Let’s start with the most important aspect of our advice for better sleep: total darkness in the bedroom. There shouldn’t be any electrical devices with luminous dials: no alarm-clock, no mobile phone, no computer, no TV, no radio-alarm… In any case, all electronic equipment should be banned from the bedroom because they stimulate the brain and prevent you from falling asleep: there is nothing better than reading to fall asleep! Let’s forget about all the screens!
But let’s get back to darkness in detail: no luminous ray under the door or light coming through the border of the curtains which must totally block external light (not only daylight but also streetlights and other outdoor light sources, even the moon!). The opacity of the curtains can only be achieved if they are lined with a black-out material (from top to bottom) and wide (so they can generously overlap across the middle where required).
Then we need to concern ourselves with the temperature of the bedroom: here the golden rule is to be neither hot nor cold. One needs to select a temperature that makes them comfortable, whilst of course taking into account a partner’s wishes. Typically, a range of 15 to 18C is most often suitable, on the basis that it is generally better to choose a cooler temperature. The ability to reach and maintain this goal can become complicated due to climatic variations and the means of regulating room temperature at your disposal…
There is a third issue which is often the most difficult one to solve; noise. There are simple technical means to reduce noise, for example by double glazing and using seals around the doors and windows. One also needs to be vigilant about airing the room, which is compulsory, but not necessarily during the night or not in its totality. One should air the room regularly, as long as the silence is not affected during the night, closing the window before traffic starts.
It is important not to be obsessed with uninterrupted sleep: what is important is to go back to sleep quickly following a brief awakening. As for the length of sleep, we can find significant variations: 6 to 9 hours in adults, with a clear preference for 7.5 hours. We should factor in to this calculation too the length of time it takes to fall asleep and the duration of awakenings (but only if they are of significant length, i.e. more than 5 minutes).
You will notice that a normal sleep cycle is made up of multiples of 90 minutes which corresponds to the initial phase of sleep (deep sleep) and its final period of REM sleep (dreams). We typically sleep 4-6 cycles, exceptionally 7 for big sleepers (this is very often due to a pathology such as hypothyroidism). When external factors – such as an addiction to screens (TV, computer, game consoles) late in the evening – limit sleeping time to 4 cycles, most people will show fatigue after two or three days. One should then quickly work towards a night with 5 cycles to really round-up the working week before the salvation of a weekend with its 5-6 cycles.
Despite what some people may say, nobody can really survive on 3 cycles, expect for a rare occasion of course, even if adrenaline can effectively mask the real state of exhaustion. There will always be a qualitative loss of function both at the cognitive level, and also at the fine motor level. The Spanish system, which consists of ensuring 4 cycles during the working week, persists because of the splendid nap in the early afternoon. But any nap taken after 4.30pm is poorly timed and will ruin your capacity to fall asleep later.