Magness Speaks — Rethinking the Cool Down
The Cool down — what does it do?
I’ve contemplated for a while writing about the role and function of cooling down after a workout or race, but never I have never fully been able to put all the pieces together to do so. The cool down seems like such a normal/given thing. It’s a rite of passage to be able to be done for the day. It’s so ingrained that no one asks the question why anymore.
Let’s first look at the traditional viewpoint of the cool down. If we were to ask what a cool down is used for most answers would relate to bringing your body back to normal. You’d get answers like to get rid of lactic acid or waste products, to slowly bring muscle temperature down, to gradually reduce Heart Rate (HR), and all sorts of other related answers.
But do these things matter?
Lactate is cleared within 30-60min anyways, so maybe a cool down speeds it up to 15-20min, but that’s not a big deal because lactate is not evil. Muscle temperature and core body temperature would drop quicker by just standing around, as would heart rate. On the contrary a cool down would keep blood flow elevated for longer, so perhaps transport of “stuff” would be enhanced. But the truth is. We have no idea why the cool down actually physiologically does anything.
Is this another case of being overrated like stretching?
Everyone in the world uses a cool down post workout whether it is HS, college, or Pro’s so there has to be a reason or benefit. Unlike stretching (which people who were keenly aware just kind of stopped doing) there’s never been a movement to stop cooling down. That to me, and the fact that empirical evidence from coaches all over supports the use of one, lends credence to the idea that cooling down is in fact a good thing. My contention though, is we’ve been asking the wrong question when trying to figure out what a cool down does in the running world.
Adaptation, not always recovery
While the emphasis on what a cool down does has been on returning to normal and recovery, which it probably aids to a degree, I can’t help but think that we’re missing part of the picture. The cool down job or activity post workout is actually part of the workout. It’s a crucial component that actually furthers adaptation.
What state is the body in at the completion of the workout? We are probably left with muscles running low on glycogen, high on lactate, have a low pH, a large number of muscle fibers having cycled in to do work and exhausted, all sorts of neurotransmitters in the brain at high levels, and the brain’s central governor screaming at us to stop. That’s quite a lovely state to be in right?
Once we stop, things calm down a little bit and start the return back to homeostasis. But then we start jogging again and what happens?
We’re now doing more running, albeit at a slow pace, in this depleted state. It’s not increasing our depleted state too much in most cases but we’re still recruiting muscle fibers to work when they’re in this state. Is it possible that with a ton of them already fatigued, we’ve altered the recruitment slightly so that fibers that normally don’t work at such an easy aerobic intensity are now working? If so, then we’re training fibers that normally don’t work at such low intensities to be a little better aerobically. Secondly, if we look at lactate. If we have a decent amount of it built up and we start running, are we perhaps training our muscles to take up and reuse lactate better while running then if we were just lying around?
If we look at the brain’s role, could continued exercise, even at a low intensity post hard workout actually signal the brain that we’re okay and we can push these boundaries a little bit more and survive?
I don’t know the answers exactly, but…
What I’m getting at should be obvious but it is this: The cool down might be a training effect more than a recovery enhancer. Both probably play a role, but it’s typically thought of as the later only.
Where’s the evidence? I have little because there is little to no research on cooling down.
What I do have though is intriguing
We know that a cool down of aerobic exercise (i.e. a jog) following a strength workout will impact the adaptations that occur from the total workout. Depending on the combination and what kind of athlete you are dealing with, a cool down can either enhance strength gains or be used to limit hypertrophy. Essentially throwing aerobic exercise in after a strength session can impact the adaptations you get. You can see this on a signal pathway level in comparing what pathways get activated versus which don’t. Just by including light aerobic work after (which many would consider a cool down) can alter the effects of the previous strength workout. Similarly, there have been some intriguing studies on stretching after strength work that shows it can change the amount of hypertrophy. The point is this, a cool down activity can modulate what the main workout produces in terms of adaptation.
The cool down therefore should be looked at as an enhancer to the main workout.
How to modulate?
I have no clue. I’m guessing. Completely. Educated, but still guessing.
So let’s look at our options beyond a typical short jaunt. Remember that we are in our kind of fatiguedstate at the start of the cool down…
Long cool down
Simply go for a longer cool down. Instead of the easy 2mi or so, go for 4,5,6mi. This is what we used to do in HS after races. Why? Partly to get in mileage, partly for no reason, and partly because we went really slow so we could get the girls on the team to run with us and cause mischief…but it was mostly for the putting in the extra miles…
So what could a longer cool down for you? You’re getting a light aerobic stimulus on fatigued muscles, meaning your probably training some fibers aerobically which normally aren’t. Secondly, you are dampening down the effect of something highly anaerobic if you do it after a anaerobic event (think 4×400 or a very fast speed session). This is briefly touched upon in Jan Olbrecht’s wonderful book Science of Winning. Why would you want to dampen down the effect? If you have a kid who is a high responder to anaerobic work and you don’t quite want it overwhelming the aerobic side of things.
Strides in cool down — One of the more intriguing cool down manipulations I experienced was a set of 10x100m strides with a turn around recovery as part of the cool down from a hard track session by Igloi disciple Joe Douglas. Why might this be good? Well two thoughts. First, it’s not long but its faster so once again your pushing activation of muscle a little more in a fatigued state. Secondly, you’re going through a bigger range
of motion running wise, so it prevents that tightening up or change in tension too much.
Stretching cool down — As I mentioned before, in combination with strength training, while there have been only a few studies, stretching sometimes enhances strength performance. The theory is mostly based on the idea that the combined effect increases hypertrophy. Another possible mechanism is that stretching seems to increase select hormones, at least in animal models, such as IGF-1 (Yang et al. 1996). What does this mean? That stretching AFTER a workout might do something. Right now there’s slight evidence for increase in hyprtrophy. Remember that when stretching you are actually essentially tearing collagen bonds, so its possible that the adaptation occurs via a response to damaged tissue. So lots of questions to answer. Do we stretch for hypertrophy post workout if that’s the goal? Do we stretch to get a hormonal response to increase recovery? Or should we avoid stretching because it may increase damage to a muscle tissue that’s probably already damaged from the workout?
Strength in cool down — Last but not least what about adding strength to the cool down. Whenever I trained out in Virginia with Scott Razcko we always did GS (general strength) right after runs/workouts. I think this is intriguing for two reasons. First, it has to be a great way to work on strength endurance. Think about it. You’re adding a strength component in a pre-fatigued state. Secondly, what happens hormonaly? Depending on the strength exercises selected, is it possible to get a hormonal change that enhances either adaptation or recovery?
And what about recovery?
Yes. Cool downs likely help recovery for feeling good the next day. Why? Well no one knows for sure. The increased blood flow thing for a while is one theory that makes sense. There could be a hormonal component. Then you have canova’s data where he stated that after an easy run you can get lower morning lactate levels. But one of my thoughts is this: a cool down simply manipulates tension in the muscle. You go from doing
something hard and fast which will eventually jack up tension, and a cool down simply works to modulate that down a little bit. It’s why you probably feel better the next day if you cool down instead of going straight to the car…
Is there ever a time where you don’t want to cool down?
At first this seems blasphemous, but stop and think about it. Could there be a time when you don’t want to? It’s probably few and far between but would not cooling down give predominance to some anaerobic adaptation post “anaerobic” workout? I’m not sure I have the answer but it’s an intriguing question to think about.
The take away here is that we don’t have a lot of answers, but we do have a lot of intriguing possibilities. It’s time to change the way we think of a cool down. It should be another planned part of the training in certain situations. Once you shift it from being solely a part of recovery and instead see it as a way to manipulate adaptation, then questions arise and possibilities open.
*note: a previous version of his post was originally published by Steve Magness on The Science of Running on Sept. 9th, 2012. It has since been very slightly updated.