With a short stab at describing the involved processes
A quick search on your favorite search engine will quickly yield many results on what hiccups are, what causes them, and potential solutions, yet very few of them seem to work consistently. Sure, drinking water works sometimes, having someone pat you on the back may work some other times, and perhaps even hanging upside may work for you, but it seems that the solutions don’t always work and often take different periods of time for them to work — if they work at all.
It would be nice if there was a potential solution that worked consistently, but search results vary widely in their suggestions, ranging from eating something sweet, eating something sour, having honey, having someone frighten you…..
One suggestion I read a long time ago that seemed to work consistently involved holding your breath. What’s the scientific rationale for this? It seems there haven’t been any studies on this so there aren’t case studies to look to, but since hiccups are involuntary contractions of your diaphragm muscle — and the diaphragm muscle is the primary muscle involved in the respiration process — holding your breath may temporarily reduce the muscle activation of your diaphragm, thus potentially indirectly reducing the involuntary contraction of your diaphragm and addressing the source of your annoying hiccups. There have also been claims that holding your breath increases carbon dioxide buildup, and that it is the buildup of carbon dioxide that helps with hiccups, but I’ll focus on the respiration process here since I think the physiological process involved provides a better approach to understanding hiccups than the carbon dioxide explanation.
A quick explanation of the respiration process will be useful in understanding the reasoning, so here’s a short and non-exhaustive overview of what goes on when you inhale and exhale:
The diaphragm pulls air into your lungs by contracting and moving down to increase space in your chest cavity, effectively creating a vacuum when you inhale, and helps expel air by relaxing and moving up into the chest cavity . The diaphragm isn’t the only muscle involved in breathing, however, with the intercostal muscles also playing a role in aiding with the expansion and shrinking of the chest cavity , and the muscles in your neck/collarbone region and your abdominal muscles also playing a (much smaller) role in the respiratory process.
This is by no means a comprehensive explanation, but the aim is to provide you with enough info to give you a basic understanding of what is happening.
By holding your breath after inhaling and exhaling, you reduce the frequency of muscle contraction/relaxation of your diaphragm, and perhaps temporarily reducing the number of contraction/relaxation cycles that your diaphragm has to go through helps alleviate your hiccups.
With this in mind, we can go back and think of the different solutions offered and why they sometimes work and sometimes fail miserably. By drinking water, sucking on a lemon, or eating something (sweet, sour, bitter, whatever), you temporarily interrupt the respiration process to swallow your drink/juice/food, and perhaps it is the interruption of the respiration process that sometimes helps stop your hiccups, and not the thing that you are eating or drinking itself actually interacting with your hiccups in some way.
Perhaps this is why having someone scare you or hanging upside down works sometimes — both of these things modify your breathing in some way, with your breaths becoming short and shallow when you’re frightened and slightly strained when you’re upside down (unless you breathe normally upside down, but most people aren’t bats and tend not to breathe the same when they’re upside down).
Understanding this process may also help explain why these solutions sometimes don’t work: if you eat or drink something, have someone scare you, or hang upside down but don’t change your respiration pattern very much prior to doing said task, then it doesn’t affect your respiration and thus your diaphragm in a significant enough way to affect your hiccups.
Since there’s no comprehensive study that offers a solution for hiccups— or even a consensus of what is happening — this was my attempt to explain a process that is a common occurrence. Try this out the next time you get hiccups, and see if it works! This may not be entirely correct, however, so feel free to leave a comment with your take on the issue below.