Dear Doctor: It seems like a coronavirus test you can do at home would be really helpful. Then people who don’t have symptoms could know that they should quarantine, and maybe that would help stop the spread. Is there anything like that on the horizon?

Dear Reader: Not only are home coronavirus tests already a reality, the U.S. Food and Drug Administration has just issued an emergency use authorization for the first rapid coronavirus self-test that will be available without a prescription. This test, called the Ellume COVID-19 Home Test, got the nod from the FDA on Dec. 15, 2020. It joins the Lucira COVID-19 All-In-One Test Kit, a prescription-only home test, which the FDA approved last November. It is expected to become available in 2021, and will reportedly sell for about $30. Both tests utilize a nasal swab.

The over-the-counter home test has been authorized for self-use by people who are 16 years and older. Those individuals may then administer the test to people under the age of 16, including to children as young as 2 years old. The reason for the age limitations is to assure that the person is able to accurately perform the multiple steps needed to complete the test.

Although not as accurate as lab-based tests, Ellume’s test still got high marks. In a clinical study of almost 200 people, the test detected 95% of the infections found by the lab-based test. Another advantage of the new test, in addition to not requiring a prescription, is that it can be used by people who do not have symptoms of COVID-19. However, in asymptomatic cases, studies showed that the rate of accuracy dropped to 91%.

If you do take a home test and get a positive result, it’s time to self-quarantine. Mild-to-moderate symptoms of COVID-19 can be managed at home. However, if breathing becomes compromised, it’s important to seek immediate medical care.

While the increasing availability of home coronavirus tests is a big step forward in controlling the spread of the virus, it’s important to note that they are just one part of a multi-prong approach. It’s still important to wear a good mask whenever you’re outside of the home, particularly when you’re indoors. Remember that your mask not only protects others from your exhaled breath, but it also offers a degree of protection to you as well. Continue to avoid gatherings of people outside of your core group, maintain social distancing when in public, and remain vigilant about hand-washing and keeping high-touch surfaces clean.

It’s only when taken together that these precautions offer the best protection. A great metaphor that we heard recently is to think of each precaution as a slice of Swiss cheese. When you look at them one at a time, the slices of cheese have holes. But when you pile the slices up on top of each other, they act together to form a barrier. Each coronavirus precaution has its weakness, but they don’t all have the same weakness. So, by adhering to all of the precautions, you’re compensating for the various shortcomings and giving yourself the best chance at avoiding infection.

(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 gym has been closed for months, so I’ve been doing online workouts during the pandemic. A guy in our session keeps talking about something called “fasted cardio,” and how it’s helping him lose fat and gain muscle. What is it? Does it really work?

Dear Reader: The term fasted cardio refers to doing a heart-pumping workout after not eating for a stretch of time long enough to be considered a fast. Often, it’s overnight, which means anyone who has gone for a run or taken a dance class before grabbing breakfast can say they’ve done fasted cardio.

The logic behind the practice lies in the way that our bodies use stored energy. The body’s top choice when it needs energy is glycogen, a form of sugar that is stored in the muscles and the liver. It’s made up of multiple linked glucose molecules, the simple sugars in our blood that are derived from digestion. The body can burn either sugar or fat for energy, but using sugar is both faster and easier, so it uses that first. However, glycogen stores are finite, which is where fasted cardio comes in. The idea is that by the time you’ve gone 10 or 12 or more hours without eating, your body will have worked its way through a good portion of its existing glycogen stockpile. And, since those glycogen stores haven’t yet been replenished with a meal, the body will then be forced to turn to Plan B during your workout, which is to also burn stored fat.

The catch is that, despite the appealing and simple logic, the research into fasted cardio is scant, and the results have been mixed. A study from 2017, which analyzed research into the practice, didn’t find the promised changes to body composition. Another drawback is that, when in a fasted state, the body has another energy option besides fat to make up for the lack of glycogen. We’re talking about protein, with the source being your own muscle tissue. Losing muscle mass is the opposite of what you’re trying to achieve. And, while the big picture of how the body uses energy appears straightforward, it’s actually quite complex. At any given moment, processes such as hormone secretion, enzyme activity and gene activation -- to name just a few -- play a decisive role in fat metabolism. So does the type and duration of the exercise you’re engaging in.

All of which leads us back to our familiar refrain when it comes to diet and exercise. That is, moderation and consistency. Eat a healthy diet, steer clear of junk food and simple carbs, do a mix of aerobic exercise and strength training, and get enough sleep. These will serve you better than trying to game the system with a tricky diet or exercise routine.

For those of you who decide to give fasted cardio a try, be sure that you’re still drinking plenty of water. And don’t forget to eat a balanced breakfast after you’ve finished working out.

(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: A few years ago, you had a column about why it’s important to know CPR. My boyfriend took the Red Cross class, and he actually ended up helping someone once. But what about now, during the pandemic? Is it safe to give or get CPR?

Dear Reader: Considering that a main avenue of transmission of the coronavirus that causes COVID-19 is believed to be respiratory droplets from an infected person, your question about CPR is a timely one.

For anyone unfamiliar with CPR, which is short for cardiopulmonary resuscitation, it’s an emergency procedure performed when someone’s heart has stopped beating. This can occur for many reasons, including heart attack or cardiac arrest due to near-drowning, an extreme allergic reaction, asthma attack, smoke inhalation or poisoning. When initiated at the start of a medical emergency, CPR can double, or even triple, someone’s odds of survival.

The process is made up of three distinct components. First, call 911 and report the emergency. The other two elements of CPR are chest compressions, which are performed on the sternum in a specific rhythm, and mouth-to-mouth rescue breathing. The challenge during the pandemic is the proximity that is required to perform CPR. The rescuer is literally on top of, and just inches away from, the person they are helping. Even without the element of rescue breathing, an exchange of breath during the CPR process is likely. Regarding rescue breathing, only someone who is formally trained in CPR should attempt it. And during the pandemic, the Red Cross advises against performing rescue breathing when COVID-19 is either suspected or confirmed.

This leaves chest compressions, which still put people into far closer proximity than the 6-foot distance guidelines we’re all trying to adhere to. To keep both parties as safe as possible from the airborne respiratory droplets or aerosols, the Red Cross has outlined specific procedures. The person performing CPR should wear as much personal protective equipment as possible. This includes respiratory protection, eye protection, disposable gloves and a disposable gown or covering of some sort. Although N95 masks are optimal, they remain in very short supply. A properly fitted mask made of multiple layers of fabric is an acceptable substitute. The person receiving CPR should be outfitted with a mask as well. If only one mask is available, the Red Cross recommends using it on the victim.

Part of performing CPR is assessing whether or not the victim has begun to breathe on their own. At this time, the Red Cross is asking rescuers to do a visual assessment rather than listening or feeling for breath. Taking this precaution can decrease the risk of transmission of the virus. People trained in CPR have been taught that using rescue breathing when cardiac arrest follows a breathing problem, such as choking, a drug overdose or near-drowning, often leads to a better outcome. However, due to the risk of viral transmission, it is now recommended that compression-only CPR be administered until paramedics arrive in response to your 911 call.

(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.)