Exhausted After the Beach?

Ever wonder why you feel exhausted or just outright pass out, after hitting the beach or just being out in the sun? Is it just you getting older or something else?

We've all had the experience of struggling to stay awake after a sudden rush of sun exposure in the summer. My kids seem to do it no problem, day after day but I'm ready to just pass out and never wake up. What's going on?

Internal Clock

Our biological clock uses light exposure as one of the important factors for regulating a sleep schedule. Light signals that it's time to wake up and the lack of light signals that it's bedtime. Sudden exposure to a large amount of sunlight may reset the clock, triggering sudden drowsiness once you get out of the beach.


The human body's internal temperature is quite fragile and functions properly under rather strict ranges of temperatures. If your core temperature drops (hypothermia) or rises (hyperthermia) a few degrees, you could be in serious medical trouble. The human body has mechanisms to regulate the core temperature, like shivering, and sweating, but all this physiological effort consumes energy, leaving you feeling exhausted.


Spending time out in the sun can dehydrate you due to sweating, even if you're not particularly active. Your body is losing both water and salt through sweating, leading to symptoms of mild to moderate dehydration-exhaustion and sleepiness.

Most people think of dehydration as equivalent to the sensation of thirst, but this is actually not accurate. By the time that you feel thirst, your body is significantly dehydrated. The sensation of thirst also decreases with age, so it's very important to be drinking water before you feel the thirst.

Oxidative Damage and Chemical Changes

The sun emits UV radiation which has a variety of harmful effects on people. The main rays that penetrate the ozone layer are UVA and UVB light. When these rays hit the skin, it induces a cascade of chemical reactions in the body that taxes the body. These may be contributing factors to exhaustion.

The Takeaway

Exhausted after the beach or a picnic at the park? Lots of changes are happening in your body while you are being exposed to the sun, and if you aren't used to it, the urge to pass out might be irresistible! These physiological reactions are natural so there is no cause for alarm, but make sure that your skin is well protected with broad spectrum sunscreen.