Stress is bad.

But trying to figure out why it is bad is pretty difficult. Part of the problem is, some people experience stress differently than others. Some people seem to slide right through life’s issues and come out the other side as if nothing happened. Other people, it seems, can have a major crisis if they so much as get a hangnail that week. To further complicate things, the difference in how people experience stress seems to also play a role in disease and, as they say, stress leads to disease.

The problem is, that’s not entirely true. You see, the medical community has been playing badminton with this issue for quite some time. They have found a lot of correlational studies, like the link between cardiovascular disease and stress and the link between obesity and depression. There’s also a correlation between diabetes and obesity and one between diabetes and depression. These are correlations, but correlation, as they say, is not causation. BUT that doesn’t mean that correlation is not important. Correlation is very important. It just isn’t a cause.

This means that stress probably doesn’t cause disease, but it is possibly related to the progression of some diseases.

What we know:

Stress can decrease some immune system functions while increasing others. Because of how medical science is reported in the media, people’s understanding of the immune system is limited. Thus, when it was announced that some researchers had seen changes in the immune systems of people under stress, the media interpreted it as a kind of universal reaction.

Instead, stress-response by the body is pretty complicated. What we’ve found is that stress does change our immune system, but that, alone, doesn’t lead to disease. In fact, some types of immune response during stress are improved while other types of immune response may leave part of your body vulnerable and what happens during your stress-response depends on the type of stressor and the duration of stress. Thus, stresses like exercise are an overall benefit to the immune system. That doesn’t necessarily mean you won’t be a little more sickly during an exam.

But, the immune system doesn’t protect against all types of disease. Many diseases are not germ-based and some of those diseases are also correlated with stress. When you look at studies on heart disease and stress, you’ll find an endless list and much of the information is confusing. Because medical science is still trying to work out the details, what you find may seem inconsistent. Again, what we do learn is context-specific. Marital stress seems to make heart disease more dangerous for women.

While medical science is still trying to tease out how stress relates to heart disease, in most respects, there’s significant evidence that if risk is there, stress can trigger heart attacks. The sad side of this information is that it comes from natural ways to find a direct correlation: tragedy. Of course, triggering the worst consequence of a disease is not, itself, causing the disease. Individual heart attacks are caused by a blockage in an artery that prevents blood from flowing to the heart. We already know that stress does lead to an increase in blood pressure and an increased heart rate. Thus, with the pre-existing condition of plaque-filled arteries, loose plaque or blood clots, we can easily see how a little stress can trigger a heart attack, while the cause of the heart attack was a blood clot and clogged arteries.

Cancer is also correlated with stress, but we don’t know exactly why or how. In fact, we know so little about stress’ correlation to cancer, I hesitate to even expound, because I don’t want to say something without more confidence in the data.

But, even with cancer, there seems to be confusion by the public that cancer is caused by stress, but that’s not what the evidence seems to say. Instead (see the above link) most studies on cancer and stress show cancer growth increasing when the individual is under stress. This doesn’t mean cancer starts with stress, it just means cancer is likely more harmful in those who are stressed, already.

But, even this article isn’t so simple as it seems. Remember where I mentioned that exercise seems to benefit the immune system (with some sort of implication that exercise decreases stress)? Well, as it turns out, even that is a conditional thing. While there are health benefits to exercise, including it possibly reducing your stress levels overall, if you’re stressed before your exercise, those effects may not be quite as beneficial, since your risk of heart attack seems to increase.

So, going for a run on a normal day might not be a big deal, but running from this:

That could be the added stress needed before a run to end your life early from a heart attack. If it happens daily and you don’t end up meeting the bear for lunch, I mean.

Of course, this completely ignores our problem over most correlation health studies. Does the stress come before the illness or does the illness come before the stress? Most of the time, we can see links between things, but there are too many variables to pin one thing down as being a cause. Sure, stress may lead to a person doing this:

But that is not an immediate risk. We also know that obesity correlates with depression in such a way that the more obese a person is, the more likely they are to suffer from depression and the more weight a person loses, the less depressed they seem to become. So, where stress and depression are linked, we can’t really say that stress is the causation of various risks associated with obesity, including heart disease, diabetes or cancer.

So, you may wonder, why is this important? It is important because people make decisions about their health based on information they get from the general media. The media seems to advocate this idea that stress causes disease and that idea feeds into various types of bad science.

Some examples:

Herbs to reduce stress, making odd claims about toxins, stress attacking you and even an apparent misunderstanding of evolution.

Accupuncture to treat stress, with dangerous symptoms that might require immediate medical care.

Even a recognizable network like TLC has information worth questioning when they make claims about stress-caused illness and then suggest aroma therapy.

I want to be clear about something. It isn’t that we shouldn’t try to reduce our stress levels. Seeing a correlation between stress and health should be something that makes us pro-active and even somewhat concerned about our stress levels. At the same time, the outright claims made about stress causing certain health problems (when they confuse correlation with causation) can lead to people ignoring the very real causes that we are aware of. It can also lead to people making poor decisions about their health. The benefits of abstaining from a greasy burger is not the same set of benefits that someone might gain from an hour of meditation or dropping out of an especially challenging project or class. When it comes to changing something like eating habits or exercise, we at least have more solid data on how that benefits us than we do over how to deal with stress.

Of course, since stress really can be a trigger for life-threatening conditions, it is reasonable to reduce stress if you are at risk for a heart attack. At the same time, be aware of what is actually causing that, so that you can change other parts of your lifestyle as well. Stress doesn’t appear to be the cause of disease. Rather, stress seems to trigger disease-related problems and can increase your predisposition for certain health problems and diseases because of how it affects your immune system, cardiovascular system and even your cellular chemistry. Since enabling a disease is not causing the disease, take care of yourself in ways that are practical, first.

After that: