The reason why feet shouldn't be covered while sleeping is because having your feet covered all the time when sleeping can hinder blood circulation, overheating and possibly cause skin irritation or infections if the covering of the feet is too tight or is not breathable.
Leaving your feet uncovered while sleeping helps to regulate your body temperature, which is also essential for maintaining sleep and initiating sleep, because the heat from your feet needs to be able to dissipate to signal your brain that it's time for sleep.
Our human feet also have temperature sensitive skin, which plays a critical role in our body's overall temperature regulation.
And dispersing of the heat from our feet also helps our core body temperature to drop and signal that it's time for us to sleep.
Keeping your feet cool, by not covering them can also help you fall asleep faster and improve your sleep quality.
Sleeping with uncovered feet, especially in summer, allows for the evaporation of sweat, which can also prevent irritation of the skin and reduce your risk of developing bacterial infections or fungal infections.
And when your feet are covered, the covering of the feet can trap heat and result in overheating and disturb your sleep.
And if you wear socks that are too tight it can restrict blood flow to the feet and can be detrimental, especially if you have certain health conditions such as diabetes.
And covering of your feet with materials that are not very breathable or lack ventilation or covering your feet with coverings that have harsh chemicals can result in allergic reactions, infections and skin irritations.
Wearing socks to bed can also disrupt your body's natural sleep processes and some people might even become reliant on socks to sleep.
Although if your feet are old, sleeping with feet covered or socks can be a good thing.
But if you have poor blood circulation or swelling in your feet, "edema" or if you're prone to overheating or skin infections or if your socks are too tight or made of non breathable materials it's best to avoid socks when sleeping unless you're cold.