What happens to your eyes when you’re tired?

08 July 2021

Author: Kate Green

sleep hormones

Why do your eyes feel heavy when tired?


We’ve all been there when it gets past our bedtime – that heavy-lidded feeling that tells us the land of nod beckons. Even if you don’t feel particularly tired in yourself, the feeling of your eyes wanting to close can be quite powerful once you’ve been up and out all day. We’re going to look into the effects of tiredness on your eyes and discuss exactly what it is that causes that sleepy feeling which we’re all too familiar with.


What is the sleep hormone?


You may have heard of melatonin, more widely known as the sleep hormone. This is a hormone your body releases in the evening which keeps your circadian rhythm consistent. Your circadian rhythm is an internal process to help you stay in a regular sleep-wake cycle, thereby promoting a stable routine and sleep pattern. Melatonin helps you to feel tired in the evening and the darker your surroundings are, the more its production increases. If you spend time in light environments, be that during the day or on lighter summer evenings, production of melatonin slows down. This is why you likely find yourself feeling more tired earlier in the evening during winter, when the daylight hours are short and we find ourselves in darkness from 5pm onward.


Some people who have trouble getting to sleep may find that their body doesn’t produce enough melatonin to help them feeling sleepy in the evenings. Melatonin drops your body’s core temperature, as well as lowering your heart rate and blood pressure, preparing your body for sleep. Melatonin is usually released into the bloodstream but, in some countries, it can be sold as a supplement in the form of a pill. Research shows that melatonin supplements can help improve sleep for some people, but it’s not a long-term fix for insomnia. Although it might help you fall asleep more quickly, or help you get back into a regular sleeping pattern, you should seek advice from your doctor for long-term solutions.


Muscle tiredness of the eyes


It’s important to remember that your eyelids are more than just skin covering your eyes – they are muscles which work throughout the day to keep your eyes lubricated. Just like every other muscle in your body that you use all day, they grow tired after a few hours. If you’re sitting down, your leg muscles get a break but your eyelids are active from the moment you wake until the moment you go to sleep.


You also focus your eyes regularly throughout the day, squint against bright lights, and open them wider in darker environments. It’s no wonder that your eyes feel fatigued by the end of the day! People with excess eyelid skin may also find that their eyelids feel heavier when they’re tired, as well as individuals who have puffy eyes due to allergies, thereby finding it harder to keep their eyes open.


Why do you rub your eyes when tired?


It’s a reflexive reaction to rub your eyes when you feel sleepy, but did you know that it actually has a biological purpose too? Your eyes might feel dry if they’re tired and you can help relieve some of this dryness by rubbing them. The action stimulates your lacrimal glands in the eye, encouraging them to produce more tear fluid and hydrate and lubricate the eye better. This can alleviate some of the discomfort that comes with tired, heavy eyelids.


Ultimately, the best fix for keeping tired eyes at bay is to get your 8 hours of beauty sleep each night, and wake up for each day with refreshed, rested eyes.

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