As we adhere to strict physical distancing measures to slow the spread of COVID-19, most of us are also spending more time indoors. This means more time spent in “biological darkness” – although indoor lighting may appear adequate, the intensity is so low that our body’s circadian system perceives it to be nighttime. This can send confusing signals to our brain, negatively impacting our sleep, well-being, and health.
Why is it important to maintain a healthy circadian rhythm?
Our circadian rhythms regulate our sleep-wake patterns: how energic we feel during the day, how alert and productive we are at work, how well we sleep at night.
A healthy circadian rhythm and proper sleep are crucial not only for our mental well-being but also for our physical health, including our immune system functioning. Sleep not only reduces our risk for infection but can also improve outcomes once we are infected. This has been cleverly shown in experiments where participants were exposed to the rhinovirus, a common cold virus. Participants who reported less sleep had a greater chance of subsequently developing symptoms of the common cold.
Four strategies for maintaining a healthy circadian rhythm while quarantined
- Seek morning light. The most important regulator of our circadian clock is light. When we don’t get enough daylight, our circadian clock drifts later. We become night owls, which makes it difficult for us to wake up in the morning when the alarm clock rings. Light also has direct effects on mood-regulating regions in the brain. Seek as much natural daylight as possible: go for a daily walk, jog, or bike ride (at a distance from others); eat on your balcony; work next to a window. Even on a cloudy and rainy day, the brightness from outdoor light far exceeds ordinary home lighting (generally below 300 lux, compared to 100,000 lux on a sunny day). Morning light is especially important for our sleep and mood. If your time is limited, choose outdoor activities in the morning rather than later in the day. If you can’t go outside, consider light therapy. Choose a lightbox that is 10,000 lux at a comfortable distance (14-18 inches) from the eyes. Depending on the person, 15-60 minutes of morning light therapy should be sufficient, ideally within the first two hours after waking up.
- Dim your lights at night. While we need light during the day, light at night disrupts our circadian rhythms and sleep by suppressing melatonin secretion. This effect is amplified the less time we spend outside in daylight. Dim your lights at night, starting three hours before going to bed. Block out blinds are a great way to darken your room, especially in the summer months. Exposure to screens should also be limited three hours before sleep, including smartphones, tablets, laptops and close-range TVs. Software that blocks blue light emitted from screens at night can be helpful.
- Avoid caffeine after 3pm. While coffee helps beat fatigue, a significant amount stays in your system for over 6 hours, which can make it harder to fall asleep at night, reducing total sleep time.
- Have a routine. Structure the day according to a regular schedule. Maintain a regular bedtime, wake-up time, and meal timing. Also, keeping a regular daily exercise schedule, preferably in the morning, may help keep your circadian rhythms on track.