In the United States, and around the world, women live longer than men. The average American woman has a life expectancy of 80.4 years; men lag 5.2 years behind. At every age, from conception to seniority, males have a higher death rate than females. Men die younger than women, and they are also more burdened by disease during life. They have more chronic illnesses than women, and they fall ill at an earlier age. Why? It’s the $64,000 question. But there is no single answer. Instead, the gap depends on a complex mix of biological, social and behavioral factors. Possible contributors include: biological factors (men have one X chromosome and one Y chromosome, women two Xs; men have much more testosterone, women much more estrogen; women have higher HDL or “good” cholesterol levels, men more abdominal fat); social factors like work stress and social networks and support systems (men lag behind women); and behavioral factors (men tend to exhibit more risky behavior, aggression and violence, and unhealthy habits like smoking and alcohol abuse, yet they are less likely to see doctors).

Why do men make poor patients? Busy work schedules and competing responsibilities and interests may play a role, but the macho mentality appears to be the chief culprit. When it comes to health, many men put their heads in the sand and deny symptoms for as long as possible. And when they can no longer pretend there is no problem, many grit their teeth and “tough it out” instead of getting prompt medical care. Call it the John Wayne Syndrome or the Ostrich Mentality—by any name, it’s an important contributor to the health gap. Women think about health more than men, and they are more diligent about checkups and preventive care. But men can take simple steps to protect themselves from the heart disease and lung cancer that felled the quintessential American he-man.

Prevention First

Prevention is key to helping men become healthier and live longer. Here are 10 simple steps men can take:

  1. Avoid tobacco and illicit drugs. 2. Exercise regularly. 3. Eat well. 4. Stay lean. 5. Limit alcoholic drinks to one or two a day (if any). 6. Avoid excess stress. 7. Wear a seat belt and behave prudently to avoid accidents. 8. Minimize exposure to ultraviolet rays, radiation, chemical pollutants or other environmental hazards. 9. Use protection against sexually transmitted diseases. 10. Listen to your body, report any problems to your doctor, and get preventive medical care.

If you take good care of yourself, you’ll dramatically reduce your need for medical care. Still, all of us need some preventive maintenance. Here is a rundown of preventive services and major personal goals for each stage of life. Note that they apply to healthy men at average risk for disease. If you have increased risk because of your family history, health habits or clinical abnormalities, you’ll need more testing and care. And, in each case, you should discuss options with your doctor so you can decide what’s best for you.

The 20s

Pediatricians and parents are in charge of tests for children and teens. But by age 20, men should take the wheel. And part of their new responsibility is to schedule regular checkups with a primary-care physician. As a rule of thumb, men should have a complete physical every five years when they are in their 20s, every three years in their 30s, every two years in their 40s, and every year beyond age 50.

Although cardiovascular diseases surface in midlife and beyond, risk factors start to do their damage in youth. Age 20 is the right time for a complete cholesterol profile and a careful blood-pressure check. It is also the time to measure height and weight, and to use these numbers to calculate your body-mass index, or BMI, the standard measure of obesity.

These tests should be repeated at every complete physical (and more often if abnormalities are detected or symptoms develop). Although the evidence of benefit is less clear, most physicians also order a complete blood count, a blood-sugar test and a urinalysis at each checkup. And dentists also practice prevention; see yours every six to 12 months.

As a rule, medical tests pile up as the years pile on. Testicular-cancer screening is the exception. It’s a young man’s disease, so men should have a physician’s exam at every checkup until age 35, and they should also examine themselves at regular intervals, perhaps monthly (ask your doctor for information on self-exams). Men should also get an adult-type tetanus-pertussis-diphtheria booster every 10 years; so, for men who have all their pediatric shots, the first will come in their 20s.

The 30s

Routine medical tests in the 30s simply continue the pattern of the 20s, just decreasing the interval between checks to three years and saying good riddance to testicular exams at age 35.

The 40s

Medical care gets more complex in your 40s—but only a little. Most physicians schedule a baseline EKG to test your heart function at about age 40, and then repeat it periodically. And the American Diabetes Association recommends a fasting blood-sugar test at age 45, then every three years. It’s also a reasonable time to start skin-cancer screening, with periodic self-exams, a physician exam with each checkup, and exams by a dermatologist for men at high risk (like those with fair skin, a family history of skin cancer, or who’ve had severe sunburns).

The 50s

Now it starts to get interesting. Along with “all of the above,” turning 50 means adding four more items to your medical checklist:

  1. Colon-cancer screening. Men at average risk can choose from four options: an annual fecal occult blood testing (FOBT) with colonoscopy for a positive test; a FOBT plus sigmoidoscopy every five years; a colonoscopy every 10 years; or a double-contrast barium enema every five to 10 years. Individuals at higher-than-average risk (like those who have had previous colon polyps or colon cancer in a parent or sibling) should choose colonoscopy; it’s the most arduous test but also the best. 2. Prostate-cancer screening. Colon-cancer screening is a no-brainer; every man should have it, though each can decide which type to have. But prostate-cancer screening is controversial. It is surely the best way to detect prostate cancer in its earliest, most-treatable form. Still, it is far from certain that early treatment will prolong life, and for some men the side effects of treatment will be worse than the illness, which is often very indolent. Annual PSA blood tests and digital rectal exams should be offered to men starting at age 50 (or at 40 or 45 for African Americans, or men with fathers or brothers with prostate cancer). Doctors should discuss the pros and cons of screening with each patient, who then has the burden of deciding for himself. Testing is unlikely to be helpful beyond age 70 to 75. 3. Eye exams by a specialist every one to two years, starting at age 50. 4. An annual flu shot.

The 60s

In terms of medical tests and treatments, a 60-year-old is just a grayer 50-year-old, with two exceptions. Men who have ever smoked, even just 100 cigarettes, should get an abdominal ultrasound test to look for an abdominal aortic aneurysm (AAA) at age 65 (a family history of AAA is another reason to get the test). And all men should roll up a sleeve for a pneumococcal pneumonia shot at age 65.

The 70s and Beyond

In time, even the healthiest of us will experience diminished physical and mental abilities. With good health habits, good medical care, good genes and good luck, the decline will be gradual—but it will occur. While it’s important to keep working to stay healthy and active, it’s also important to understand, accept and adjust to new limitations. But that doesn’t mean dwelling on what’s been lost. Instead, focus on all the good things in your past and keep looking for good things in your present—and future.

One of the few entirely good things about becoming an octogenarian is that you’ll need fewer routine screening tests. Prostate-cancer screening is downright foolish, and many doctors believe the value of colon-cancer screening diminishes as the years roll on.

If you’ve made it to your 90s in good shape, your wisdom and experience are likely to include the value of good health habits and preventive medical care. Although it’s impossible to single out any one bit of advice, the American aphorist Mason Cooley did a pretty fair job in 1922: “The wisdom of age: Don’t stop walking.”

Harvey B. Simon, M.D., is an associate professor of medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the editor of Harvard Men’s Health Watch, a monthly newsletter, and the author of six consumer health books, including “The Harvard Medical School Guide to Men’s Health” (Simon and Schuster, 2002) and “The No Sweat Exercise Plan. Lose Weight, Get Healthy and Live Longer” (McGraw-Hill, 2006).