Afterdrop
What is it? What happens? Some examples.
As an open water swimmer you have probably heard of the term ‘afterdrop’ especially if you swim in colder temperatures. And even more especially if you swim ‘skins’ i.e. no wetsuit.
Oh, what's that, sorry…? You haven't heard of it?
Here’s @ben.stephens86 from Dunedin, one of the winter swim group ‘The Frozen SeaDogs’ showing, in exemplary fashion, how afterdrop presents. It will make you laugh. {Credit F.Lambrechts}
If you swim for a ‘long’ time in ‘cold’ water, after you get out and have dried off and struggled to get dressed as you have claw hand and maybe cramp in your stomach pulling your socks on, well, shortly after (about 10 to 20 mins), whilst you think you are on your way to warming up and thinking all is good, you can actually start to shiver. Possibly almost uncontrollably. And you will feel even colder. It’s this bodily reaction ‘after’ you are out and dry and dressed, coinciding with a further ‘drop’ in your body temperature. That’s Afterdrop. Ben displays it brilliantly as do many others!
Here’s the official googled type description: ‘Swimming afterdrop is a phenomenon where the body's core temperature continues to drop after a swimmer exits cold water. This occurs because the body’s surface (skin and extremities) is cooler than the core, and once the swimmer leaves the water, blood flow to the skin and extremities increases in a natural physiological effort by the bodies core to warm the skin & extremities, allowing the now cooler blood to return to the core, which can further lower the core temperature.’ Exactly what I said above.
So that’s ‘afterdrop’.
Let's go back to the earlier paragraph. I talked about ‘long’ time and ‘cold’ water. Those two terms are interdependent, subjective by person and totally depend on your practice and acclimatisation to the cold and atmospheric conditions.
I wear a wetsuit. I do that because I own a wetsuit company (lol), but it's still easy to get afterdrop. It just occurs after a longer time in cold water than without a wetsuit. So what is a long time? A ‘long time’ is dependent on body type and water temperature (and to some extent air temperature and if the sun is shining).
Talking personally, in a wetsuit (I don’t wear a thermal cap as I don’t suffer brain freeze and I don’t wear booties as they feel weird), I have a very good understanding via personal experimentation of what I can cope with (time in water / temp of water) to not have any appreciable afterdrop such that I can carry on a normal life post swim, rather than shiver for 1.5 to 2 hours and not be able to do anything!
That's the point for me personally. I really love swimming in cold water, which I classify at sub 11.0°C (51.8F). I like it. I feel good after my swim. However, I change the length of time I swim, depending on the temperature of the water and if it's sunny or not. I then convert time in the water to a distance, as I know my swim pace, so I gauge my ‘cold water swim’ on a distance I will be able to happily swim.
At 11.0°C I am happy for up to 45-50 mins; At 10.5°C (50.9F) I am happy at about 40mins; At 9.5°C (49F) I am happy at about 30-35mins. When I say ‘happy’ I mean, I get out of the lake feeling cold, but I carry on my day as normal. If I go appreciably past these times, at those approx. temperatures, it is going to take me a lot longer to warm as I will have some level of afterdrop. And remember, that’s me (5’10” 81kg) in one of my own design 5/4/3/2/1.5mm thickness Yamamoto neoprene with titanium thermal layer Ruby Fresh wetsuits. If I was doing the same without a wetsuit (which I wouldn’t) I’d be stuffed for half a day afterwards. It takes a long time to warm up when you get that cold. Again, those are my personal rough limits.
Swimming in Dunedin (with Ben & others) in early June (winter) I swam 26 mins at 7.5°C (45.5F). At these sort of temperatures, every minute counts. I found this semi unpleasant to the point of ‘why?’ It was Type 2 fun. I did have a few shivers after the swim but all cured with 3 pints at the Emerson's Brewery. At Lake Alta (1800m elevation) in the Remarkables mountain range in early May I swam 8 mins / 400m at 5.5C (41.9F). That was cold. Eight minutes was enough! But no afterdrop experienced with only 8 mins in the water, and with a wetsuit. Again, great Type 2 fun.
So, it’s not that I don’t swim in very cold water, I simply don’t want to! Much. Again, personal preference.
However it never ceases to amaze me what the body can deal with. Especially when I’m watching other people!
Let's now take members of the FrozenSeaDogs sea swimmer group, deep down in Dunedin, of which Ben in the video is a member. A number of the group only swim skins. Currently, the sea temperature is about 7.5°C. They swim on average for about 25mins (distance is not really relevant). I know this because I spy on their Strava activities {if you are on Strava, please join our Strava Squad}. It only takes a small temperature difference, up or down, to substantially change the length of time swimming. At 8°C, 30mins is the norm for them. Impressive. At 7°C that diminishes to 15-18mins. The point here is, seemingly tiny temperature changes, less than half a degree, are detectable by the individual and have an effect on time in the water. And those times, at those temperatures, with no wetsuit, result in differing degrees of afterdrop depending on the individual and their body type. Hence the fantastic video of Ben.
There is a ‘why’ - Dopamine. You don’t need to experience afterdrop to experience the Dopamine effect. But that is another article all-together…
Hey, it’s all fascinating stuff!
The idea with this article is to give some actual real life examples of the boundaries around afterdrop on-set rather than another super in-depth explanation of what afterdrop is and how to recover from it. And the effects of Dopamine. There are a heap of articles about all that.
Here’s a few:
https://www.outdoorswimmingsociety.com/warming-up-after-drop
https://loneswimmer.com/2023/05/28/a-complete-explanation-of-swimming-afterdrop
https://pubmed.ncbi.nlm.nih.gov/11043627
https://www.everydayhealth.com/wellness/possible-health-benefits-to-cold-water-therapy/
That is a nice segue into:
The New Zealand Ice Swimming Championships 10th - 13th July 2024