{"id":5454,"date":"2025-11-10T12:11:12","date_gmt":"2025-11-10T12:11:12","guid":{"rendered":"https:\/\/integrativa.pt\/?p=5454"},"modified":"2026-01-30T23:46:46","modified_gmt":"2026-01-30T23:46:46","slug":"bad-sleep-how-the-biological-clock-and-circadian-rhythm-influence-sleep","status":"publish","type":"post","link":"https:\/\/integrativa.pt\/en\/dorme-mal-como-o-relogio-biologico-e-o-ritmo-circadiano-influenciam-o-sono\/","title":{"rendered":"Do you sleep badly? How the biological clock and circadian rhythm influence sleep"},"content":{"rendered":"
\n\t
\n\t\t
\n\t\t\t

The human body works according to an internal clock known as the circadian rhythm. This system plays a part in organising multiple biological functions, such as sleep, appetite, body temperature, hormone production, energy levels and mood.<\/p>\n

This rhythm is naturally synchronised with the cycle of light and darkness, i.e. the rising and setting of the sun. Over the course of evolution, the human body has adapted to this pattern, using light as the main warning signal and the absence of light as a rest signal.<\/p>\n

When daily habits persistently deviate from this cycle, for example by going to bed late on a regular basis, waking up to sudden stimuli, spending long periods exposed to artificial light at night or keeping very irregular hours, the body may find it more difficult to organise its internal rhythms properly.<\/p>\n

Light and darkness: regulators of the biological rhythm<\/h4>\n

During the day, exposure to natural light encourages the production of cortisol, a hormone associated with alertness, concentration and energy mobilisation. As the light diminishes towards the end of the day, the body tends to gradually increase the production of melatonin, a hormone that is essential for inducing sleep and for the processes of cell recovery and regeneration.<\/p>\n

Today's lifestyle, characterised by constant artificial lighting, prolonged use of screens and irregular schedules, can interfere with this natural transition. Exposure to bright light at night can delay the release of melatonin, making it difficult to fall asleep and jeopardising the continuity and depth of sleep.<\/p>\n

Over time, this mismatch can be reflected not only in night-time rest, but also in metabolism, hormonal balance and emotional regulation.<\/p>\n

Signs of possible circadian rhythm maladjustment<\/h4>\n

Some signs that may suggest a maladjustment of the biological rhythm include:<\/p>\n