Have you heard the one about marital status and blood pressure? The media has been abuzz about a study on that topic released a few days ago. The research has been featured on Good Morning America, CNN, MSNBC, in an Associated Press report, and many other places.
HERE ARE THE CLAIMS MADE IN THE MEDIA
I typed a few key words into Google to get a sense of the headlines. Here are a few:
1. "Happily married have lower blood pressure than singles."
2. "Marriage may lower blood pressure."
3. "Walk down the aisle for lower blood pressure, but be happy!"
4. "A happy marriage leads to low blood pressure."
5. "Happily marrieds have lower blood pressure than social singles."
Exhibit #6 comes from a pro-marriage listserv. The moderator introduced the study by noting, "This research is all the more reason to help couples learn how to get married..."
For years, I have been examining claims about the links between getting married and getting healthy. (See Chapter 2 of my book, Singled Out.) My approach is apparently different than that of many reporters: I actually go to the original journal article and read what the study really did show. Time and again, the results that make it into the media are a biased version of the actual results of the research, and in just about every instance, they are biased toward making married people look better and single people look worse.
I'll explain how that has happened with this particular study. Sometimes, though, you need look no further than the headline to realize that something is amiss. Take the very first headline, for example: "Happily married have lower blood pressure than singles." The claim is that if you compare only those married people who are happily married, to all singles (regardless of their happiness or anything else), the married people seem healthier.
HERE ARE THE ACTUAL RESULTS
Here's what I learned about the study from reading the original journal article:
Adults from the Provo, Utah community (mostly white) agreed to wear a blood pressure monitor for 24 hours. The married group was comprised of 204 heterosexuals. The 99 singles included 12 who were divorced and 1 who was widowed; the others had always been single.
From headlines such as "Marriage may lower blood pressure," you might guess that when blood pressure was averaged across the 24 hours of the study, the married people would have lower blood pressure than the singles. You would, however, be wrong. There were NO SIGNIFICANT DIFFERENCES in blood pressure between the married people and the single people.
Next, the authors looked at people's blood pressure only while they were awake. Maybe those waking hours, when married participants may have actually be interacting with their spouses, are the times when they look healthier than single people. Wrong again. There were NO SIGNIFICANT DIFFERENCES in blood pressure between the married people and the single people during waking hours.
What's left is blood pressure while sleeping. The authors looked at how much each person's blood pressure decreased while sleeping compared to when the person was awake. The married people had a greater reduction in blood pressure (not necessarily the same as a lower level of blood pressure), by about 3 points, than single people.
That is the key finding that you have been hearing all about: Married people look better than single people only if you compare reductions in blood pressure when the participants are unconscious.
I'm not saying that "nocturnal dips" are unimportant. But really, when you read those headlines, is that what you thought you were learning?
But suppose, hypothetically, that the results had been much stronger. Imagine that the married people had much lower blood pressure than the single people all day and all night. Would it then be okay to say that if you want to have lower blood pressure, you should get married?
Not on the basis of this study. Anyone who has taken a course in psychology or research methodology probably knows why. If married people differ from single people in blood pressure (or anything else), you cannot know, on the basis of this sort of study, whether they differ BECAUSE they are married. Maybe the people who got married already had lower blood pressure even before they married, and getting married made no difference.
Methodologically, there is a great way to figure out whether getting married helps your blood pressure. Unfortunately, it is unethical. You would have to assign people at random to get married or stay single.
The next best thing is to follow people over time. Richard Lucas and his colleagues have done this in a study of happiness that has been ongoing for at least 18 years. They found that people who got married and stayed married throughout the course of the study experienced a small increase in happiness around the time of the wedding. Then they went back to being as happy or as unhappy as they were when they were single. The people who married and eventually divorced did not even get the benefit of a honeymoon effect; they were already becoming less happy, not more so, as their wedding day approached.
There is no comparable study of changes in blood pressure as people transition from being single to being married (or from being married to being divorced or widowed).
WHAT'S WITH THE "HAPPILY MARRIED"?
I've already made fun of the headline claiming that happily married people have lower blood pressure than single people (whether happy or unhappy). The happy qualification covers another finding that some of the reports did mention: Unhappily married people had worse blood pressure readings across the 24-hrs than did the single people. They also had higher blood pressure during the day. Their "nocturnal dips" were not any different.
Hence, some main headings (e.g., "Good marriage equals good blood pressure") were qualified by a subheading: "Bad marriage worse than being single."
Fair is fair. The blood pressure of unhappy married people should be compared to the blood pressure of unhappy single people.
WHAT ABOUT THOSE "SOCIAL SINGLES"?
Headline #5, "Happily marrieds have lower blood pressure than social singles," introduces another factor - whether singles are "social" or not. The title of the published article poses the question, "Is there something unique about marriage?" The press release from Brigham Young University stated that "Having supportive friends did not translate into improved blood pressure for singles or unhappily marrieds." What that summary suggests is that even if you are single and you have supportive friends, you are still doomed to your non-dippy blood pressure.
Now once again, let me tell you what I read in the actual journal article. The measure of "supportive friends" was a 40-item scale. It consists of 10 items measuring your access to tangible, material help (sample item: "If for some reason I were put in jail, there is someone I could call to bail me out"); 10 items measuring whether you have people with whom you can discuss your problems (sample item: "There is really no one I can trust to give me good financial advice"); 10 items measuring whether you have people you can do things with (sample item: "Most people I know don't enjoy the same things I do"); and 10 items measuring your self-esteem (sample item: "I am able to do things as well as most other people").
Single people who had more access to support (as measured by this scale), compared to married people who had more access to support (again, as measured by this scale), had no better blood pressure readings than those who had less access to support. That's the basis for the conclusion that "there [is] something unique about marriage."
Here is the question that the study did NOT address: If you are single, and you have a close friend or a sibling or anyone else who is important to you (or if you have the number of close relationships and the degree of closeness that you desire), then how does your blood pressure compare to a married person's?
If you are single, I don't think you should decide to get married in order to lower your blood pressure. Just relax and get a good night's sleep.
Unfortunately, that probably won't work for me. I'm single, and media reports like these make my blood boil.