Swimming in open water

Open water swimming or wild swimming is becoming more popular.

Reservoirs, lakes, rivers and other inland water may look safe and inviting, particularly on a warm day.

But there are hidden dangers below the surface that could make you ill, hurt you, and at worst could kill you.

Open water swimming clubs

If you would like to go open water or wild swimming there are a number of clubs that offer supervised sessions. To find out more or to locate a club near to you visit:

Be aware of the dangers

Cold water shock

Even on a warm day, the temperature of a body of open water can remain very cold.

When you jump into a body of water you experience a cold-shock response. This is what happens:

  • You gasp for air. Meaning that you could breathe in water.
  • You hyperventilate. This over-breathing can make you light-headed and, as your brain is deprived of oxygen, you may become disoriented.
  • Your body’s Cold Shock Response, which speeds up the heart rate, may conflict with the Diving Response, which does the opposite, causing your heart to go into abnormal rhythms which can cause sudden death.
  • Your muscles will become weaker. Your muscle ability can drop by as much as 25%. So you may not be able to keep yourself afloat or pull yourself out.
  • Your body will shiver, which will affect your coordination and your swimming ability.

There may be hidden currents

Moving water, such as rivers, may look calm but may have strong currents below the surface. Even reservoirs can have currents, caused by working machinery.

Whether you’re a strong swimmer or not, currents can carry you into danger:

  • Trapping you against underwater obstructions or in weeds.
  • Pulling you away from where you can get out of the water.
  • Dragging you further than you’re able to swim back from.

What lies beneath?

From out of the water, or above the water, you may not be able to see what’s under the water.

  • There could be anything from large rocks to machinery; from shopping trolleys to dead branches, and even fish hooks or broken fishing line, all of which could injure you.
  • If you dive or jump into open water you don’t know what is underneath and a broken neck from a diving accident could paralyse you for life

There are no lifeguards

  • If you are thinking of swimming in rivers, lakes, canals or isolated pools remember that there are no trained lifeguards to rescue your and help you out of difficulty. You are on your own.

It can be difficult to get out

  • Banks can be steep and slimy. You may not be able to get a grip hold to enable you to pull yourself out of the water.
  • Rocks are very slippery when wet:
    • Slipping on the rocks is of the most common dangers in outdoor swimming.
    • Slipping and falling in this environment has been known to result in severe head injuries.
    • Never run or go barefoot. To get a better grip or wear plimsolls with a rubber sole.

It is difficult to estimate depth and it can suddenly deepen

  • Shallow water can deepen suddenly.
  • If you, your children or your friends cannot swim make sure you scout out the extent of the shallows, set clear boundaries and keep constant supervision.
  • Even shallow sections of fast-flowing water can knock you off your feet.
  • Buy a good quality buoyancy aid for non-swimmers and, best of all, learn to swim.
  • Be careful with inflatable’s, which can create a false sense of security and float off into deep sections or burst.

You could experience swimming cramps

  • Swimming cramp can occur in the calf or foot and tends to be caused by overexertion, over-stretching and tiredness.
  • Cramp is not more likely after eating, but dehydration or a poor diet in general can make you especially prone.
  • If you get a leg cramp, shout for help, lie on your back and paddle back to shore with your arms.

It may be polluted and may make you ill

Open water can be polluted. Things that might make you ill include:

  • Rat urine - this can cause an illness called Weil’s Disease. Weil’s disease can initially cause flu-like symptoms between 7 and 26 days after you swim and, if untreated, the secondary stage can cause death.
  • Cryptosporidium -is a parasite that gives you bad stomach cramps and diarrhoea (the runs!).
  • Trachoma -is an eye infection that can lead to blindness.
  • Whipworm - are worm eggs that hatch inside the body after being swallowed.
  • Toxic algae - can cause skin rashes and stomach upsets.

If you spot someone in trouble

  • Call 999 immediately
  • Never jump into the water to rescue them.
  • Encourage them to float on their back
  • Throw something buoyant so they can grab hold and stay afloat until they can be rescued:
    • Look around to see if there is a Life Ring.
    • See if there is anything you could use to help. Is there a fallen branch that you could pass to them to hold onto, a rope or even a football will help the person to stay buoyant.
  • Stay calm and talk to them and tell you have called for help and try and reassure them.
  • If the person is being taken rapidly downstream then try to get ahead of them.
  • Shout and signal to others for help