Afterdrop After A Cold Water Swim- Everything You Need to Know
If you’ve been cold water swimming or thinking about starting, then you have no doubt come across the term afterdrop. Well, what is afterdrop? Why does it happen? And more importantly how do you prevent it.
At the start of my cold water swimming journey many years ago I knew nothing about afterdrop. Now as an open water swim coach and experienced cold water swimmer, I’m hugely passionate about wild swimming safety. I want to encourage people to enjoy the cold water and show them how to do it safely.
What is Afterdrop?
Lets start with the sciency bit. Afterdrop is the phenomenon of a continued drop in core body temperature that occurs after being exposed to cold water. When referring to ‘core’ body temperature, this is the temperature of your vital organs (brain, heart, liver, stomach etc). Core cooling can continue after cold water exposure leading to afterdrop which can happen 10-30 minutes after you’ve exited the water. Many swimmers and cold water plungers experience afterdrop without realising it, but it can become dangerous if unmanaged.
Why Afterdrop Happens
It was originally thought that afterdrop was caused from cold blood from your extremities circulating back to your core after getting out of the cold water, but this has now been disproved.
It’s actually due to cold from your periphery (skin, subcutaneous fat and muscle tissue) continuing to radiate inwards leading to shivering and a further drop in core body temperature. In simple terms your cold outer layer continues to cool your core long after you have exited from the water.
Afterdrop vs Hypothermia
In very simple terms afterdrop is a process, hypothermia describes a state.
Afterdrop describes the continued drop in core body temperature, whilst hypothermia is the state of dangerously low core body temperature (below 35 degrees celsius). So afterdrop is a process that can lead to hypothermia if not addressed. Moderate to severe hypothermia requires immediate medical attention.
Symptoms of Afterdrop
If you are a cold water swimmer or dipper, then it’s important to be aware of the symptoms of afterdrop. Not just for yourself, but so you can recognise it in others as well. Keep an eye on your swim buddies. They may seem absolutely fine when they first get out, but can have problems 10 minutes or more later.
Afterdrop is one of the main reason why it’s not advisable to jump straight in your car and attempt to drive immediately after a cold dip and allow your core to recover first. Another great excuse to enjoy a warm drink and some cake with your swim friends following a swim!
The following symptoms can be a sign of afterdrop
- Excessive shivering. A little shiver is all part of the warm up process, but violent uncontrollable shivering might be the first signs of afterdrop.
- Feeling faint, dizzy or nauseous almost like you are “drunk”.
- Loss of coordination and mental confusion – often referred to as the ‘umbles’ (mumbles, grumbles, fumbles, stumbles).
If you or one of your swim buddies start to experience any of these symptoms, then move hastily with the following preventative steps, to prevent it from progressing.
How to prevent Afterdrop Safely
The best way to prevent afterdrop is to warm up efficiently. Get the outer layers of your body warm to prevent the cold continuing to radiate inwards.
- Get your wet stuff off as soon as possible and dry your skin. Don’t stand around chatting or posing for photos in your swim suit, even if you feel great when you first get out. Wet skin will cool further, especially if the air temperature is very cold or in windy conditions. So get your wet kit off pronto, cover up with a poncho or change robe and dry your skin by patting not rubbing.
- Keep your hat on. We lose a lot of body heat from our heads so to prevent this keep it nice and warm. If your hat is wet then obviously replace it with a warm dry one.
- Layer up. Have lots of loose easy to put on layers, with no tricky fastenings. These are impossible to do with numb fingers. A good trick is to have your stuff laid out in the order you are going to put it back on. This saves fumbling around in your bag looking for clothes when you’re getting colder. This includes outerwear like scarfs, gloves (I personally find mittens easier), wooly socks and fur lined boots that slip on easily. Finishing off with a waterproof and windproof outer layer, I love my dryrobe for this.
- Warm up gradually. Do this by getting dry quick and getting lots of warm layers on. Getting in somewhere warm (not hot) or a sheltered area to get out of the elements also helps. Avoid exposure to hot showers and car heaters on full that can cause blood to rush to the skins surface potentially slowing down core rewarming.
- Gentle exercise can help. By gentle I mean walking, moving your body not exerting yourself which may also slow down core rewarming.
- Stay hydrated and fuel properly. A warm (not hot) drink and sugary snacks work wonders. The science behind the benefits of a warm drink after a cold water swim is anecdotal, but it always makes me feel better. Shivering is energy intense, and cold water swimming burns far more calories than swimming alone, so it makes sense to give your body the energy it needs. Another great excuse to enjoy the post swim cake!
- Don’t push yourself. The idea of cold water swimming and dipping is to enjoy it, and the benefits come from just a few minutes of exposure, you do not need to push yourself to the limits of hypothermia to be a cold water swimmer.
In Summary
Afterdrop is the continued cooling of your core body temperature that occurs after you have exited the water following a cold water swim. It’s easy to prevent provided you plan your warm up correctly. It’s not something to be fearful of, but to be aware of to look after yourself and your fellow swimmers.
You may also find my article on planning your warm up after a cold water swim useful, as well as my essentials for after a cold water swim.
I hope you have found this article helpful, and please feel free to leave feedback in the comments. Here are some other very useful resources on after drop, hypothermia and cold water swimming.
Outdoor Swimming Society- Cold Water resources
Outdoor Swimmer- After-drop is real
RNLI- Top tips for Cold Water Dipping
Enjoy the cold water, but always safety first
Kerry x
