Most people will have noticed that when they are tired, their eyelids will start to droop and it can take a fair amount of concentration to ensure that eyes are kept open. This can be difficult after a long day; even more so if there has been a period of late nights, early mornings and busy days. It can seem as though the eyelids have become puffy with tiredness, increase in weight and are therefore that much more difficult to keep open. However, the reason for heavy eyelids is far simpler than some people will expect.
According to Scientific American, when any part of the body becomes tired, the muscles begin to feel fatigued. Imagine your bicep muscles after you have done a weight training session. You need to give them some time to rest and recuperate before you can do anything else with them. Your eyelid muscles are exactly the same. After a day of reading, watching, recognizing, judging distances and whatever else you use your vision for, your eyelids begin to protest about being forced to keep your eyes open and so start to tell you that you need to rest by feeling heavy.
As Mark A. W. Andrews, professor of physiology at Seton Hill University in Greensburg, Pennsylvania explains in an NBC article, your eyelids will react in the same way even if they have not been specifically overwrought during the course of the day, but your body as a whole is exhausted. He goes on to say that the problem is exacerbated when the lighting is not good: “It’s even worse when you’re working in a darker environment. Just like an f-stop on a camera (which regulates exposure), you have to make sure your eyes are fully widened, letting all the possible light in.”
The fact that the muscles have become over-fatigued also explains why your eyes can look puffy and feel heavy when you are tired. The blood flow to the eye area increases because of over-exertion and the extra pressure expands it. Some relief can be felt after an eye massage, which is good for general eye health anyway. As this website suggests, using the heel of the hand and pressing it against the eye area can be very therapeutic. For puffy eyes in particular, hot and cold flannels pressed against closed eyes can be very soothing, especially when accompanied by a massage through the flannel. There are also a number of pharmaceutical products available to ease tired eyes.
On rare occasions, heavy eyelids can be caused by an underlying medical condition; this could include a sinus infection, allergy, and any disease or intervention that affects your facial muscles. Ultimately, however, if you are constantly experiencing heavy eyelids, the chances are you won’t be able to do anything about them until you have caught up on some sleep and changed your lifestyle.