Health Check: why swimming in the sea is good for you

From theconversation.com

If you live near the sea, make frequent trips to the beach, or are planning an island holiday this summer, chances are you’re getting more out of it than just enjoyment. It has long been thought sea frolicking has many health benefits.
Historically, doctors would recommend their patients go to the seaside to improve various ills. They would actually issue prescriptions detailing exactly how long, how often and under what conditions their patients were to be in the water.
Using seawater for medical purposes even has a name: thalassotherapy.
In 1769, a popular British doctor Richard Russell published a dissertation arguing for using seawater in “diseases of the glands”, in which he included scurvy, jaundice, leprosy and glandular consumption, which was the name for glandular fever at the time. He advocated drinking seawater as well as swimming in it.
To this day, healing and spa resorts by the seaside abound. They are thought of as places where people can not only let go of their troubles but, in some cases, even cure arthritis.
But does the evidence actually stack up? Does seawater cure skin conditions and improve mental health symptoms?

Skin conditions and wounds

Ocean water differs from river water in that it has significantly higher amounts of minerals, including sodium, chloride, sulphate, magnesium and calcium. This is why it’s highly useful for skin conditions such as psoriasis.
Psoriasis is a chronic, autoimmune (where the immune system attacks healthy cells) skin condition. People with psoriasis suffer often debilitating skin rashes made of itchy, scaly plaques.
Bathing in natural mineral-rich water, including in mineral springs, is called balneotherapy and has long been used to treat psoriasis. There is also evidence for climatotherapy (where a patient is relocated to a specific location for treatment) in the Dead Sea being an effective remedy for the condition.
Patients suffering from psoriasis have themselves reported feeling better after swimming in the ocean, but this may also have to do with sun exposure, which has been found to improve psoriasis symptoms.
Ocean swimming also has benefits for eczema, another immune-mediated condition. Swimming in the sea can be a good exercise option for those with severe eczema as they often struggle to exercise in the heat and chlorinated pools.
But the response of eczema sufferers to saltwater is variable: some find it soothing, others uncomfortable.
There is some evidence to support the idea magnesium absorption is beneficial for the skin of eczema sufferers – presumably because it makes it less dry – as those using Epsom salt baths will attest. This may happen because magnesium-rich seawater may improve moisture retention in the skin, making it stronger and more rigid.
Because it is rich in other mineral salts such as sodium and iodine, ocean water can be considered an antiseptic, meaning it may have wound-healing properties. On the other hand, swimming in the ocean with open wounds may expose you to potential bacterial infections.

http://theconversation.com/health-check-why-swimming-in-the-sea-is-good-for-you-68583