Overtiredness in newborns during the summer season: circadian dysregulation and parental prevention strategies

Overtiredness in newborns, understood as a state of neurophysiological overfatigue resulting from prolonged wakefulness or fragmented and qualitatively inadequate sleep, takes on a peculiar relevance during the summer season. During this period, environmental factors such as high temperatures, prolongation of the photoperiod and alterations in daily routines interfere with the delicate regulatory mechanisms of the sleep–wake rhythm.
In newborns, in fact, sleep organization is still immature and strongly depends on the interaction between homeostatic regulation and progressively maturing circadian signals.

Sleep physiology in the newborn

Neonatal sleep is organized into short cycles, lasting approximately 40–60 minutes, characterized by a predominance of active sleep (REM-like), which can represent up to 50–60% of total sleep.
Physiological wake windows are limited, generally ranging between 45 and 90 minutes in the first months of life; exceeding these intervals leads to an alteration in the neurochemical balance that regulates the sleep–wake transition.
In physiological conditions, the accumulation of adenosine during wakefulness exerts homeostatic pressure that favors falling asleep, while GABA-mediated (γ-aminobutyric acid) inhibitory systems promote sleep stability by reducing cortical neuronal activity. Parallel to this, serotonin contributes to the modulation of sleep–wake cycles and emotional regulation.

Neurophysiological mechanisms of overtiredness

When the newborn remains awake beyond their physiological capacity, a stress response mediated by the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis is activated, with an increase in cortisol and catecholamine levels (adrenaline and noradrenaline).
The resulting state of hyperarousal interferes with GABAergic circuits and the homeostatic pressure of adenosine, generating a functional paradox: despite the accumulation of tiredness, the nervous system remains in a state of activation that hinders falling asleep and promotes fragmented and shallow sleep.

Clinical manifestations of overtiredness

From a clinical point of view, a newborn in a state of overtiredness manifests signs that are often counterintuitive:

• marked irritability
• inconsolable crying
• motor hyperactivity
• feeding difficulties
• arching of the back
• resistance to falling asleep

In more prolonged cases, sleep fragmentation can interfere with growth hormone secretion, metabolic regulation and neuronal maturation processes, as well as significantly affecting the family balance.

The role of parents in prevention

In this context, parental behavior plays a decisive role in both prevention and management of the condition. It is essential that caregivers develop refined observational skills, able to catch the early signs of sleepiness, such as reduced motor activity, a less focused gaze, repetitive movements, or mild signs of irritability, intervening promptly before the newborn enters a state of neuroendocrine overstimulation.

Anticipating falling asleep relative to the appearance of late signs, such as intense crying or marked agitation, allows for preserving the effectiveness of the GABAergic mechanisms and favors a smoother transition to sleep.

Routines and circadian regulation

The structure of predictable routines takes on particular importance during the summer months, when family habits tend to become more irregular. Parents should maintain relatively constant sleep times, avoiding excessive delays in bedtime. The introduction of repetitive evening rituals, characterized by a progressive reduction of sensory stimuli, calm interactions and a low-light environment, facilitates the activation of neurobiological sleep circuits and circadian synchronization.

Management of stimuli and feeding

From a behavioral point of view, it is appropriate to limit environmental stimuli in the hours preceding sleep, avoiding excessively noisy or socially activating contexts. Even during trips or vacation periods, maintaining moments dedicated to rest in suitable environments helps prevent sensory overload. Regular and adequate feeding, possibly more frequent on hot days, further supports behavioral stability and reduces overlapping factors of irritability.

Overtiredness in the newborn during the summer season is therefore the result of a complex interaction between the immaturity of the neuroregulatory systems, including the GABAergic, serotonergic circuits and mechanisms mediated by adenosine, and environmental factors that disrupt their balance. A conscious parental approach, based on the regulation of the environment, the predictability of routines, and careful reading of the child’s signals, allows for significantly reducing the incidence of this condition, promoting more stable sleep and more harmonious neurophysiological development.