Computers, smartphones, tablets, and other internet-connected devices have transformed our lives. Digital technologies enable us to generate, process, and instantly retrieve huge amounts of information. They allow us to communicate with people all over the world and give us 24-7 access to videos, music, games, and other forms of entertainment.
A 2021 report from marketing research company eMarketer reveals that in 2020, Americans spent an average of nearly eight hours per day on digital media. And a Pew Research Center survey reported that 31% of U.S. adults—and 48% of 18-to-29-year-olds—are online “almost constantly.”
This degree of digital engagement may keep us informed and, on some level, connected with others, and it certainly keeps us entertained. But it also has a dark side. Let’s look at the health impact of excessive screen time.
Screen Time & Your Vision
Any activity that requires intensive visual focus can lead to eye strain and fatigue. Symptoms include:
- Blurred vision
- Dry or watery eyes
- Itchy, red, or burning eyes
- Sensitivity to light
Prolonged reading, driving, writing, sewing, etc., are common contributors, but a new category has emerged in recent years: digital eye strain, also called computer vision syndrome.
Unfortunately, excessive screen time does more than cause eye strain. Staring at a screen for long periods also exposes you to wavelengths of light that, over time, may lead to more serious eye problems.
Blue Light Can Damage the Retina...
Blue light is a natural, high-energy wavelength of light that is present in sunlight as well as artificial light. As part of the sun’s full spectrum of light, daytime exposure is beneficial, even essential for our health and well-being.
The problem with digital devices is that the LED lights that illuminate them emit much more concentrated blue light than other sources, and close-up, prolonged exposure—at all hours of the day and night—can take a toll on your eyes.
Most blue light passes directly to the retina, the tissue in the back of the eye that sends images to the brain. The macula, an area of the retina that is responsible for central vision and fine detail, is particularly vulnerable. Excessive blue light exposure is a recognized risk factor for macular degeneration, which is a leading cause of age-related vision loss.
...And Disrupt Your Sleep & Circadian Rhythm
Equally important are the effects of blue light on sleep. Any source of light dampens the natural nighttime secretion of melatonin, the sleep hormone, but research reveals that blue light’s effects on melatonin last twice as long as other wavelengths.
This disturbs not only your sleep but also your circadian rhythm—the genetically programmed biological clock that orchestrates normal 24-hour fluctuations in hormones, heart rate, blood pressure, and other physiological functions. Circadian rhythm disruptions are linked with an increased risk of inflammation, hypertension, obesity, diabetes, heart disease, depression, memory problems, and some types of cancer.
The effects of too much screen time go beyond blue light. When you stay up late texting, watching videos, or on social media, and you keep your phone by your bedside all night, you are developing poor sleep habits, which have negative repercussions on all aspects of your health.
Does Digital Technology Also Impact Cognitive Function?
Neuroscientists agree that digital technology can have a positive impact on brain function and behavior. Some computer programs and video games help improve memory, attention, reaction time, and learning skills. Others provide interventions that improve mental health.
However, the effects are not all positive. Excessive screen time has been linked with a shorter attention span and symptoms of attention-deficit hyperactivity disorder (ADHD). Dependence on social media and texting rather than more personal communication can increase feelings of isolation, and lack of real face-to-face interaction may impair social skills and emotional intelligence.
Pediatricians are particularly concerned about the effects of screen time on cognitive development and language acquisition in children, especially those younger than two. There is also increasing recognition that internet addiction—to video games, social media, online shopping, and more—is the real deal.
Other Health Effects of Too Much Screen Time
Additional health problems associated with extensive digital technology use include:
- Inactivity. The more time you spend online, plopped in front of a screen, the less time you are physically active.
- Weight gain. Decades-old research links excess TV viewing with weight gain, and digital devices have dramatically increased screen time.
- Tendonitis. “Phone thumb” or “texting thumb” is an increasingly common type of tendonitis (tendon inflammation and pain) caused by repetitive use of the thumbs.
- Back, neck & shoulder pain. Sitting for long periods hunched over a digital device promotes poor posture and may cause or exacerbate spinal or joint pain.
- Hearing loss. Listening to loud music, videos, or games via earbuds increases the risk of hearing loss over time.
- Injuries. Texting or using other distracting devices while driving, working, or walking is linked with motor vehicle accidents, workplace injuries, and falls.
Remedies for Excessive Screen Time
The most obvious antidote for “technology creep”—when digital devices take up more and more of your time—is to simply cut back. At the very least, do your eyes, brain, joints, and spine a favor and take frequent breaks.
Get up and walk around every couple of hours. Go outside, if possible. Exposure to sunlight enhances your mood, focus, and overall health, plus it is essential for optimizing circadian rhythms.
You may want to consider blue-light blocking glasses, which are available in prescription and nonprescription lenses, while working on your computer or other devices. Although the supporting research for these glasses is sparse and far from definitive, they may be helpful, especially if you spend a lot of time online.
Do your best to avoid digital screens an hour before bedtime. If you read on a tablet, turn on the device’s blue-light blocker or use the nighttime mode in the evenings. For additional support, take 1–3 mg of supplemental melatonin 30 minutes before bedtime to restore levels that are suppressed by blue light exposure.
I also recommend two nutrients that help protect your eyes and brain against blue light from digital devices. Lutein and zeaxanthin are carotenoids with powerful antioxidant and anti-inflammatory effects.
In the eyes, these carotenoids are concentrated in the macula, where they absorb and filter out blue light. Supplemental lutein and zeaxanthin are part of the Age-Related Disease Study (AREDS2) protocol for staving off the progression of macular degeneration. Studies reveal that boosting levels also increases macular pigment optical density (MPOD), resulting in enhanced retinal and macular protection, increased contrast sensitivity and visual function in bright lights, and reduced effects of glare.
Zeaxanthin and especially lutein, which is the most abundant carotenoid in the brain, support cognitive health as well. In addition to reducing oxidative stress and inflammation, supplemental lutein and zeaxanthin have been shown to increase levels of brain-derived neurotrophic factor (BDNF), a protein that enhances overall brain health. Small studies have reported improvements in performance on tests of memory, attention, and other markers of cognitive function after six months of supplementation.
You can get plenty of these carotenoids if you regularly eat spinach, kale, and other dark leafy greens, as well as egg yolks and yellow-orange produce. Unfortunately, most Americans get only 2 mg of lutein and zeaxanthin per day. That’s why I recommend supplements—a daily dose of 20 mg of lutein and 4 mg of zeaxanthin. This is especially important as we get older, as lutein and zeaxanthin concentrations in the eyes decline and risk of macular degeneration increases with age.