Why Does Sunbathing Make You Tired?

Being in the sun all day and being outdoors when the sun sets just naturally makes you tired, too. It's why people who go camping feel ready for bed at 8 p.m., says Dr. Winter. “Being in the sun suppresses [the sleep hormone] melatonin, and then when the sun goes down, your body produces melatonin,” he explains.

Why do I get sleepy after being in the sun?

In addition to heat, the sun exposes you to ultraviolet (UV) rays, which can make you feel tired. ... Since UV rays damage the skin, your immune system also kicks in to try to protect you against sun exposure.

Why does being hot make you tired?

Vasodilation is the process by which your blood dilates, allowing more blood flow close to the surface of your skin, which releases heat. This allows you to cool down but also can make you appear "flushed." This takes up energy and can make a person tired. ... Excessive sweating can make you extremely tired and sleepy.