So shifting gears a little bit and I want to talk a little bit about Stress and Health. So we talked a lot about positive affect and health, but I also want to talk about stress and health and what we know about the stress response and what it does to the body. So of course, going to the media, stressful events may raise risk of falls. So we're not only talking about stressful and chronic stress, but also stressful events, actually having what might seem to be unrelated or potentially paradoxical influences on physical outcomes. This speaks to the point of not only being in chronic stress or strain, but that individual stressful events as they accumulate are also important when looking at this whole relationship. So these are items from the perceived stress scale, and this is more of a construct where you're looking at the continuity and chronicity of stress. So questions like, have you often felt that you were on top of things? Are you often able to control irritations? So you can see here that these questions are like, are you getting stressed out on a pretty continual basis? Is this like almost the dispositional set and things like anger, irritation, and so on, which is different from these stressful events which are usually evaluated in terms of tick marks of like, have you experienced this in the past four weeks or in the past 12 months? So you can look at these stressful event scales and this is the one that ties back to that article about older men and falling. That series of studies specifically had to do with sympathy accumulation of stressful events. You can see here that there are some positive events. It doesn't have to be sad things like death of a loved one or a relationship terminating. It can be good things like getting married or moving, or taking a new job. So the accumulation of these things then also matters. Anything that stresses the system or causes a jolt to homeostasis is actually defined as stress. So stress in these ways, either chronic or accumulation of stressful events does also have outcomes, or have associations with health outcomes. Stress contributes to disease onset similar to what we talked about in the previous video segment, that there are different vulnerabilities. So the more one is in a stressed state predicts the development of vulnerability to disease, also worsen symptoms and makes it a much more difficult time to recovery and hastens mortality. Here's another set of experiments. So we talked before about positive affect categorizations that influenced the development of disease. Now this actually is a similarly prospective study in which people were evaluated for the number of stressful events and then we're exposed to a virus or a placebo. They were young and middle aged adults many of them, no act of illness and not being currently on any medication regimen and they were evaluated in the first couple of days, blood draws, took their basic blood pressure, heart rate and so on measures, and also underwent some clinical interviews. Then they were exposed to either a virus or a placebo. So baseline, figuring out where they are stress wise then exposing. Then evaluated symptoms over the course of the subsequent seven days and found the following; they had both stressful life events as well as the perceived stress scale, which is this chronic undercurrent of how stressed out you are. This is like boiling downloads contracts. So this is how stressed out you are and then stressful life events is, this is how many things have happened to you, how many stressful things have gone on. Then they also influence negative effect in the form of like depressed mood and so on. Then measured signs and symptoms and found the following; first of all, there was very little difference from the observed to the adjusted. As you can see after they adjusted for age and education, the demographic factors for which you typically adjust. What we see here is that those in the highest psychological stress categories going up to a 12 point scale, had a much greater likelihood of developing a cold. Whereas those who reported lower levels of stress with respect to the dispositional chronic strain were much less likely to develop a cold. Now shifting to the actual life stressors. Same researchers here, but a different study and this one they actually looked at the chronicity of life stressors of how long these things persisted and you can see here that with the greater persistence, the relative risk of becoming sick with a cold was increased substantially. So the longer the stress goes on, the more vulnerable. So we've learned from this set of studies is that stress both in the acute way, measured by constancy of changes but also in the more chronic persistent dispositional way as associated with becoming ill in a very dose-response manner. The more stress, the greater the vulnerability. This is consistent across a variety of viruses, and depending on the type of exposure, the effect might be even greater up to and approaching like a sixfold odds ratio, and the mechanism when we can speak near an EMD. A little bit greater, but I always think that this is important stuff for everybody and EMD to also know and appreciate that we're not simply talking about a single virus but the complex interplay with which that manifests. Are these are the things that you learn in EMD classes? Not quite. No? Well, social behavioral for complicated in the picture a little bit more. So I also want to point out that actually this is not even limited to viral exposure and EMD [inaudible] factors that this is also kind of trickles back into the behavioral domain as well and this series of studies and again, this is a popular media headline, but I'm bringing it down to what the actual research was, is that in this study women reported the stress that they were experiencing and then were randomized to two different diet groups and found that the stress interacted with the diet in terms of how their inflammation response emerged. So typically, inflammation is in response to one type of diet, but the basically the healthier diet effects were attenuated or dissolved when stress was present, so that stress could even overpower the healthfulness of the meal.
