7 Numbers That Could Save Your Life

3. Blood sugar

Why it’s important: If your blood sugar levels are too high, that means your body doesn’t make enough insulin or can’t use it as well as it should. Over time, if diabetes is not treated, the extra glucose in your blood can cause serious health problems like heart disease, stroke, kidney failure, vision loss and nerve damage, which can lead to amputations. 

If your blood sugar drops too low, that can also be dangerous, says Ardeshir Hashmi, M.D., section chief of Cleveland Clinic’s Center for Geriatric Medicine. Adults in their late 70s and 80s tend to be at higher risk because they may not be eating and drinking as much. A drop in blood sugar can cause confusion, dizziness and falls.

Goal: Fasting plasma glucose level of 70-99 mg/dL or an A1c level less than 5.7 percent. The A1c test measures the glucose in your blood over the last three months, while the fasting glucose test is a one-time look.

How to test it: Both your fasting plasma glucose level and your HbA1c can be measured with a blood test. If you’ve been diagnosed with diabetes, your doctor may ask you to check your sugar levels at home with a glucose meter or a continuous glucose monitor.

Smart strategies: Making healthy lifestyle changes is once again your best bet. Research shows a low-carb diet is especially effective at lowering glucose levels, Hashmi says.

Aerobic exercise is also important, he says. Studies show exercise lowers blood sugar levels over time, reduces insulin sensitivity and contributes to weight loss. Hashmi says exercising regularly is more important than how hard you exercise in each session.

If you’ve been diagnosed with diabetes, your doctor will work with you to create a personalized plan that includes monitoring your blood sugar levels, making dietary changes and possibly taking medication. (For more, see 7 Simple Ways to Lower Your Blood Sugar.)

4. Hearing number

Why it’s important: This newly named metric, technically called a four-frequency pure tone average (PTA), measures how loud speech must be for you to hear it. The number can range from zero to 100 decibels (dB) and can help you better understand your hearing, says Frank Lin, M.D., director of the Cochlear Center for Hearing and Public Health at Johns Hopkins University and coauthor of AARP’s Hearing Loss for Dummies.

The higher the number, the louder sounds need to be for you to hear them.

Lin and his colleagues at Johns Hopkins are encouraging greater use of the number because it offers data on how your hearing changes over time. Traditionally, audiologists diagnose you within more general categories of mild, moderate or severe hearing loss.

“Hearing, for a lot of people, is still this black box,” Lin says. “This is one number that can summarize your audiogram.... You can track your hearing across your lifetime and act on it.”

Hearing loss isn’t just about being able to hear your loved ones or your favorite show on TV. The latest research shows it’s closely linked to other aspects of health, including cognitive decline, social isolation, depression and lower quality of life.

Goal: Under 20 decibels

How to test it: If you’ve had a hearing test from an audiologist, you should have a hearing number, or PTA, Lin says. And two iPhone apps — offered by Mimi Technologies and Jacoti Hearing Center — provide a free test that will give you your number, Lin says. (Both companies sell products, but the test and apps are free.) Johns Hopkins researchers are developing a similar app for Android smartphones. AARP members can also take a free at-home hearing test using their phones; the results of the 10-minute test are reported as being in the normal range, slightly below or substantially below normal.

Here are the ranges for different levels of hearing loss defined by the National Institutes of Health:

• Mild: 20-40
• Moderate: 41-60
• Severe: 61-80
• Profound: 81+

Smart strategies: If your hearing loss is mild or moderate, you may want to consider one of the over-the-counter hearing aids now available, Lin suggests. Research shows they can be as effective as one you would get from an audiologist, and they tend to be significantly more affordable.

For more severe hearing loss, a prescription device may be needed, or even a cochlear implant. (For more on this, read: How to Shop for an Over-the-Counter Hearing Aid.)

5. Waist circumference

Why it’s important: Belly fat is linked to a higher risk of other serious conditions, including stroke and type 2 diabetes.

Measuring your waist is an easy way to get an idea of how much body fat you have, and that’s a key factor in assessing your health and your risk of chronic illness. Both the World Health Association and the American Heart Association recommend using waist circumference to screen for risks like heart disease and diabetes. Plus, research shows that belly fat — also called visceral fat — is more harmful for your health than fat that accumulates in other parts of the body. “There’s a very direct correlation," Hashmi says. "The more fat there is in that area — the [higher] your waist circumference — the more likelihood there is of you getting a heart attack.”

Goal: Under 35 inches for women, and under 40 inches for men

How to test it: To measure your waist circumference, place a tape measure around your middle, just above your hip bones. Make sure it’s snug but not compressing your skin. Take the measurement just after you breathe out. 

Smart strategies: Your best bet to shrink your waist is to switch to a healthier diet and consume fewer calories while also moving more. Hashmi says cutting down on carbs can be particularly helpful. “Carbohydrates in the diet are the ones that go and sort of settle around our tummies,” he says. 

When it comes to exercise, abdominal exercises can help strengthen your core, but they won’t make that belly fat disappear. Instead, experts recommend upping your overall physical activity. Research shows that both aerobic activity and strength training are key to burning abdominal fat. Aim for 30 to 60 minutes of moderate exercise a day.

Even if the scale doesn’t budge, getting more active will still help reduce the amount of dangerous visceral fat in your gut, studies show. (See: How to Lose Belly Fat After Age 50.)

6. Bone density

Why it’s important: Knowing your bone density is important because it measures how strong your bones are, alerting you if you have a higher risk of osteoporosis, falling and fractures.

Fractures, particularly hip fractures, can be dangerous for older adults, often leading to a loss of independence and even death. Research shows that just a 10 percent loss of bone mass more than doubles your risk of a hip fracture.

“All women should be screened for osteoporosis at age 65,” says Laura Calvi, president of the American Society of Bone and Mineral Research and professor of medicine at the University of Rochester. 

You should also request a scan if you’re younger and you’ve broken a bone from a minor accident, like falling from standing height, or if you have other risk factors, Calvi says. Men should be screened at age 70 or 75. (Read: Should You Get a Bone Scan?)

Goal: T score above -2.5 (compares your bone density with that of a healthy young adult of your gender) or Z score above -2.0 (compares your bone mass with that of other people of your gender, age and size)

How to test it: There are three types of bone density tests. The most common, a DEXA scan, is a low-dose X-ray that measures calcium and other minerals in your bones.

Smart strategies: Make sure your diet includes enough calcium and vitamin D, the two most important bone-building nutrients, or consider a supplement. The National Institutes of Health’s Office of Dietary Supplements recommends at least 1,000 mg of calcium and 600 international units (IU) of vitamin D a day for adults, and higher amounts for those over age 70. (For ideas on how to get vitamin D from your diet, read: 7 Foods High in Vitamin D.)

Studies show that physical activity — both cardiovascular exercise and strength training — helps to strengthen bones.

If you already have osteoporosis, different treatments and medications are available to help strengthen your bones and lower your risk of a fracture, Calvi says.

7. VO2 max

Why it’s important: VO2 max measures how much oxygen your body can consume during exercise, and as a result, it provides a critical indicator of an individual’s overall fitness level, says Art Weltman, a professor of kinesiology and medicine at the University of Virginia.

“Individuals that have higher maximal oxygen tend to have, by definition, higher levels of fitness,” Weltman says. “And there is a relationship between fitness and a whole host of health-related outcomes.”

Some experts believe a high VO2 max score is the strongest predictor of a longer life span.

Goal: There are no strict targets for VO2 max, but the American College of Sports Medicine publishes benchmarks for men and women by age. For example, a VO2 max of 35.5 is considered “good” for men ages 60-69, while 30.0 is “good” for a woman in the same age group. 

Weltman says the key is to focus on improving your own score, aiming to surpass the average for your age.

So if you are 70 and your VO2 max is at the 85th percentile, you may be chronologically 70, but from a physiological perspective you have the average fitness level of a 50-year-old, Weltman says. “You can get a sense of where you are relative to individuals of your own age and sex, and where you fall across the spectrum of fitness.” 

How to test it: VO2 max testing usually takes place in exercise labs or specialized fitness centers. The test requires you to wear a mask while you run, ride a bike or use a rowing machine, with exercise intensity gradually increasing.

For a simpler alternative, many wearable fitness trackers now estimate your VO2 max using your heart rate and other data. Those estimates are typically less precise than the lab-based tests, Weltman says, but can give you an idea of where you stand and serve as a motivation tool.

Smart strategies: Of course you should exercise regularly, but Weltman says the best way to boost your VO2 max is to incorporate some higher-intensity activity. Weltman suggests high-intensity interval training (HITT), which incorporates brief bursts of very intense exercise followed by periods of slower, less-demanding work.

When you’re exercising at high intensity, “it should be difficult to talk,” Weltman says. “You’re breathing a little bit heavy, and you should perceive that the work is hard for you.”