suffering any allergies that may have caused her to breathe through her mouth? Was she recovering from something, like a cold?
As you can see, the idea that the yoga practice was the sole cause of her dry mouth and sleep issues is looking at the proximal event and thinking it had a causal impact on her. Maybe it did, but I suspect there is something else going on. Your flow does not strike me as one that would create any of these issues. If it did, I am sure many of your other students would be complaining about the same problem, and I assume they have not.
Now, this is not to say that this one particular yoga practice had no causal relationship. It may have provided a tipping point for her. She may have been on the precipice, the edge of something and this was the last straw that nudged her over. Unlikely, but possible. The key remains, what were the real causal agents in her garden of life that set up the conditions for these symptoms? To answer that, a much closer investigation into what is going on in her life is warranted.
I do not know your student and have no idea what may be causing her sleep disruptions. There are many possible causes, but I doubt that one yoga class, especially a yin yoga class, would be the primary or even tertiary cause. If she is concerned that her sleep issues are continuing, I would recommend she see her doctor and start to evaluate all the possibilities.
I hope this is helpful.
Cheers
Bernie
