We all know how much sleep we're recommended to have per night, but sometimes getting eight hours a night isn't enough to leave us feeling refreshed and ready for the day.
So how do you know when you've gotten enough rest, and how can you improve your sleep quality?
Andrew Coogan, a behavioural neuroscientist and Director of the Chronobiology and Sleep Research Laboratory at Maynooth University, joined Today with Claire Byrne to discuss getting the most optimal sleep and how much is really enough.
On that eight-hour rule, he says it's not quite that simple. "Adults from about 25 to 65 are recommended to get between seven and nine hours sleep", he says. "That reflects that we are different. Sleep is an individual trait so what works for me mightn't necessarily be what's optimal for you."
The guidelines, he adds, suggest an hour on either end of that scale is actually okay.
"We want people to be mindful of their sleep and to prioritise their sleep health, because we know there's lot of benefits of that, but we're mindful as well that we don't want people to become anxious" about it, he says.
While six or seven hours might be just enough for some people, others struggle if they miss just one night of a full eight-hours sleep, which can lead to the idea of "catching up on sleep" at the weekend or on days off.
Coogan says this idea that we "accumulate a sleep debt" is a hot topic in sleep science. Does catching up on sleep when we can help avoid negative side effects from lack of sleep? "The evidence is sort of up-in-the-air a little", he says.
"If you can get sufficient sleep during the working week, do. That's better than trying to catch up. If you can catch up, that is probably better than trying to not catch up and keep to the same schedule."
The health implications of not getting enough sleep are serious, he says. "The night is actually the part where our biology is telling us, guys, we should be asleep. So our concentration, our cognition, they're all at the lowest levels. Our body temperature is at its lowest level."
Coogan says this is especially concerning for late night shift workers or workers who stay up and work for long hours. "We know that can be associated with a higher level of workplace accidents", he says, as well as work productivity.
Melatonin has become one of the more popular sleep aids on the market, but can you take it every night? Coogan says it's available through prescription and only in a certain formulation, so it should be taken under medical supervision.
"Melatonin can be very powerful. It's not a panacea", he adds. He says if you're using it as a supplement, it would be better to talk to your GP and get it properly formulated and monitored.
