Few of the so-called rules for healthy living — such as exercise every day and get annual checkups — are supported by scientific evidence. Yet millions of Americans feel guilty if they don’t follow these and other specific dos and don’ts.
The fact is that people at either extreme in their health habits (those who totally neglect their health and those who behave obsessively about it) tend to be less healthy than those who occupy the middle ground.
What’s hype and what’s healthy…
Healthy people who see a doctor for an annual checkup every year are, on average, no more likely to avoid disease than those who never get annual checkups. The bottom line is that annual physicals do not change health outcomes. I advise patients with existing health problems to see a doctor regularly to review medications, track changes in symptoms and so on. (Check with your doctor about how often you need to see him/her.) People without health problems can safely avoid the inconvenience and expense of yearly visits.
That said, some regular screenings are recommended even if you are otherwise healthy. Blood pressure, for example, should be checked every two to three years and cholesterol, every five years.
A good night’s sleep usually is defined as eight hours of continuous rest. The study most often cited in support of this was conducted in 1993 and focused on 16 volunteers who spent 14 consecutive hours in bed in a darkened room. At first, the volunteers slept an average of more than 12 hours a day. After a few weeks, most reduced their sleep time to seven-and-a-half to nine hours. The researchers concluded that the volunteers slept a lot at first because they were typical sleep-deprived Americans who needed to catch up and that the seven-and-a-half-to-nine-hour range was the optimal amount of sleep.
But the study really only indicates how much people will sleep when they have nothing else to do. If you get less sleep, is your health going to suffer?
Most studies that connect sleep loss with illness have focused on people who get only four hours of sleep or less for several consecutive nights. Other studies show that people who get six or seven hours of sleep each night live longer than those who get eight hours or more.
What’s right for you? Listen to your body — and don’t worry about getting the same amount each night. It’s fine to get more sleep on some nights and less on others.
Millions of Americans are obsessive about exercise. They feel guilty if they miss their workouts or give up exercise altogether when they find that they can’t live up to an all-or-nothing ideal.
People who are fit clearly are healthier than those who aren’t, but this isn’t the same as saying that everyone needs to exercise for 30 to 60 minutes most days of the week.
Proponents talk about studies that show that people who exercise have lower rates of heart disease, cancer and other diseases. What they neglect to mention is that most of these studies are observational — they track behavior over time, usually through the use of questionnaires.
Observational studies are good for developing hypotheses, but they don’t distinguish cause and effect. Maybe people are healthier because they exercise… or maybe people exercise because they’re healthier to begin with. The evidence is not clear.
This is particularly true for younger adults, who typically incorporate a lot of natural movement into their daily lives, from chasing after young children to working in the yard and cleaning the house. No one thinks of these activities as exercise, but people who do them usually are pretty fit.
After age 50, when people are less active in general, regular exercise makes more sense. People who exercise most days of the week do have a lower risk for heart disease, and they’re less likely to get diabetes. Exercise also can help alleviate insomnia and depression.
Are you worried about your weight? Most American adults are. Yet there’s little evidence that people who are moderately overweight are more unhealthy than those with slim physiques.
Even if you’re heavier than you would like to be, the odds that you can lose significant amounts of weight are against you. New research indicates that every individual is born with a genetically programmed weight range, give or take 10 to 20 pounds.
You might hover at the lower end of that range when you’re watching your diet. You might drift toward the upper end around the holidays or when you’re on vacation. But most people stay roughly within their natural range, regardless of how much or how little they eat or whether or not they exercise.
Of course, if people eat much too much for way too long, even those who are naturally slender can blow the ceiling off their weight range and become obese, which can lead to serious health problems, including diabetes, heart disease and cancer.
Whether you’re naturally slender or rotund, your goal should be to stay roughly in the middle of your natural range. The danger is at the extremes. People who are too heavy or too thin tend to die sooner than those in the middle.
More is not better. Most US health agencies advise women to get their first mammogram at age 40 and then have them annually.
Some doctors recommend a “baseline” mammogram at age 35 just in case a surgeon needs a reference point at some time in the future. This is reasonable advice for some women, but not for all women. Speaking as a surgeon, I can attest that doctors almost never consult a baseline mammogram.
It’s true that annual mammograms in women over age 50 can reduce the death rate from breast cancer by 30%. Young women are different. Their overall risk from breast cancer is low, and their denser breast tissue makes mammograms less effective.
Also, mammograms have their own dangers. Younger women face higher risks from radiation than older women. And those who get mammograms every year in their 40s face a 20% to 56% risk of getting a false positive, a reading that suggests a problem when in fact no problem is present. This can lead to unnecessary biopsies or surgery.
For most women in their 40s who do not have a family history of breast cancer, a mammogram every two or three years is fine. If you do have a family history of breast cancer, however, you should have mammograms annually after the age of 40.
