If you already have a sleep debt going into your trip, then you could be irritable and fatigued, which isn’t exactly ideal on vacation. (And when you’re in the sun, your body works harder to maintain its core body temperature, which is a process that can leave you feeling pretty exhausted. Being in a sleep debt can add to your sun fatigue.)
Although sleep needs are individual-specific, people 18 to 64 generally function their best after sleeping between seven and nine hours per night, according to research published in March 2015 in Sleep Health: Journal of the National Sleep Foundation.
2. Drink plenty of cool water to avoid becoming dehydrated.
If you’re at the beach on a warm day, then there’s a good chance you’ll get pretty sweaty. This is helpful for keeping yourself cool, but sweating can also lead to dehydration and make you fatigued.
Source : https://www.glamour.co.za/wellness/6-beach-tips-that-can-make-your-trip-less-exhausting-85421f08-8bf2-428e-a794-28064297e7c7155