Tag Archives: swim recovery

What is post-exercise fatigue?

Edit: For all those of you who got this by email, WordPress just completely dropped all the formatting, for no reason I can understand, (but it happens occasionally), and you got a giant wall of text. Sorry!

It’s with trepidation I approach this subject. I don’t have the medical background that seems essential in trying to understand all of it so bear with me and any potential mistakes I’ve made.

Years ago I discovered the best questions were the dumbest questions, the ones where you are almost embarrassed to ask, but when you do, you discover more than you hoped to find.

After the two recent posts on the value of long swims and the post swim fatigue caused, I asked myself just what was the fatigue we all experience for a week or longer after long training swims (six hours and greater). It was such an obvious question I felt stupid by framing it to myself. What I found, in as far as I can tell, is that this is an area that is still very much being researched and not all the factors are known. Quoting this abstract on physical fatigue, “physical exercise affects the biochemical equilibrium within the exercising muscle cells. Among others, inorganic phosphate, protons, lactate and free Mg2+ [magnesium] accumulate within these cells. They directly affect the mechanical machinery of the muscle cell”.

As you will see, we could consider this one side of fatigue, that of muscles and the causes of muscle fatigue.

We know that endurance exercise requires energy and for distance swimmers this means first using the glycogen stored in muscles, blood and liver, and after that’s consumed, later switching to ketosis and starting to use fat stores. So there is an initial fatigue or tiredness caused partly by energy depletion. But 24 hours later, the body’s glycogen stores are pretty much replenished (but not entirely, depending on food type High Glycemic Index food replenished stores faster, type of sugar has an effect also, maybe even that the Golden Window oft referred to, isn’t relevant, and various other factors).

We also know, I think, that carb-loading works, and various strategies for carb-loading are better than others. On long swims, depending on effort, type of sessions and previous training, we may experience muscle soreness. Generally, if you are trained enough, this isn’t too common a problem and muscle soreness is a sure obvious sign of over-work. Part of the fatigue and recovery process is for muscles which have been worked to the point of breakdown to recover and the micro lesions get repaired. This is how muscles get bigger and/or stronger. When the exertion is enough, this may result in DOMS, delayed onset muscle soreness, that can last for a few days. DOMS is a whole subject onto itself, and it’s not what we’re concerned about here, but similar long-lasting effects without the soreness.

Muscle work is done by a process called the Excitation–contraction coupling mechanism, whereby an electrical discharge at the muscle initiates chemical events at the cell surface, releasing intracellular calcium, which causes calcium sensitive proteins to contract using ATP (Adenosine Tri-Phosphate, produced from glycogen or fat) ultimately causing muscle action. Lower ATP is part of the post-swim energy depletion mentioned above. However for long-term fatigue, the problem is not a lack of phosphate, but an impairment of the excitation–contraction mechanism, and possible other causes. This article, which is based on some actual studies such as this and this, says that part of tiredness, the inability of the person to make the muscles work to what they had previously, is actually also related to changes in the brain and communication between the muscle itself and the intra-cortical area of the brain. It seems like, (if I am reading it all correctly), there is a negative feedback loop operating between the two, with responses from the muscles during a tiring activity signalling the cortex to reduce the force (contraction) that can be applied. That mean it’s not just the muscle’s inability to function but that there is a central nervous system (CNS) fatigue also (whereas the muscular aspect is metabolic fatigue) and it seems that the CNS fatigue is the one that takes longer to recover from, that makes us feel low after long swims. On one study I read, (I seem to have lost the link for that one), it was found that immediately after stopping due to perceived exhaustion (on a cycling stress test), the muscles were still capable of exerting three times the work necessary for the test.

As this study says, “Fatigue from SDE [Short Duration Exercise] may arise primarily from metabolic mechanisms, whereas fatigue from LDE [Long Duration Exercise] involves an additional slowly recovering nonmetabolic mechanism that may arise from impaired activation, beyond the cell membrane, at the level of excitation contraction coupling”. Symptoms of CNS fatigue include lack of motivation, poor mood, impaired cognitive ability and incorrect perceptions of exertion levels –  where we think we’re exercising/swimming harder than we actually are. Sound familiar? The body needs rest and we need to avoid injuring ourselves. Fatigue cold (and has been) even described as a brain-derived emotion that regulates the exercise behavior to ensure the protection of whole body homeostasis. If we didn’t have fatigue feedback, we’d overuse muscles and probably injure ourselves but at the same time, endurance performance itself is limited by perception of effort as the primary reason for stopping. (More to come on this in another post,as so often happens when I start one of these science-based posts). Possible causes of fatigue, long-term and short-term:

  • DOMS
  • CNS fatigue (neurotransmission problems)
  • Insufficient hydration
  • Low insulin
  • Increased ammonia in blood
  • Disturbed hormone and electrolyte levels
  • Other nutritional (vitamin or trace element) deficiency
  • Low glycogen
  • Tryptophan depletion

This isn’t a comprehensive list, just what I’ve come across. I had to stop at some point. :-) I’ve found some impossible to understand (for me) speculation about potential mitochondria damage, and I’m sure there are other possibilities that are completely mainstream. This is all very well and interesting, you probably won’tsay, but what does it mean in terms of recovery? How can we shorten recovery or do it better or differently. Is there anything that helps? I think we’ll stop here, more study is called for, maybe we’ll return to this at some point. :-) There are no smilies in scientific papers.

Lane direction signs

Swimming through it – the value of long swims – addendum

Something was niggling at the back of my mind last week when I wrote the article on  the utility of doing longs swims, and what I’ve learned from them. I felt I’d forgotten something but couldn’t place it.

A question this week prompted me exactly what it was. Amongst the reasons for doing long swims is to get used to knowing how you feel after said long swims, and to understand and improve your recovery process.

After I wrote the article I happened to be checking something else in my swim diary/log, (which now has about five years of detail) and I noticed that almost exactly two years previously on the same weekend, 30th April, 2010, the Magnificent Seven did our toughest ever training session. It was to be a 30k in the pool followed by a trip to the sea for a swim. We completed about 28 kilometres in nine hours (including breaks) before The Boss left us off the hook, finishing strongly with 400 I.M. and at least as I recall, Liam, Eddie and myself ending with butterfly. My training dairy notes show I felt “strong and good”. And then we all decamped to Liam’s House at Ballycroneen for a sea swim taking about an hour to get dressed and get there.


For the Aspirants complaining of the cold this year … the water that day in 2010 was 7.5°  Celsius with onshore wind and overhead waves, and we’d come from the warm pool in Source. We changed in Liam’s garage and walked down wearing coats and I was quickly in the water, no point hanging around, having looked carefully at the breakers and headed straight for a Wave Channel I could see at the west end of the short beach. Eilís was watching on the beach, unusual for her to go near the coast.

I swam through the inside channel gap and duck-dived the outside waves and very quickly I was out back, beyond the breaking waves. By this stage I realised no-one had followed me. I played around body-surfing in the waves for a few minutes and headed back in. A couple of the guys were in shallow water, the rest were out, and everyone was shouting or giving out to me, all having thought I’d been lost at sea!

Ever since, Eilís has been suffering a type of cognitive dissonance, on the one hand knowing I understand waves and tides very well and  on the other, thinking I can’t be trusted around the water. Attempts to explain were ignored; that this was completely normal for my usual training since after all I had no-one to train with, that I made a point of understanding what I doing, and that getting through waves is easy if you understand the principles and that I had been a surfer for years, all were wasted. And the fact that there were six other extremely strong and experienced swimmers present that day was also lost on her. Ever since it’s been the day Donal could have drowned. :-)

But I digress, as usual.

The cold swim that day helped to loosen tight muscles but recovery from the long swim was slow over the next week. I wrote sometime back in 2010 that local Sandycove English Channel Soloist Danny Coholane had identified that every hour training over eight hours added another week to recovery, and we were all agreed on this (having previously swum six, seven and eight-hour training swims).

Swims of five to seven hours took about five days to a week to fully recover. The two training swims of eight hours that year took almost two weeks to recover.

So what do I mean by recovery? As I described in an email during the period there’s a feeling of having little energy or ooomph when you are swimming. Times drop away, swims become much more physically and mentally challenging, you feel like you have nothing in the tank. It varies of course for everyone, but I generally feel okay for a couple of days afterwards and the slump comes for or five days after the swim.

One thing I noticed this year is that extending the time above six hours to eight hours was no longer accompanied by an extra week increase in recovery, the slump lasted about the same time.

So feeling this slump is not the direct value of the long swims, but a side effect. The actual value is in knowing that this feeling is normal, and that you are also Training To Recover.  Too many people don’t seem to consider this aspect. Why go so far into your reserves for a Channel or other swim that you are done with swimming for months or up to a year afterwards?

Related articles

Swimming through it – the value of long pool sessions (loneswimmer.com)

24 miles in 24 hours (loneswimmer.com)

24 hour pool swim recovery

Well, I have to say recovery was pretty easy.

I had a tight chest on Sunday, and still somewhat on Monday. It felt similar in a way to asthma, but without the wheezing.

I did an easy 2k in the pool on Tuesday, felt really lethargic. I did the same on Wednesday but felt a bit better. Marie came in while I was there, feeling much worse, so we stuck to short 80% repeats.

I had a massage on Wednesday night from Vinny, which hurt wherever he touched. Every muscle was solid and felt brimmed with lactic acid. But it was the trick and yesterday I did 4k including reasonably fast 100s and today 4.5k including 10x 200s on 3:20 with plenty of time to spare. Deltoids still felt a bit sore but not enough to affect me. So I’d say recovery in four days, a lot different than a marathon swim.

I used my Magic Cups to ice earlier in the week, particularly my neck and over my shoulders and the tennis ball again for a few knots.

I think the extra stretching and use of the tennis ball in the middle of the night really helped.

Endurance Recovery

Part of the design of Eilís’ training regime was to enable quicker post-Channel recovery.

Given the extra work I had to do during the swim, the six hours extra duration over what I was expecting, I wasn’t sure how long before I felt recovered. Jen was definitely back before me.

I was also injured afterwards. And tired for at least three weeks. I would generally feel fine, but when I tried anything remotely strenuous, the tank was empty.

But the shoulder is now about 90% recovered, and only sore while swimming, and not very sore at that. Last week I got to the point where I wanted to swim,so I went back to the pool. And with easy days of only an hour, it’s enjoyable in a way it wasn’t back during much of the Channel training regime. My speed is even more mediocre. My aerobic capacity is not what it was not so long ago.

But I am recovered, I think. At least I won’t embarrass myself at Sandycove too much next Saturday. Eilís’ training proves itself again.

There’s an endurance sport adage that I came across in an old running book. For an endurance event you can do approximately two and half times your longest training event.

However, if you want to do it regularly OR want to recover well, then you must train longer.

Fascinating factoid from the experienced Channel swimmers

When we were talking the other day, Ciarán mentioned, that Danny Coholane (English Channel soloist) had told him and Eddie, (also English Channel Soloist) agreed…
…that every swim over eight hours mark requires a week to recover.

Ciarán also mentioned that he had been shattered for the week after the nine hour swim, meaning that all of The Magnificent Seven without exception had suffered that week after the swim.

It was such an important piece of info for long-distance swimmers, I’m giving it it’s own post!

Thanks Ciarán, Eddie and Danny Coholane !

9 hour swim recovery

So the day after the 9 hour, I was obviously tired. Didn’t have a great night’s sleep the night of the swim, something I’ve found previously when very tired.
Didn’t have much of an appetite during the day after. But I ate dinner around 5pm and it was like opening the gates to Gehenna. I ate an enormous dinner and just continued eating for the night.
Slept much better that night, and ate like a pig again yesterday, and again slept like a log last night. Still a bit tired today, but did a moderate 6.5 K ( 3 x 2k instead of 4 x 1k5 on the schedule) at easy cruising pace. Perking up nicely for the last 1K. Two hard days due before week end, long unbroken sessions.