Regulating health with zeitgebers

Received from NaturaFoundation, 10 December 2017

The role of our biorhythms is greater than many people think. For instance, a good night's sleep can make a huge difference to our health and functioning. When we don't sleep well, it even disrupts the physical communication between our brain cells. High time we delved into zeitgebers.

"A life in violation of one's biological clock can pose a danger to one's health and well-being." - Prof Till Roenneberg, chronobiologist [1]

Zeitgebers are external factors that regulate our biological clock. The best-known zeitgeber is sunlight. When the sun rises, the body starts producing more cortisol and we wake up; when it gets dark in the evening, melatonin production goes up and we become sleepy. Diet, exercise and social interaction are also zeitgebers. Each of them has a strong effect on our biological clock. And along these lines, they affect our health.

What time is it actually?

Our internal clock synchronises itself with external zeitgebers. Under natural conditions, the communication between our biological clock and zeitgebers provided a rhythm of life that fitted within the natural environment.

Our biological clock has remained the same for the past ten thousand years, but our environment has changed beyond recognition. You might ask yourself how many of the above zeitgebers still indicate 'the right time'. The sun rises and sets again, but how much of it does our biological clock still get?

Most of us surround ourselves with artificial light all day. This keeps us awake at night when it gets dark outside. Many people also check their mobile phones or tablets before going to bed. The internal clock 'thinks' it is still daytime, delaying the production of melatonin.

Factors that disrupt sleep

Factors that can disrupt (or induce) sleep are often zeitgebers that did not occur in our natural environment. These might include:

• Artificial light: lamps, television, tablet, laptop
• Temperature, atmospheric pressure
• Feeding frequency, time, amount
• Certain nutrients and supplements Medicines and drugs
• Exercise deprivation, sedentary lifestyle
• Social stress

As mentioned, artificial light disrupts the communication between the natural zeitgeber (daylight) and our circadian rhythm. But the temperature around us - which is registered by the hypothalamus - also communicates with our biological clock. Around the equator, where the weather is relatively stable, the temperature varies with the position of the sun.

At the warmest part of the day, we rest; when it gets colder, activity levels increase again. Central heating provides a stable temperature, so our hypothalamus does not need to regulate our indoor temperature. So the zeitgeber that regulates this rhythm is effectively switched off.

Nutrition and supplementation as zeitgebers

In terms of nutrients, perhaps the most telling examples are caffeine and the amino acid L-tryptophan, which is converted into melatonin. The latter is often given in supplement form for jet lag and sleep disturbances with other causes.

While effective, it is not a long-term solution. If we want to restore our biorhythms - and ensure our health - it is important to look at our evolutionary background. Then we see that we need to reconnect as much as possible with the rhythms of zeitgebers within the natural environment: sunlight, outdoor air, temperature gradients, incident darkness, twice-daily eating, bulk drinking and social interaction.

Why sleep is healthy

Why do we need all that sleep anyway? Modern science is slowly starting to unravel the secret. Here is a small overview of the main functions that have been demonstrated so far.

• Processing and storage of particularly visual impressions Information processing in general
• Reorganising brain connections and storing memories Childhood brain development
• Removing waste from brain Energy production and storage in brain cells Mood, appetite and libido

Deep relaxation

The more new experiences one has and the busier one gets, the more important it is to sleep well. And that is precisely what many of your clients do not do. Rather the opposite: they stay up longer to watch that exciting film, finish work behind the laptop, or respond to phone messages that have not yet been answered in the rush.

Consequences of poor sleep

It was recently discovered that sleep deprivation has a similar effect on our brains as drunkenness [2]. Poor sleep causes the communication between brain cells and different brain areas to be impaired. In drunkenness, the activity of certain brain regions decreases one by one until they shut down completely (blackout).

In this way, poor sleep makes us less able to concentrate, depresses our mood, decreases appetite and lowers libido. We also process new information less quickly and assign it to our behavioural repertoire less energetically. But more importantly, poor sleep causes poor waste disposal in our brain. In the long run, this could possibly lead to Alzheimer's.

Marijke: If your functioning and productivity are suffering due to lack of sleep or if you face jet lag due to your work, I can help you overcome this with the right advice. Take contact with me for more information.

Sources
[1] Till Roenneberg, The inner clock (translated from the German), Babel & Vos Publishers, Amsterdam, 2012
[2] Selective neuronal lapses precede human cognitive lapses following sleep deprivation, Nature Medicine