Some people say they do fine on 4 hours of sleep.
However in reality 4 hours of sleep is not enough for staying healthy and waking up well rested as well.
At minimum a person needs 6 to 8 hours of sleep to stay healthy and wake up refreshed.
And some people need 10 hours of sleep to stay healthy.
4 hours of sleep per night isn't enough to wake up feeling rested and mentally alert, no matter how well they sleep.
There's a common myth that you can adapt to chronically restricted sleep, but there's no evidence that the body functionally adapts to sleep deprivation.
Most adults need 7 to 9 hours, although some people may need as few as 6 hours or as many as 10 hours of sleep each day.
Older adults (ages 65 and older) need 7-8 hours of sleep each day.
Women in the first 3 months of pregnancy often need several more hours of sleep than usual.
Research shows not meeting your sleep need over time can lead to an increased risk of health problems, such as: Weight gain that can lead to obesity or a higher body mass index (BMI) Type 2 diabetes.
Cardiovascular diseases, like high blood pressure.
Sleep is an essential function that allows your body and mind to recharge, leaving you refreshed and alert when you wake up.
Healthy sleep also helps the body remain healthy and stave off diseases.
Without enough sleep, the brain cannot function properly.
Lack of sleep is associated with many negative health effects, including increased risk of heart disease, depression, weight gain, inflammation, and sickness.
Though individual needs vary, most research suggests that you should get between 7 and 9 hours of sleep per night for optimal health.