Late nights don’t just hurt your physical health—they impact your mood, stress, and brain function too. Dr. Sethi explains, “Poor sleep timing can reduce serotonin levels,” the chemical that helps regulate emotions. People who stay up late often report feeling anxious, irritable, or sad. Over time, this may lead to depression or anxiety.
Cortisol, the stress hormone, also stays high when you sleep late. This can make it harder to relax and sleep deeply. “Your body is stuck in a state of tension,” Dr. Sethi says, which affects heart health, immunity, and energy.
Cognitive decline is another concern. “People who stay up too late often complain about brain fog and poor memory,” says Dr. Sethi. Missing early sleep stages affects how your brain stores information and processes thoughts.
To feel your best, aim to sleep between 9:30 and 11:00 PM. “Small changes in sleep timing can lead to big improvements in how you feel each day.”
