What is the purpose of cooling down?

Evening all

I get the point of warming up before exercise. It’s pretty much the same as a car: parts tend to be more brittle when cold so warming it up means you have less chance of damaging things etc.

But why does the body need to cool down slowly after a workout? My car doesn’t need to cool down after a race: I just switch it off.

I mean I know that the heart is still pumping fast so blood can pool and you can faint etc if you don’t cool down, but if the heart just returned immediately to resting pulse after the effort, blood wouldn’t pool.

If an answer is that muscles still require more blood after a workout than during their rest state, then the question becomes why do muscles still need more blood after the workout is finished? To wash away waste products? Why doesn’t the body just remove them immediately?

Why does my body need a cool down after a race, but my car doesn’t?

Many thanks


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I can tell you that if you race cars or drive spiritedly you definitely need to cool down a car too and not just turn it off. If your car has a turbo they can get red hot when driving hard and are cooled by coolant/oil that that is pumped through from the engine/radiator. If you shut it off while the turbos are red hot it is a recipe for disaster. (can cause cracking, burning oil/coolant off stuck in the lines clogging it and other things that can lead to turbo failures) Same for brakes as they can also get red hot during hard repeated braking. Your parking brake could fuse to the red hot rotor if it isn’t cooled down and you just stop and shut it off is another example.

All I know is if I’m really pushing it hard like a short TT or something and I just stop suddenly I run the risk of cramping if I don’t properly cool down (had that happen before after crossing the finish line of a 10 miler TT usually the first in the season where my pacing is poor and fitness is still lacking). For me without that cool down that lactic acid buildup doesn’t just magically feel like it’ll flush itself out anytime soon. But I’m not sports medicine doctor and I didn’t stay at a Holiday Inn recently either.


I always try to get in at least a 10min cool down after hard workouts. It reduces blood lactate back to normal levels. If you do a hard VO2max workout w/o cooldown the evening before a lactate threshold test (not recommended with or without cooldown!) your blood lactate levels will still be elevated when you start the lactate test…then they’ll go DOWN during the initial part of the test…then they’ll go back UP at LT1 and LT2.

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Short answer is that you don’t really need to. I rarely go beyond 5min simply because its what feels good.
Gerry Rodriguez doesn’t have us cool down in our swim workouts.
Matt Dixon the triathlon coach says in his books that it doesn’t matter much. Do it if you want and if it feels good.


“In summary, based on the empirical evidence currently available, active cool-downs are largely ineffective for improving most psychophysiological markers of post-exercise recovery, but may nevertheless offer some benefits compared with a passive cool-down.”


I like the race car example from above. It just keeps things moving and may aid in more active flushing of the metabolic byproducts in your muscles.

I also like it for the mental aspect. When I complete an intense VO2 workout I like the mental cool down of just spinning and letting my adrenaline, breathing, HR, etc get back to normal before trying to go upstairs and do normal life stuff.

I also think it is similar to post workout fueling. The sooner you have a workout following then the more important the cooldown is. So if you bike in the morning then run in the afternoon it may be more important to spin out your legs but if you don’t do a hard workout again for a day or so then it’s less important.


IIRC it was mentioned on the podcast that cooldown science is not that strong/supportive. which you can interpret as: it’s probably not a huge effect and may depend on situation/person.

with that, do what feels good?

from experience I know that just taking the HR down to recovery makes me happy afterwards.


Cool down help to remove lactic acid faster which mean better recovery.

I am a type one diabetic so my situation isn’t the norm but a cool down is a must for me. I wear a continuous blood glucose monitor so I get a real time indication of what my blood sugar level is. If I put in a hard ride and then just jump off the bike my blood sugar spikes. I don’t know if that relates to non-diabetics at all but that is my reasoning for a cool down.


For me, taking a cool-down long enough for my pulse to return to Z2 levels is critical to preventing exercise-induced migraines.

This is where I’m hung up. @Russell posted a study that shows the only major “benefit” to be reduction in blood lactate after active cool down, but under most circumstances I do not see why this is a benefit. Lactate clears from active recovery because it is used as energy, but if we just let the body do its thing, most of it will be converted back to glucose, meaning we don’t have to eat as much to make sure we are topped off for our next training session.

yeah to my knowledge that’s right–lactate levels return to normal after about an hour no matter what you do. So the explanation that it clears lactate = better recovery is probably wrong.

But that said, athletes all over the world do it, coaches tell you to do it, etc., so they must be on to something. My guess is that there is something that helps, we’re just not clear on what it is.

Maybe it’s not lactate but free radical oxygen molecules that get more effectively cleared.

Or maybe it’s something like easy exercise after hard exercise stimulates adaptations in your endogenous antioxidant system? If that were the case, you’re not getting better recovery in an immediate sense, but you would begetting better recovery in an aggregate sense, because you’d be fostering adaptations that over time would turn you into an athlete who recovers better.

Regardless of what the science is, a cool down almost always makes my legs fresher for the next ride.

If the main “benefit” of skipping the cooldown is that I can eat less, I’ll give it hard pass.

I like eating.

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I get this too. I think it feels worse to completely stop (fall on the floor gasping) than it does to spin the legs with little/no resistance.

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Lactate cause muscle soreness and fatigue.

With a proper cooldown, it will return to normal twice as fast.

Team Ineos must believe there is some science and performance advantage or they wouldn’t take exercise bikes to mountaintop finishes. That said I don’t know what that advantage might be. I ride at recovery level until my HR is down at zone 2 levels, but only because it feels good.

In the context of blood lactate, I would think you would only care to return it to homeostasis faster than what your body can achieve passively if you are in the middle of a workout or if you race two crits back to back, for example.

Depends how often you train.

Those who are training 6 days a week aren’t going to leave it up to chance that passive recovery will do the trick.

The Fast Talk podcast with Sebastian Weber this week was on recovery between intervals. There was a lot of discussion about what happens with lactate if you just stop spinning the pedals versus keeping pedaling.

For me, I like a bit of a cool down. From a practical point of view, I certainly don’t want to ride straight to my front door @ 90% of HRmax.

In the grand scheme of things it’s probably not a game changer either way.

But does this explanation make sense to you? First, even if it’s true, it means returning to normal after roughly 30 minutes vs. an hour. Does that sound like something that should make a huge difference in how yo ufeel the next day? Also, the relationship between lactate and the body is more complicated than your first statement would suggest.

don’t get me wrong, i love me a good cooldown. But i strongly believe the reason they are helpful is different than what you say it is

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