Not being able to sleep – particularly in its most severe form, insomnia – can not only be frustrating and boring at 3am on a Tuesday, but will have a knock-on effect on you the following day, and can have serious long-term ramifications for your overall health.

But why are you struggling to catch some zeds? Often it’s stress or overthinking, we thought it’d make sense to investigate what keeps you up at night – and what you can do about it.

1. There’s a full moon

No, this doesn’t make you a werewolf, and there’s no need to howl, but according to scientists, many of us lose around 20 minutes of sleep when there’s a full moon. That might be because more moonlight it is sneaking through the curtains, but there are some indications that internal circadian rhythms are linked to the lunar cycles.

[Related story: What missing out on your beauty sleep really does to your skin]

2. Dust mites

You might hate sharing your bed with your partner, but even if you take them out of the equation, your bed is probably still teeming with unwanted visitors. It turns out that 29% of Brits suffer from dust mite allergies, and yet 57% of us don’t actively protect ourselves from them, when all we need to do to make a difference is wash your bedsheets at 60 degrees and change them once a week. You’ll significantly cut the risk of allergy flare-ups and can rest easy knowing your bed isn’t crawling with microscopic bugs.

3. Get the temperature right

Are you a socks on or off kind of sleeper? Your body will have an optimum level for sleeping, so even if the heating is whacked up and it’s minus 5 outside, you might need to open the window just a sliver, or put on another jumper. Listen to your body.

4. Blame your toothpaste

A UK study found that the smell of peppermint can make people feel less drowsy, so it might be an idea to brush your teeth a bit earlier than right before you hop into bed, or try a not-so-minty toothpaste.

5. Watch a mellow bedtime TV show

We all know that emails and Twitter before bed are a big no-no, but it’s been suggested that, if you really can’t forego TV in the evening, ditching thrillers and action adventures in favour of light comedies before going to sleep will also help stop your mind from racing, making it easier to doze off.

[Related story: 10 ways to stop snoring – and get a good night’s sleep]

6. Take your vitamins in the morning, not at night

Good on you for remembering to take your vitamins, but if your supplement is packed with vitamin B12, take it when you wake up in the morning instead – it’s an energy booster, which is not what you want when you’re trying to nod off.

7. You’re exhausted

Being exhausted is not the same as being tired. When in the former state, your body may be out of energy, but your mind can still be working overtime. Try a hot bath to wind down and relax your brain and bring it back in line with your body, ready for sleep.

8. Restless legs syndrome

Also known as Willis-Ekbom disease, restless legs syndrome is, according to the NHS, “a common condition of the nervous system that causes an overwhelming irresistible urge to move the legs”. It can also cause an “unpleasant crawling or creeping sensation in the feet, calves and thighs” and is often worse at night, leading to tiredness. See your GP if you have any persistent symptoms.

9. You didn’t eat enough cheese

Everyone thinks eating cheese before bed can give you nightmares, but according to a 2005 study by the British Cheese Board, cheese can actually give you pleasant dreams. So if nightmares often wake you up, snack on a bit of cheddar before dozing off – you might just sleep right through them!

What keeps you up at night? Tell us in the Comments section below.