Why Are Some People Light Sleepers?

Does it seem like your partner could sleep through an earthquake, while the mere tick of a clock could wake you up? You’re probably a light sleeper. These are people who wake up easily around slight disturbances. On the other hand, heavy sleepers can snooze through loud noise and disruptive activity.

Various factors could cause these sleep differences, including genetics, hormone levels, and brain waves. However, researchers haven’t found a definitive cause as to why people sleep differently than others. Good quality sleep is important, so if you’re a light sleeper, keep reading. In this article, we’ll cover why some people are light sleepers, as well as some advice that could get you a better night’s sleep.

Different Sleep Phases

While we sleep, two important phases happen. Non-rapid eye movement (NREM) is a deeper sleep stage. Rapid eye movement (REM) is a dream phase where brain activity increases. Our eyes move rapidly without sending visual cues to the brain. We spend more time in NREM sleep, going through three cycles of deep sleep before we get to the REM stage. These are:

Stage 1 - NREM: This is the phase between full consciousness and sleep, lasting 5-10 minutes. The muscles become less tense, while breathing and heart rate slows down. The eyes are closed, but it is easy to wake up from.

Stage 2 - NREM: This is light sleep, when the body is preparing for deep sleep. This lasts from 10-20 minutes. Body temperature drops, eye movement stops, and heart rate and breathing become steady.

Stage 3- NREM: Also known as delta sleep, this is a deep sleep stage. It can last from 20 - 40 minutes. Outside noise or disruptions aren’t likely to wake people in this stage, but if they did, the person would feel tired and disoriented. The muscles are fully relaxed. Breathing, heart rate, and brain wave activity are at their lowest point. During deep sleep, the body starts to repair itself, while the brain stores any learned facts or memories. This stage is important, as enough deep sleep makes you feel refreshed the next morning.

Stage 4 - REM: During this stage, the brain’s activity is like how it acts when awake. The body is paralyzed, stopping you from acting out your dreams. Blood pressure, breathing, and heart rate increase again, while the eyes move rapidly in different directions. The first REM period lasts for 10 minutes, but gets longer while you sleep. You need to have been asleep for 90 minutes until you enter this stage.

Throughout the night, the body goes through this cycle again, around four to five times. However, light sleepers can stay in stage one or two, never reaching deeper or REM sleep. Deeper sleepers are the opposite, spending too much time in stages three and four.

What affects sleep stages?

If you’re a light sleeper, there may be a few factors that are affecting how you sleep. These are:

Age: As you get older, the time you spend in each sleep stage changes. Newborn babies can enter the REM stage as soon as they fall asleep. They can also spend up to 50% of their sleep in the dream stage. Elderly people spend less time in deep and REM sleep. They also wake up more during the night, sometimes up to 4 times.

Drugs & Alcohol: Drugs and alcohol can affect the quality of your sleep. Both prescription and non-prescription drugs can cause sleep issues. Alcohol can reduce the amount of dream sleep at the beginning of your cycle. However, as the night progresses, REM sleep becomes longer as the alcohol wears off.

Recent Sleep Quality: If you haven’t been getting enough sleep, or haven’t been sleeping consistently over a few days, this can cause irregularities in your sleep cycle.

Medical conditions: There are medical issues that can affect your sleep, such as sleep apnea, Restless Leg Syndrome, or narcolepsy. These can make you wake several times in the night, damaging your sleep cycle.

What’s the difference between a light sleeper and a heavy sleeper?

Sleep stages aren’t the only factor causing differences in sleep sensitivity, woman awake and cannot sleep

Sleep stages aren’t the only factor causing differences in sleep sensitivity. In 2010, researchers found they could measure a type of brain wave called sleep spindles. The research revealed that people who could produce more spindles could sleep better through disruptions. When a person generated more sleep spindles, it was less likely that loud noise, light differences, or strong smells woke them up.

The study also found that spindles were more active in the second sleep stage, the phase required to reach deep sleep. As light sleepers don’t have enough of these spindles, they are likely to wake up before the deep sleep stage. This could explain why they don’t achieve sufficient rest.

How to Get A Good Night’s Sleep

Unfortunately, you can’t fully control your sleep cycle or the number of spindles you produce. If you’re a light sleeper, this can be frustrating to hear, but there are measures you can take to get a better night’s sleep.

Make a bedtime routine. If you create a routine that you carry out regularly before bedtime, your body will start to associate those actions with rest. Avoid any stressful work or intense exercise. Instead, try and wind the body down with relaxing activities, like reading, having a bath, or meditating.

Stop using electronic devices before bed. Blue light emits from electronic devices, like smartphones, computers, and televisions. At night, blue light can be harmful, as it can affect melatonin production. Melatonin is a hormone that encourages your body to fall asleep. Try to stop using your devices half an hour before bedtime, and see if it makes a difference.

Assess your sleep environment. Look at your mattress, pillow, sheets, and duvet. If your mattress or pillows are unsupportive, you’re more likely to toss and turn at night. This can affect your quality of sleep. Similarly, make sure that your sheets are always clean and comfortable to sleep on.

Create a sleep schedule. Try to go to bed and wake up at the same time each day. This will help your body establish its circadian rhythm. Circadian rhythm is like an internal clock. It controls when you fall asleep and wake up. If you’re attempting to do this, remember to allow yourself 30 minutes to fall asleep.

In Summary

Many factors can cause sleep sensitivity, including some that can’t be avoided completely. However, if you’re a light sleeper, there are measures you can take to get better rest. Quality sleep is important for your well-being, so if a lack of sleep is affecting your physical or mental health, do seek guidance from a medical professional.