Winter & light

We are entering the winter season. That means shorter days and less daylight. Fine if you are a wild bear and start preparing for hibernation. Well, research suggests that there were once primordial humans who also hibernated. The humanoids of the Sima de los Huesos lived between 440,000 and 455,000 years ago, in other words, during one of the most intense ice ages of the past million years.

As far as we know, no other humanoids have ever existed to hibernate. Many lived in warmer environments, where there was little incentive to do so. Bartsiokas says the primordial humans that did face harsh winters, such as the Neanderthals, were anatomically adapted to cope with the cold. This gave them their distinctive facial structures.

In the process, they may have had more high-fat animal meat available to them throughout the year. This helps present-day Arctic populations avoid vitamin D deficiencies during the dark winter months. It may be possible to achieve a hibernation-like state in living humans, says biologist Kelly Drew of the University of Alaska Fairbanks. She is investigating whether this idea could be used to treat certain conditions, including strokes or cardiac arrests.

Grass-fed meat is (high-fat) meat from cattle that eat as nature intended: grass, herbs and flowers from nature. The cattle are in pastures all year round. They do not get 'concentrate feed' which is often meant to make the animals grow faster for slaughter. Cattle are also best at digesting grass; their stomachs are made for this. As a result, they grow slower, building up more healthy fat, namely in the form of Omega-3 fatty acids. In addition, meat contains less Omega-6 fatty acids that are less good for us.

Ok, back to light. During the winter period, the sun rises later and sets earlier. And there is only around 8 hours of daylight on some days. For us Westerners, this has the consequence that we are (even) less exposed to direct daylight. And produce less vitamin D. Especially since we spend too much time indoors these days, especially in the colder period of the year.

Vitamin D is required for the absorption of calcium and phosphate from food. It therefore has an important role in several bodily processes: Growth and maintenance of strong bones and teeth. Functioning and repair of muscles. Vitamin D insufficiency can lead to muscle weakness and osteoporosis, among other things.

Circadian rhythm
A circadian rhythm is a biological rhythm whose cycle lasts about one day (Latin: approximately = round, dies = day). People also speak of a 24-hour rhythm or, in animals, a sleep-wake rhythm. Every human has a biological clock. You can think of this as an internal clock that indicates when it is time to become active and when it is time to go into "rest" mode.

When the sun sets, a number of changes take place again. During the day, adenosine accumulates in the brain and from 7pm onwards, the hormone melatonin also increases, to gradually make you sleepy. This so that you get concrete signals to go to bed.

When you are in deep sleep, a number of important hormones such as growth hormone and prolactin peak. This is for your body's recovery, but regulation of your sex hormones also takes place, for example. Your circadian rhythm is reset to start a new day.

Many living things, from bacteria to plants and animals, possess an internal regulated rhythm that allows them to anticipate regularly recurring environmental factors, such as day and night, in a timely manner. Even in complete darkness, humans and animals exhibit a circadian rhythm, controlled by an internal biological clock, which in mammals is fixed in certain brain cells.

Body temperature is a well-known example of a function with a circadian rhythm. It is highest in the late afternoon (6 hours before falling asleep), and lowest 2 hours after falling asleep. Other body functions also exhibit a circadian rhythm, such as release of certain hormones, heart rate, sleep pattern, urinary bladder volume, need for food and drink and sensitivity to certain drugs.

Routine is the key to a better circadian rhythm. You can also improve the functioning of your circadian rhythm by creating a strict sleep schedule and sticking to it. Essentially, you are training your brain to know when it is time for rest, so this will take some time. You need to choose a bedtime you can stick to every day of the week, including weekends. If you go to bed later on weekends, you will deviate from the schedule and your brain will not be able to adjust to the routine.

Restoring circadian rhythm
To restore or improve your circadian rhythm, it is especially important to manage light exposure properly. This means paying close attention to the timing, duration and intensity of your light exposure.

The diagram below can help you with that.

1. Get up at set times (including weekends).
2. • • Wake up with nature sounds and make sure the heating is on (that it is warm in the house).
     • Take a cold/warm shower.
     • Provide 30 minutes of daylight exposure (take a short walk or use light therapy).
3. Have breakfast immediately or postpone it (fasting).
4. Work or other activities.
5. Lunch (or your breakfast).
6. Stop taking caffeine or at least stop taking caffeine at least 12 hours before you go to sleep.
   Your body gets addicted to caffeine and you need it to stay energised
7. Take a short outdoor walk in between, this is good to get extra exposure to daylight.
8. Resume work or other activities (up early? you can also schedule a meal here).
9. Sports (consistently when it is most convenient, but not too late).
10. Dinner.
11. Relax or play sports.
12. Dim the lights, provide warm light, mute the noise and lower the room temperature, do something relaxing.
13. Form an evening ritual.
    • Take a hot shower in the evening 60-90 min before bed.
    • Do a short meditation or breathing exercise.
    • Take a magnesium foot bath, this helps relax your muscles.
14. Go to bed at set times. Allow for ± 15 minutes of sleep-in time.
15. Sleep in a well-darkened room.

Once your circadian rhythm is in sync with your outside environment and your sleep quality is good again? Then you no longer need an alarm clock to wake up and you can fall asleep more easily because you automatically get tired.

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Sources: newscientist.co.uk, modernative.co.uk, wikipedia.org, bell-coaching.com.