Dear Doctor: I’m 44 years old, and after wearing high heels to work for the last 20 years, I’ve lost flexibility in my feet. It also seems to be affecting my balance. Can you recommend foot exercises that can help?

Dear Reader: Considering the important work they do, our feet don’t get the attention they deserve. And yet, these complex systems of muscles, bones, tendons and ligaments form the base from which we balance, bear the full weight of our bodies and carry us through the thousands of steps in our daily lives.

One of the best things you can do for your feet is to give them a break from high heels, even just for a few days per week. Not only do high heels shift you forward and force your full weight onto the balls of your feet, they prevent you from properly using the muscles of your feet (and your legs) as you walk. Speaking of which, one of the best exercises for getting feet into shape is exactly that -- walking. Get a pair of supportive and flexible athletic shoes, and take a stroll. Be conscious of rolling through the foot, heel to toe, in a deliberate but natural motion. Don’t be surprised if this feels strange or even awkward at first. We tend to treat our feet as solid blocks rather than the intricate and articulated wonders that they actually are.

When it comes to a specific foot workout, exercises that take just a few minutes a day can make a difference.

-- Toe lift: Stand barefoot and, without straining, slowly and gently raise all 10 toes off the floor. Hold for a few seconds, then lower again. When you’re comfortable with this move, add some more repetitions, this time fanning your toes apart as you lift and lower them.

-- Heel lift: Engage your calf muscle and gradually raise your heel so that you balance on the ball of your foot. Hold for a few seconds, then gently lower again. If your ankles are strong, you can slowly and deliberately roll the ball of your foot from side to side and in a circular motion, which engages a range of muscles and -- bonus -- gives a nice massage. This exercise can be done either seated or standing.

-- Toe point: Extend your leg and, in a fluid motion that starts at the heel and rolls through the arch and down to the toes, gently extend your foot. Point your toes, hold for a few seconds, and then reverse the movement until you’re flexing your heel.

-- Toe dome: Standing barefoot, gently grip the floor with all five toes of each foot, as though you’re going to pick up a dollar bill. You’ll form a small dome when you’re doing this one right. Hold for a few seconds and then release.

Don’t try to do too much all at once. Work your way up to eight to 10 repetitions of each exercise. With just five minutes a day, you’ll soon regain strength and flexibility, and your feet will thank you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I had a coronavirus test, and it was negative. Then I had the antibody test, and I was surprised when it came back positive because I hadn’t been sick. How do these coronavirus tests work? Are they accurate?

Dear Reader: There are two testing goals related to SARS-CoV-2, the coronavirus that causes COVID-19. One is to learn whether or not you are currently infected. The other is to see whether or not you have been infected in the past.

By far, the most common test being conducted at this time is for the coronavirus itself. This involves the use of a nasal swab, which is a long, thin stick with soft brushlike material on the tip. The swab is carefully inserted deep into the nose, to the passageway that connects to the back of the throat. (It’s uncomfortable, but not painful.) The goal is to gather a sample that includes cells and secretions from the back of the throat and from all along the length of the nose. Although there’s a less-invasive COVID-19 test that relies on just a throat swab, similar to the test used for strep throat, it’s not considered to be as accurate as the nasal swab. A newly developed saliva test, which requires just a sample of spit and returns a result within 30 minutes, has been submitted for regulatory review. Each of these tests look for genetic markers specific to SARS-CoV-2. Meanwhile, on July 3, the Centers for Disease Control and Prevention announced the development of a single test able to diagnose influenzas A and B as well as the novel coronavirus.

When you become sick with a virus, the immune system sends specialized proteins known as antibodies to mount an attack. Since antibodies are specific to the invader they are fighting, it’s often possible to identify when someone’s immune system has fought off a particular pathogen. It usually takes at least one week, and can take up to three weeks or longer, for the body to develop antibodies. Although it’s rare, despite being infected by a pathogen, some people don’t develop antibodies at all.

An antibody test is performed by screening a blood sample for specific markers of the antibody in question. Unfortunately, in the case of the novel coronavirus, the accuracy of these tests is in question. The CDC has found that up to half of antibody test results may be inaccurate, giving either a false positive or a false negative. A recent study examined 40 different types of antibody tests and found a wide disparity in their accuracy. The researchers suggested that until these tests are improved, people should not rely on the results.

As for having antibodies to SARS-CoV-2 despite not having been physically ill, that’s entirely possible. A hallmark of this virus is that some people, despite being infected, don’t develop symptoms. However, they can still pass along the virus, which is known as asymptomatic transmission. That’s why, in order to protect the people around us, it’s so important for each of us to wear a face covering in public, social distance and wash our hands.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My 36-year-old son has recently been diagnosed with primary lymphedema. He has developed open wounds on both of his legs and is in a lot of pain. The condition limits his movement, and he has become depressed. Can you provide information about treatment, and where to seek it?

Dear Reader: Lymphedema is chronic and progressive swelling that occurs because the lymphatic system, which is part of the immune system, isn’t working properly.

The lymphatic system is made up of a network of minute, thin-walled tubes known as lymphatic vessels, and by hundreds of lymph nodes, which work together to carry and filter lymph throughout the body. Lymph is a clear fluid, rich in white blood cells, which helps fight infection and transport waste, toxins and debris. If you’ve ever had a scrape and seen a clear, watery fluid seep out of the wound, that was lymph. Unlike the blood circulatory system, which uses the force of the heartbeat to propel blood, the lymph system is largely dependent on muscle movement to keep things flowing. When either the lymph vessels or the lymph nodes become damaged, lymph begins to back up in that part of the body and causes swelling.

Swelling that arises due to lymphatic injury or obstruction is called secondary lymphedema. It’s often seen in cancer patients whose treatment involved the surgical removal of lymph nodes. Swelling that occurs independent of surgery or other damage, as in your son’s case, is known as primary lymphedema. It’s a rare inherited condition in which the lymphatic vessels are not properly formed and can’t carry out their task.

There is no cure for lymphedema at this time. Instead, the focus is on managing the condition. This includes specialized massage to help with drainage, the use of compression garments, light exercise focusing on muscle contraction to encourage lymph movement, limb elevation and pneumatic compression.

An effective treatment approach known as complete decongestive therapy, or CDT, which originated in Europe and Australia, is now becoming popular in the U.S. It combines a number of lymphedema therapies into a comprehensive program that focuses on swelling reduction, maintenance and self-care. Although your son will benefit from lymphedema treatment, your first priority is helping him get appropriate wound care. Due to swelling and skin tension, patients with lymphedema are at high risk of having a nick or a scratch develop into an open wound. If there’s a wound clinic in your area, the health care providers there can initiate treatment and teach you and your son how to care for the wounds at home. Your family doctor can help as well.

Lymphedema is a complex and challenging condition, so it’s important to seek out someone with expertise in the condition. Most cancer centers and hospital-based cancer programs offer lymphedema support or therapy, and can often provide referrals. Two organizations, the National Lymphedema Network (NLN) and the Lymphology Association of North America (LANA), oversee certification programs for lymphedema therapists. They also offer excellent resources, including directories of therapists. You can find them at lymphnet.org and clt-lana.org.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)