The internal clock and sleep: If it ticks correctly, you sleep better!

The influence of the internal clock: Did you know that an internal clock determines when we get tired and how refreshed we feel?

Our internal clock not only influences our sleep-wake rhythm but also our organ activity, body temperature, hormone levels, and many other processes in the body.

We all love our sleep, but how well do you know your own sleep rhythm - lark, owl or mixed type?

To put it simply, there are three sleep types, so-called chronotypes:

• Larks (early type): Their internal clock ticks faster than 24 hours, they get tired earlier and wake up earlier.
• Owls (late type): Their internal clock ticks slower than 24 hours, they get tired later and like to sleep longer.
• Mixed type: Most people are mixed types with no clear preference.

Put simply, a distinction is made between an early type, a late type and a mixed type. These three "chronotypes" describe a - largely - genetically determined temporal preference for certain sleep and wake windows in a period of time that repeats itself over and over again. But not for all people of the same length. For the early type, the period length is a little less than 24 hours: This means that the "larks" get tired a little earlier because that is how their internal clock "ticks" - in contrast to the late types, the "owls", whose period length is a little more than 24 hours [3]. They get tired later.

The transition between the types is fluid. Most people are a mixture of both without a clear sleep-wake preference. However, this also has an effect during the day: the three chronotypes differ in organ activity, body temperature, hormone levels and some other processes. [1, 2].

Society oriented towards larks

Our society is often geared towards the needs of larks. Early start times for work and school can be a challenge for owls.

Larks get tired earlier, should then go to bed and wake up earlier. Owls, on the other hand, go to bed later so they can sleep a little longer. Unfortunately, nobody cares about my sleep rhythm in everyday life, otherwise the owls would come to work later and still be sitting at their desks when the larks have already gone home. Society, with the typical start time for work and school at 8 a.m., is fundamentally geared towards early types. Late types have a disadvantage.

For owls who go to bed too late and have trouble getting going in the morning, an extra portion of daylight in the morning is recommended, for example by walking. Light and movement have an activating effect. It can also help to calm down in time in the evening and avoid activating activities. Getting up regularly at the same time is also helpful. No matter which sleep type you are: it makes sense to identify individual peak phases and use them for demanding tasks and important projects. Less demanding to-dos and routine tasks can usually be completed well even in low phases [4].

Tips to get into your rhythm:

Get to know this

• Self-observation: Pay attention to when you feel most productive and at your peak during the day. Are you a morning person or more of a night owl?
• There are RNA analyses that can help you determine your sleep chronotype.
• Experiment with routines: Test how your morning and evening routines affect your rhythm. Does exercising in the morning affect your energy? How does avoiding screens in the evening affect your sleep? Avoid activating activities in the evening and create a relaxed sleeping environment.
• Daylight: Use daylight to synchronize your internal clock.

Use your rhythm for yourself

• Make use of your peak periods: plan challenging tasks for the times when you feel fittest. Schedule routine tasks for your low periods.
• Adapt your activities to your rhythm : plan exercise, meals and, if possible, your work hours according to your peak and trough periods.
• Allow yourself breaks: If you notice that your energy is waning, treat yourself to a break or a relaxation exercise. This will allow you to recharge your batteries.
• Regularity: Go to bed and get up at the same time every day to stabilize your internal clock. Owls benefit from an extra dose of daylight in the morning to activate their bodies.

hormone replacement therapy

Hormone replacement therapy (HRT) remains one of the most effective treatments for sleep disorders, particularly when hot flushes make the problem worse. A meta-analysis shows that HRT can significantly improve sleep quality in many women, with combinations of estrogen and progesterone proving particularly effective. However, current guidelines do not recommend HRT as the sole treatment for sleep disorders. Talk to your doctor to find out if HRT is suitable for your symptoms.

Non-hormonal treatment options

There are several non-hormonal approaches to relieve sleep problems:

• Melatonin: Dietary supplements containing melatonin support your body’s natural sleep-wake rhythm.
• Valerian and hops: These herbal remedies have a relaxing effect and can gently but effectively relieve sleep disorders.
• Antidepressants (e.g. SSRIs): In some cases, antidepressants can improve mood and sleep when hormonal changes are causing problems. These require a prescription, so be sure to talk to your doctor about them.
• Blood pressure medications (e.g. clonidine): Surprisingly, medications like clonidine can help control night sweats and thereby improve sleep. These medications also require a prescription.
• GABA: GABA is a neurotransmitter that calms brain activity. As a dietary supplement, GABA can help relieve nighttime restlessness.

Did you know

...that your biorhythm is pre-programmed in your genetics?

• The Berlin startup Blockclock of the Charité has developed an RNA hair analysis that determines your individual biorhythm.
• In the Netherlands, medication intake, especially for cancer therapies, is already being adapted to the circadian rhythm. The Hamburg startup Timeteller (also a Charité Berlin spin-off) offers such an analysis.

...that your period length is influenced by a circadian rhythm?

A circadian rhythm is characterized by the period length of the internal clock, which determines the time interval until a process is repeated. This period length is genetically determined and is approximately 24 hours in the human sleep-wake rhythm.

Further information : Revealing sleep secrets on app.hermaid.me

• Our course provides you with comprehensive information on the topic of sleep and supports you in developing healthier routines and better understanding your sleep patterns. We explore different methods, from smart technology and RNA tests to determine your chronotype to simple recording with pen and paper
• If you would like to delve deeper into the subject, our expert Christine Lenz is available for one-on-one discussions. With over 10 years of experience in sleep laboratories, she will accompany you comprehensively on your way to better sleep.
• More articles on this topic: Sleep problems and solutions

Sources:

1. Merrow, M., Spoelstra, K., and Roenneberg, T. (2005). The circadian cycle: daily rhythms from behavior to genes. EMBO reports, 6(10), 930-935.
2. Cajochen, C., Chellappa, S., and Schmidt, C. (2010). What keeps us awake? The role of clocks and hourglasses, light, and melatonin. Int Rev Neurobiol, 93, 57-90.
3. Roenneberg, T. (2012). What is chronotype? Sleep and Biological Rhythms, 10, 75-76.
4. Xu Q et al. Examining the relationship between subjective sleep disturbance and menopause: a systematic review and meta-analysis. Menopause. 2014 Dec;21(12):1301-18. doi: 10.1097/GME.0000000000000240
5. Roenneberg, T., Wirz-Justice, A., and Merrow, M. (2003). Life between clocks: daily temporal patterns of human chronotypes. Journal of Biological Rhythms, 18(1), 80-90.
6. Schaedel Z et al. Management of sleep disorders in the menopausal transition. Post Reprod Health. 2021 Dec;27(4):209-214. doi: 10.1177/20533691211039151.