Melatonin
This key hormone is secreted by the pineal gland when specialized photoreceptors in the eye detect the decline in external light. Apart from relaxing us, it has antioxidant and anti-inflammatory effects and can lengthen our lives, as Darío Acuña, professor of Physiology at the University of Granada, has shown.
Growth hormone
Synthesized mainly during the deepest phase of sleep, it allows you to maintain the muscle mass and strength required for physical exercises, in addition to reducing the amount of body fat. Of course, it is essential in the childhood growth stage, but if it is scarce when we are adults we will have a greater risk of suffering from hypercholesterolemia, osteoporosis, premature aging and even cancer.
Cortisol
You get up, get dressed, make breakfast, run to work, get caught in traffic, eat in a hurry to get work done, stop by the supermarket before heading home … While all this is happening, cortisol levels –The stress hormone– stay high and suppress your immune response. That is why it is necessary to wait until nightfall so that our defenses fight at ease against infections. We also need cortisol levels to drop if we want to deal with allergies effectively.
BDNF
The production of brain-derived neurotrophic factor (BDNF), which protects the auditory nerve, reaches its lowest levels when night falls. A recent investigation revealed that the cochlea or organ of hearing is more sensitive to noise at night ; it is so extreme that harmless sound levels during the day can cause irreversible hearing loss at dawn.
Connection-43
Why don’t we usually get up to go to the bathroom at night? It seems like a simple question, but the truth is that a few years ago Osamu Ogawa and his team at Kyoto University came up with the answer. The key is that our circadian clock then orders an increase in the production of the protein connexin-43 in the muscle cells of the bladder, which can thus last longer.
Orexina
When the sun goes down, the hypothalamus reduces the production of this protein, linked to the feeling of hunger. A study published in the journal Cell revealed that when this mechanism deteriorates, we lose the ability to know if we are satiated, which explains the constant nocturnal walks to the refrigerator of those affected.
