Nausea is simply awful. We all know from personal experience how unpleasant and incapacitating the sensation can be, but thankfully most of us experience it only occasionally — when fighting off a viral infection, or after being hit with food poisoning.
Millions of people, however, suffer from debilitating nausea on a daily basis. Cancer chemotherapy patients, pregnant women, and those with digestive disorders are among the many who are desperate for help. An improved understanding of how nausea happens in our bodies and minds will hopefully lead to more successful prevention and treatment. The sad truth is that nausea is not managed well by standard medical interventions. Drugs prescribed for nausea are far more effective for preventing vomiting than for actually relieving nausea, and the side effects are often intolerable.
As an experimental health psychophysiologist and a professor in the psychology department at Siena College near Albany, N.Y., I research how expectation, perceived control, and psychological stress impact the development of nausea, and an abnormal pattern of stomach activity called gastric dysrhythmia that typically accompanies it. Combined with other scientific research on the role of our gastrointestinal, cardiovascular, endocrine, and nervous systems in how often nausea occurs and how severe it is, my studies may lead to a better understanding of nausea, and better treatments for it than we have now.
Using a special motion sickness simulator that can induce nausea, my team and I have found that being fully informed of how much discomfort to expect, distracting oneself with music, and doing meditative or relaxation exercises can reduce not just our perception of nausea, but the physiological changes that come with reports of symptoms as well.
Under normal circumstances, the stomach contracts slowly and rhythmically at a rate of about three times per minute. We have found, however, that reports of nausea tend to be accompanied by the development of what is referred to as gastric tachyarrhythmia, in which these contractions become more rapid and erratic. The more of this abnormal activity there is, the greater the nausea.
The goal of successful treatment, therefore, may be to stop gastric dysrhythmia from developing, through medication, or behavioral and psychosocial means. Other studies show that nausea tends to be aggravated by activation of the sympathetic nervous system (a hallmark of the stress response), and that nausea is correlated with increased levels of a hormone called vasopressin in the bloodstream.
As revealing as these studies have been, we still don’t completely understand what it takes to consistently help people avoid nausea, or at least reduce the discomfort it causes. Nausea, much like pain, is subjective, so it’s reasonable to suspect that psychosocial and behavioral factors might also play a significant role in how intense our symptoms feel. It’s critical, therefore, that we explore these factors while maintaining an interest in the physiological influences, and to consider the interactive effects of both mind and body on the severity of one’s nausea.
Many of the studies that have been done in the Health Psychophysiology Laboratory at Siena involve inducing nausea with a motion sickness simulator. Participants sit on a stationary stool inside a spinning cylindrical device lined with alternating black and white vertical stripes. This “rotating optokinetic drum” induces the illusion of motion, and physiological signals and symptom data are collected.
As the participants view the motion of the stripes around them, they feel they are spinning in the opposite direction of the drum’s rotation. The participants never actually move at all, and the sensory mismatch between the visual perception of motion and the bodily sensation of stillness is sufficient for many individuals to begin to experience nausea and motion sickness.
This paradigm has allowed for the systematic investigation of the physiological characteristics of nausea, and how different behavioral and pharmacological interventions can prevent it.
In a recent study, my students, colleagues and I found that participants given control over the operation of the device, and those who were given information about the nature of the stimulation they would receive, fared significantly better, both in terms of the intensity of their reports of nausea and the development of gastric tachyarrhythmia.
Participants who were allowed to have a remote control to turn the drum’s rotation on and off didn’t necessarily use it; the mere belief that they could stop the stimulation whenever they wanted — and therefore dictate the outcome of a potentially unpleasant situation — was apparently enough to reduce both the subjective and physiological signs of nausea.
Likewise, participants who were told how long they would be exposed to the rotating drum, and given periodic updates about how much time remained, enjoyed reduced nausea and gastric dysrhythmia. Having both control and predictability was understandably the best-case scenario, reinforcing the idea that knowing when a stressful encounter will begin and end and what it will likely involve, and also having the means to do something about it, is most beneficial.
Other studies I have conducted have focused on social and cognitive processes such as distraction and expectation. Participants who listened to their preferred music while exposed to the rotating drum, for instance, developed significantly less nausea than those who were not distracted. Presumably, engaging in something pleasurable had the desired effect of redirecting the focus of the participants away from the negative experience of nausea and towards the positive experience of enjoying a familiar tune.
One of the studies of the role of expectation produced rather unexpected results. Participants who were led to believe that the placebo pills they were taking might make their experience in the motion sickness simulator especially unpleasant developed significantly less nausea and gastric dysrhythmia than participants who were told the placebo pills would protect them from harm. It was reasoned that participants who were told to brace themselves for something difficult were more prepared for what ultimately developed, while participants who were told their experience would be a walk in the park were alarmed or caught off guard by the initial development of the same symptoms.
Yet another group of studies focused on the role of psychological stress in the experience of nausea and the development of gastric dysrhythmia. In one study, we asked participants to complete a difficult, stress-inducing, cognitive task called “shadowing” while they were exposed to the rotating drum. Shadowing involves listening to a recorded speech, and simultaneously repeating back aloud the words that had been heard just moments earlier. Results of the study showed that shadowing induced physiological signs of stress like elevated heart rate and increased perspiration, and also resulted in the development of more intense nausea and gastric dysrhythmia.
Another study evaluated the benefit of a meditative exercise called progressive muscle relaxation. Some participants were led through a 10-minute activity involving alternately contracting and relaxing large muscle groups while sitting in a comfortable chair and listening to soothing music before being exposed to the rotating drum. Others were not. As expected, participants who first practiced the progressive muscle relaxation developed less nausea and exhibited fewer physiological signs of distress than participants who did not.
What is perhaps most impressive with the results of these studies is that each of the psychosocial manipulations mentioned had a significant impact on both the development of nausea and its underlying physiological mechanisms. In other words, they genuinely affected the development of nausea. For that reason, they deserve considerable attention in the fight against nausea, particularly for patients who have not responded well to the few available biomedical interventions.
I hope these results will have profound implications for the effective, non-drug treatment of nausea related to chemotherapy, gastrointestinal disorders, pregnancy, motion sickness, and post-surgical care.
Specifically, it appears to be important to help people feel like they have at least some control over how their treatment proceeds, and that they know exactly what to expect as they prepare for a round of chemotherapy or other nausea-inducing event. This can help provide a sense of predictability.
These results also suggest that for those likely to suffer from nausea, it is important for them to identify an enjoyable, non-stressful activity that can distract them from whatever is likely to cause the nausea.
Perhaps most importantly, it is inferred from these results that a significant part of preparing for a battle with nausea should be some form of relaxation or stress-reduction, like the progressive muscle relaxation exercise used in my laboratory. This or other forms of mindfulness-based meditation are likely to induce a healthier physiological state for people about to endure nausea, and an enhanced positive state of mind may help people avoid nausea, or at least diminish its intensity.
The results of this research could ultimately inform the development of effective intervention strategies for patients who frequently suffer from nausea, and for everyone else who is fortunate to suffer only occasionally. Let’s hope so.
Max Levine, Ph.D. is associate professor of psychology at Siena College. Dr. Levine received a B.A. from Franklin & Marshall College and an M.S. from The Pennsylvania State University in biological psychology. He also earned his Ph.D. in biological psychology from Penn State and held a post-doctoral fellowship there. He served as assistant professor of internal medicine and psychology at Wake Forest University. Dr. Levine conducts research in gastrointestinal psychophysiology; ingestive behavior; and stress and health.