How sound-based alarm clocks affect sleep

If you’ve ever felt groggy, weak, unable to concentrate and generally “a little off” after waking up, it might just be time to consider how you wake up.

Most people will use a sound-based alarm to shock themselves out of sleep. This solution has been employed for hundreds, if not thousands of years to bring ourselves into wakefulness.

In isolated cases, this has led to reactions like seizures and irregular heartbeat but, for most of us, the reaction is not that extreme.

Whether you’re an early bird, night owl, shift worker or anything in between and want to be at your best throughout the day, it’s best to train yourself not to use any sort of alarm at all (a hard task, and very likely to result in you waking up later than you’d like to begin with). The second best option is to use a light-based alarm clock.

Let’s take a look at the science behind why light based alarms are so effective.

Not all sleep is the same

Sleep has a number of stages to it, each with their own distinct function and features, e.g. amount of body and eye movement, breathing rate as well as the ease from which you can wake from them.

The first stage of non-REM sleep (N1) is the easiest to wake from and N3 is the most difficult. Now, a good alarm clock will wake you up regardless of what stage of sleep you might be in so that you can go about your day, and loud noises are a sufficiently alarming(!) way to rouse a person from any stage of sleep. This is why noise is the waking device of choice used in most alarm clocks.

However, there is a problem with not taking account of the stage of sleep you’re in prior to waking and instead waking at a specific time; this is due to something called sleep inertia.

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The basics of sleep inertia

Sleep inertia is a state of reduced mental and physical performance that occurs after waking and is characterised by:

  • poor decision making
  • bad mood
  • feelings of disorientation and confusion and
  • muscle weakness.

Typically, these effects only last a few minutes into waking but have been reported to persist for as long as four hours.

In some cases, the symptoms of sleep inertia are similar to those of spending the previous night awake- it’s like being sleep deprived after sleeping!

Multiple factors influence the severity of sleep inertia, but the most critical is the stage of sleep that you wake from; the deeper the stage of sleep that has been interrupted, the worse the resulting sleep inertia will be.

For example, if you were to wake from N3 (deep sleep), you would have more severe sleep inertia than someone woken from N1 (light sleep).

Because we don’t know what stage of sleep we’ll be in when a traditional alarm clock sounds and that the severity of sleep inertia on waking depends on the stage of sleep we wake up from, we can’t know just how bad an episode of sleep inertia will be from day to day.

Many people are sleep deprived due to their sleep cycle conflicting with their daily schedule because of factors like:

  • going to bed late and having to wake up early
  • working shifts
  • being in a job that requires them to be awake for long periods

Because of these factors, it is likely that these people will spend more of their time asleep in a deeper stage of sleep.

This means that when their alarm does sound and they wake up, their symptoms of sleep inertia will be severe. This leads to an awful start to the day on top of a worsening of existing sleep deprivation.

So it’s only reasonable to ask “surely there must be a better way to wake up?” Indeed there is, a light-based alarm clock, or dawn simulating light.

The light-based alarm clock

A light-based alarm clock is a more natural alternative to a sound-based alarm clock.

This is because the human body is remarkably sensitive to light and dark; it cues the release of hormones associated with wakefulness in bright environments, and sleepiness in dark environments.

Light-based alarm clocks typically work by raising the intensity of the light they emit shortly before your desired waking time, so as to mimic the effect of a rising sun, giving a more gradual “waking up” process that is more in tune with your sleep cycle. This is important for a few reasons:

  • The effects of sleep inertia are reduced when using a light-based alarm, partly because the light is less likely to wake you during deep sleep, meaning you feel fresher at the start of the day.
  • Studies suggest your mood on waking will be improved when using a light-based alarm clock to wake up.
  • You’re more likely to experience cognitive benefits such as improved memory and concentration when you wake up in response to light rather than sound.
  • The more natural, gradual waking process of a light-based alarm clock may reduce the likelihood of a “post-lunch dip,” where you feel sleepy in the afternoon.

The benefits don’t stop there

Because light exposure regulates the cycle of hormones associated with feeling sleepy and awake, sleep deprived populations might benefit from the use of a light-based alarm clock as part of a program to establish a more regular sleep pattern.

Why not a mobile phone?

Advances in mobile technology have been rapid over recent years with smartphones replacing dedicated sat nav devices, mp3 players, cameras and yes, the alarm clock.

Although many sophisticated apps exist, which take into account your sleep phase and can wake you with either sound or light, there are two main problems with them:

  • A mobile phone display simply isn’t bright enough to simulate a rising sun and generate the necessary hormonal response.
  • Most mobile phone apps require the mobile phone to be close to you while you’re in bed to work. With that comes the temptation to use it before going to sleep. This leads to poorer quality sleep because of the type of light that most mobile phone displays emit.

Given the importance of good quality sleep to overall health, it’s well worth considering replacing your sound-based alarm clock and getting a light-based solution so you can start experiencing their many benefits.

What’s next?

If you don’t already own a light-based alarm clock, we recommend you get one. The downside is that they can be expensive. Prices start around £25, with top-end solutions costing up to £140. However, we feel that it’s an investment worth making as a light-based alarm clock will likely improve your mood and productivity for years to come. So, for most people, they are a sound investment.

You can find a huge variety of light-based alarm clocks on Amazon.

All the ones we have experience with are straightforward to set up. You can also think about investing in thick curtains or blackout blinds to control your light exposure completely.

In short:

  • Sound-based alarm clocks shock you into waking up.
  • When we wake up in this way, we can experience sleep inertia - feeling groggy, strange and not at our best.
  • Waking up using light instead can cause us to feel more alert, can enhance mood and lead to better memory and concentration throughout the day.

Controlling light to help you wake ‘naturally’ can make a large difference to how fresh you feel when you wake up and increases the chances that you can get into a routine and improve your sleep. Unfortunately it won’t fix everyone’s sleep problem.

Depending on the severity of your sleep issues you might need more help. Sleepstation offers online CBTi therapy which has been clinically proven to be the most effective method of treating all forms of insomnia. You can find out if Sleepstation could help you sleep better by completing a short questionnaire.