Why does your body feel different after a day at the beach?
You've done nothing. You lay on a towel, dipped in the water, maybe had a snack. And by 5pm you're wiped out, head thumping, skin tight.
A beach day is harder on your body than it looks, and it comes from several things stacking up at once.
Wind and sea breeze hide how much you're sweating
A sea breeze evaporates sweat almost as fast as you make it, so you never feel sweaty. Your skin feels dry, so you assume you're fine. But you're losing fluid and sodium the whole time, and you have no visual cue to tell you.
Sun takes more than it gives
New Zealand's summer UV is fierce, and sunburn draws fluid to the skin's surface and away from the rest of your body. Even without burning, hours in direct sun push up your core temperature and your heart works harder to cool you down.
Soft sand is hard work
Studies suggest walking on soft sand takes roughly twice the energy of walking on firm ground. That stroll along the beach is a proper workout.
And seawater doesn't help
Swallow a decent amount of seawater and your kidneys need more water to flush out the salt than the seawater supplied. You end up further behind.
A FEW THINGS WORTH TRYING
Plan your drinks, not just your snacks. Pack a full bottle per person and keep it in the shade so it stays cold and inviting.
Bring something salty and an electrolyte drink. You're sweating without noticing, so replacing sodium as well as water works better than water alone.
Alternate alcohol with water. Beach drinks add a dehydrating effect to an already dehydrating day.
Take shade breaks. Twenty minutes under an umbrella every hour or so lowers your heat load.
Cover up as well as slop on sunscreen. A hat and a light shirt cut the sun exposure that's draining you.
Finish the day well. A cool shower and a proper salty meal beat collapsing on the couch.
Heat exhaustion looks like dizziness, nausea, a pounding headache and heavy sweating with clammy skin. Get to shade, cool down and rehydrate. Confusion, hot dry skin or a stop in sweating is an emergency, so call 111. Blistering sunburn also needs a doctor.
A beach day feels easy because it's fun. Your body just did a lot of work.