Circadian rhythm
We do not ski always the same way. Skiing is exteriorized with constant changes due to environmental conditions but also to our own regular variations, passing through particular periods or cycles indicating that our skiing is not always constant. This is in part due to our biological clock but also to internal (mood states) and external factors (weather changes, lunar phases). The most common cycle affecting us is the circadian rhythm. Circadian comes from circa (around) and diem (day) and it is defined as our internal clock that regulates behavior and body functioning variations occurring in a 24 hours’ period.
Many biological functions increase and decrease in cycles that recur during the day, the month, and the year. These reflect daily cycles of light and dim as also our organism’s biological rhythms generated by this internal clock. These rhythms affect our behavior and skiing performance like mood, memory, and alert time. They mark day cycles in which we are more or less alert, active or tired, influencing our physiological functioning in terms of time to sleep, eat or activities, affecting learning and skiing performance. These rhythms are applied to body temperature, sugar in blood, sleep-wake state, heart pace, and hormone regulation.
According to the functioning of the mentioned rhythms, our circadian rhythm determines the difference between preferring skiing in the morning or during the afternoon. These preferences influence our mental and physical performance. Scientific evidence has determined certain generalities, such as sports performance, increases if we respect our own rhythm.
Restful sleep
After a day’s skiing, appropriate sleep is essential to restore our organism. Sleep patterns are regulated by two processes: the simple physical needs and the circadian rhythms. Today is known, proven by neuroscientific studies, that sleeping seven to eight hours each night is vital to our physical and mental health, to consolidate our memories and what we have learned. On the contrary, the lack of sleep or sleep poorly not only upsets our body impairing cognitive functions and difficulty concentrating, but it also alters our mood.
The sunset activates melatonin, which is the main regulatory hormone of the sleep-wake cycle, using the uptake of reduced external light by certain ocular photoreceptors. If melatonin production decreases by reducing sleeping hours, in addition to producing a homeostasis imbalance (our normal body functioning), it affects, among other things, our memory and the ability to learn because of the lack of motivation and the feeling of low energy. At dawn, according to each person’s internal clock, the brain releases dopamine (an excitatory neurotransmitter) generating the necessary energy for the start of a new day.
During sleep, our brain reorganizes and repairs itself. Among other processes, the hypothalamus is activated in some phases and the thalamus (sensory regulator) activity decreases so that it can process the received information. During REM sleep (Rapid Eye Movements) phases, our brain and body recharge energy. These phases, that are repeated several times, are key for our memory storage and the consolidation of what has been learned during the day. Dreams occur during these phases and it is presumed that while dreaming, our brain assimilates what was experienced during the day.
Circadian synchronization and de-synchronization
The circadian system consists of three components: the synchronizer component (the sun), the oscillator component or biological clock (inside the body), and the exogenous rhythmic component (outside the body).
Because of genetic propensities, we do not have the same biological rhythms. There are morning people called larks, which are active during the day, e.g., older people, and evening people called owls, which find it difficult to wake up but are more active by evening as the teenagers.
A delay in the system occurs when our biological clock is one hour but for the world, it is another. For instance, jet lag is a delay occurring by crossing time zones by plane (trans-meridian flight).
