Dear Doctors: Our family spends a lot of time these days on our screens. I’ve always had trouble sleeping (mom brain), but now my husband and our two teen boys are struggling, too. Do you think all the screen time could be why?

Dear Reader: We’re all dealing with so much right now -- stress, anxiety, isolation and uncertainty -- that poor sleep has evolved into an epidemic of its own. And with a large portion of our daily lives taking place online, it’s quite possible that the high-energy light emitted by our computers, tablets and smartphones is adding to the toll.

For many of us, the work day, the school day and even socializing have shifted online. Add to that the hours we were already spending on our screens before the pandemic, and many of us are getting the highest daily doses yet of what’s known as “blue light.”

Similar to sunlight, blue light has been shown to suppress the release of melatonin, a hormone produced by the pineal gland in the brain that makes you feel sleepy. Recent studies have found that prolonged exposure to blue light, particularly in the hours before bed, confuses the brain. Instead of the warm tones of evening light, which signal the brain to power down and prepare for sleep, the blue light emitted by electronic devices insists it’s daytime.

This affects not only the ability to fall asleep, but also to stay asleep and spend adequate time in the various stages of sleep -- especially the all-important deep sleep. That’s a serious problem, because lack of high-quality sleep not only leaves us tired in the short term, it also is associated, over time, with more serious health issues. These include headaches, weight gain, diabetes, high blood pressure, coronary heart disease and depression.

The good news is that you can take specific steps to mitigate the effects of exposure to blue light and improve your ability to fall asleep and stay asleep. One cornerstone of good sleep hygiene is a consistent bedtime. Decide on what your bedtime will be, then end all screen use at least two hours -- and preferably three hours -- before then. If you don’t build in that no-screen buffer, the blue light will continue to tell your brain that it’s broad daylight. This, in turn, confuses your inner clock, which throws off your ability to fall asleep.

In that same vein, block the various digital lights that can populate the bedroom, such as clock dials, smoke alarms and other electronic devices. When it comes to working with a computer or tablet, consider purchasing special filters, which reduce the amount of blue light that a device emits. Protective eyewear that blocks blue light is also available.

Quite a few manufacturers now include a special “night mode” option for smartphones, computers and tablets. When activated, night mode shifts the light emitted by the screen from the high-energy blue light to the warmer end of the spectrum. This all takes planning and discipline, but, considering the stakes, it’s worth it.

(Send your questions to askthedoctors@mednet.ucla.edu. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I’ve been working from home for six months, so no more bike commutes and no office staircases. My two young kids are home, too, which means I can’t do a lunchtime bike ride, or even go during a break. How bad is it that I’m sitting way more than ever?

Dear Reader: We wish we had better news, but, yes, prolonged sitting is bad for your health. The long stretches of sitting required by so many modern jobs are putting people at risk of a number of adverse health effects. This includes weight gain, obesity, increases in abdominal fat, high blood pressure and Type 2 diabetes. Taken together, these factors are associated with an increase in the risk of cardiovascular disease and cancer, as well as early death. Add in the mental health side effects of prolonged inactivity, such as depression and anxiety, and it’s easy to see how the term “sitting disease” came about.

It wasn't all that long ago -- historians point to the Industrial Revolution -- that we humans began to sit down for extended periods. Prior to that, staying fed, clothed, housed, protected and entertained kept us moving. With more than 600 muscles in our bodies, it’s what we’re literally built to do. This includes walking, running, reaching, climbing, stretching, swimming, twisting, crawling, jumping, bending and lifting throughout long and mostly active days. And while disease, hunger and hardship took their toll in the agrarian world, it does seem that with increasingly sedentary work and play, we’ve now traded one set of health problems for another.

Today, only two out of every 10 workers have active jobs, a decrease of about 80% since 1950. Between desk work, passive transportation and the increasingly sedentary nature of entertainment and play, many people stay seated for at least 10 hours each day. That’s the number research associates with a marked increase in cardiac risk.

All of which means that, even during the pandemic that’s robbed us of our normal lives, we need to get creative and get moving. Fortunately, it doesn’t take much. A study that tracked the mortality rate of 8,000 adults aged 45 and older for four years found that trading 30 seated minutes for the same amount of moderate or vigorous activity lowered the risk of early death by 35%. This joins previous research that pegged duration of sitting -- an hour or more at a stretch -- as a risk factor. People who sat for 30 minutes or less at a time had the best outcomes.

So do your heart, lungs and metabolism a favor and work regular movement into your day. Set a timer to walk a few minutes every half-hour. Get some hand weights and lift throughout the day. Get your kids involved, too: Run and jump and stretch, chase each other around the house, have parades, enjoy moments of planned chaos, take walks together, do yoga, practice deep breathing, ride bikes. Make it a goal to work movement into your family’s daily life, and your body and your kids (and your family doctor) will thank you.

(Send your questions to askthedoctors@mednet.ucla.edu. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: My daughter is overdue for her second shot of the HPV vaccine, but I’m hesitant due to the pandemic because I want her immunity to be strong right now. Are you recommending people get this vaccine during COVID?

Dear Reader: The short answer is yes, we strongly encourage everyone to receive all of their routine vaccinations at this time, including the series for the human papilloma virus, also known as HPV. Although vaccines work by interacting with the immune system, each one is specific to a certain infectious agent. The HPV vaccine creates antibodies to the human papilloma virus. That means it will not interfere with the immune system’s ability to respond to the coronavirus that causes COVID-19.

The human papilloma virus refers to a large group of related viruses. Most cause warts on various parts of the body. The viruses are divided into low-risk types, which are rarely dangerous, and high-risk types, which can develop into cancers. These include cervical cancer, cervical precancer, certain throat cancers, anal cancer and cancers of the penis, vulva and vagina.

Taken together, HPV infection causes up to 40,000 cases of cancer each year. This includes 11,000 cases of cervical cancer, which cause 4,000 deaths each year. Cervical precancer, which means abnormal cells are present on the cervix, affects almost 200,000 women each year. Treatment to prevent more advanced cases of cervical precancer from progressing to cancer include cryosurgery or laser therapy to freeze or burn away the cells. These treatments can limit the patient's future ability to have children.

The good news is that the HPV vaccine, which was introduced in 2006, is extremely effective at offering protection from the virus. Widespread vaccination could prevent more than 90% of cancers that are now caused by HPV. Younger patients between the ages of 9 and 14 will be protected by two doses of the vaccine, with the second dose given six to 12 months after the first. Three doses are recommended for individuals between the ages of 15 and 24, with the second dose given two months after the first and the third within six months of the first. It can be a little confusing, but your health care provider will advise you on the optimal schedule for each child according to their age.

We heard from another reader, who asked us to discuss HPV and colon cancer. Although the role of HPV in anal cancer is well-established, a potential link to colon cancer has been a source of controversy. That may be changing. A study published by the National Institutes of Health found HPV infection is common in patients with colorectal cancer. The study reported that HPV infection was often found in colorectal cancer tissues, as well as tissues adjacent to the cancers. Analyses of data in Europe, Asia and South America also found a higher incidence of colon cancer among individuals infected with HPV. With a recent increase of colon cancer among younger adults, research into a potential link is increasing and may soon lead to a more definitive answer.

(Send your questions to askthedoctors@mednet.ucla.edu. Owing to the volume of mail, personal replies cannot be provided.)