Can a positive mindset protect us from the sniffles?

The threat seems to be everywhere. On the tube, on the bus, as I the queue for coffee, I find that I am surrounded by coughs and sneezes, spreading diseases. I eat healthily, exercise and try to get 8 hours of sleep to fend off the dreaded lurgy. It is only recently, however, that I started wondering whether our mental life might also play a part in our body’s defences. And the more I dug into the available literature, the more convinced I have become that it is critical. Our attitudes, I have discovered, can subtly shape our immune system’s activity, which directly influences how likely we are to develop symptoms. If we want to fend off infection, we would do well to look after our minds as well as our bodies. Advertisement One of the first studies to explore this possibility arrived in the early 2000s, when Sheldon Cohen at Carnegie Mellon University in Pittsburgh, Pennsylvania, and his colleagues recruited 334 plucky volunteers who were willing to be infected with the common cold. In the month before the trial, they took regular questionnaires about their feelings throughout the day, noting emotions both positive (cheerful, at ease, energetic) and negative (sad, on edge, hostile). On infection day, the scientists gave each participant a nasal drop containing one of two rhinoviruses known to cause sniffles, then held them in quarantine for five more days to observe whether any symptoms developed – quantified through objective measures. The team estimated the participants’ mucus production, for example, by collecting and weighing the snotty tissues they had used. Cohen’s results were unequivocal. People with a sunnier emotional style were about a third less likely to develop symptoms than those who were less positive. Quite amazingly, the influence of the positive feelings was independent of the negative feelings – meaning that people who managed to feel both cheerful and anxious, for instance, were still less likely to develop symptoms than those who were neither cheerful nor anxious. This may sound counterintuitive, but it is perfectly possible to feel multiple emotions at the same time, and Cohen’s results seemed to suggest that positive feelings play the greatest role in our health. I might have been sceptical if this were the only evidence, but multiple other studies have since confirmed and extended these findings. Cohen and his colleagues have shown that a so-called positive emotional style (PES) could also protect participants from influenza, for example – even after they controlled for a host of factors including age, sex, education, race and body mass. While the exact mechanisms are unclear, it almost certainly comes down to stress, which is known to throw our defences into disarray. Someone under a lot of pressure may struggle to summon the resources to identify the virus when it first takes hold, leading to a suppressed immune response. Alternatively, the immune system may leap into action too quickly and too eagerly, bombarding the body with the inflammation that lies behind many of our symptoms. In the case of the common cold, it seems that the second potential mechanism is the most relevant. Someone with a more positive frame of mind may find it easier to cope with life’s stresses, meaning that the body becomes less inflamed when they face a pathogen. Along these lines, Cohen has found that people’s symptoms, such as a runny nose, are directly correlated with their levels of IL-6, a pro-inflammatory signalling protein called a cytokine, after infection. This was much lower among those with a PES. A group of researchers led by Sara Puig Pérez at Valencian National University, Spain, meanwhile, found that optimists have lower levels of another pro-inflammatory cytokine, TNFα, which has been linked to the fatigue and lethargy that often accompanies our sniffles, and this seemed to be reflected in fewer overall symptoms. It seems that the optimist’s body is simply better able to fine tune its response to the threat at hand. As fascinating as this is, I’m mostly interested in the ways that I might use this information to protect myself, so I was delighted to find a trial of an eight-week mindfulness course by Bruce Barrett at the University of Wisconsin-Madison and his colleagues. Like Cohen, Barrett looked for objective evidence of infection, with blood tests, cheek swabs and nasal washes, rather than relying solely on reported symptoms. The mindfulness course had previously been shown to cultivate a more positive mindset – and this had the desired effect on the participants’ health. The participants were generally less likely to develop a respiratory illness after practicing mindfulness. And for those who did develop signs of an infection, the symptoms were less severe. The benefits were comparable to those of exercise, which is also known to increase the efficiency of the immune system. The meditators were also less likely to take time off work due to illness than the control group, who had been put on a waiting list for the course. Mindfulness may not be your thing. As I’ve written previously, I’ve personally struggled with it in the past, although I’m now finding new ways to incorporate it into my life. Given the very general link to good feelings, I’m sure that plenty of other kinds of self-care would bring similar protection. Social connection also seems to boost the immune response, so you might try to reach out to the people who matter most to you, for instance. With the nights drawing in over the northern hemisphere, it is very easy to succumb to the winter blues, so now could be the perfect time to focus on the things that bring you comfort. A sneeze-free sniffle season may just be one of many benefits.