Why? You may have a syndrome of "phase delay", a small disruption of the internal clock which delays the time to fall asleep and awake, or you accumulate your knowledge mistakes that send a signal waking brain, making, for example, sports or night by slipping into a warm bath. The catch? This raises the core body temperature. Now this is one of the awakening of the metabolic components. Another thing not to do: read an e-book or watch a movie on shelf. The LEDs of these screens emit blue light that disrupts the secretion of melatonin, the sleep hormone. And the decline may reach 22% after 2 hours. In any case, "exposure to light in the late afternoon arrival delays sleep," insists Professor Damien Léger president of the National Institute of Sleep and Alertness and author of "Sleep well, finally! "(ed. First).

Goal: Resynchronize my biological clock and / or learn to feel the sleep signals.

Good conduct:   The prelude to sleep phase lasts 10 minutes, look for signs (slight numbness, vigilance drop ...) or take a cool shower to trigger it. Therefore, lie down illico (brush your teeth upstream ditto to prepare the breakfast table) risk pushing the first cycle to the next, ie 90 minutes later. Adept evenings reading? Come back to paper books. Dim the lights, do not do sports after 19h and 16h after zap cola, tea, coffee -Attention, filter coffee contains three times more caffeine than espresso, because it is the contact time between the water and coffee which defines its concentration-, alcohol. Enjoy a sedative infusion: chamomile, verbena, hawthorn flowers, passionflower (In herbalism).

And also : Complete with light therapy. One device can act on sleep onset and awakening in the morning, "the evening he played the red-orange light that is found in the rooms sleep centers, as it facilitates the secretion of melatonin and and promotes sleep, "explains Prof. Light. And at dawn, it delivers a bluish light that stops the secretion of melatonin and boosts the release of cortisol, which stimulates alertness. But advanced equipment (Zyken NightCov, 1180 €) has a price ... The standard units (from 150 to 250 €) are used to wake: they issue a "daylight" powerful -from 1000 to 1500 Lux allowing advance gradually the internal clock involved in the phase delay.