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Post by roseyrunner on Mar 19, 2010 0:37:23 GMT -5
Hi everyone,
I was just wondering if someone could explain to me the physiological reason why your heart rate will be elevated during cooldowns, even though you are running super slow.
For instance, say you do a 30' threshold workout. And you cooldown at a really easy pace, like 5 min/km. Normally my HR would be under 140 for that, but in cool down it will be about 160.
I imagine it has something to do with the increased demands of blood flow to compensate for something, but I'd just really be interested in knowing exactly what is happening.
Are any of you KNES students (or coaches) able to explain this?
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Post by Steller on Mar 19, 2010 5:35:10 GMT -5
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Post by ahutch on Mar 19, 2010 22:51:39 GMT -5
Different (but slightly related) question, in case Steller checks in again: what's the point of cool-down? Does jogging easily help accelerate recovery from the "oxygen debt" that EPOC is working against?
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Post by Steller on Mar 20, 2010 3:55:54 GMT -5
Ahhh Alex, --- I think you know you are asking a bit of loaded question here. There really is not much scientific evidence for the cool-down. (cool-down meaning lower-intensity post-workout exercise where you gradually brining HR back down to resting levels. Not meaning post-exercise ice baths/cold tubs – which actually have more scientific evidence).
I vaguely recall a study examining low-intensity passive exercise after intense intervals helping to more quickly clear blood lactate (between intervals—so light walking/jogging is better than just sitting between intervals, as blood lactate then pools in the legs more). However, if lactate directly causes fatigue is a whole other can of worms.
A cool-down has not been shown to necessarily reduce muscle soreness (very conflicting evidence) nor, does it have to do with “flushing” lactate to prevent muscle soreness (lactate has nothing to do with muscle sorness, as usually peak muscle soreness is 48 hrs after hard exercise, when lactate levels come back to normal in ~20min).
After really intense exercise (especially in the heat) cool-down, and doing some light exercise, does indeed help with post-exercise dizziness. Immediately stopping intense exercise can cause blood pooling and a vasovagal response, causing fainting. However, this is very individual.
Interestingly enough, several Africans I know do very, very little for cool-downs. They might run 45min in the morning before an afternoon workout, then do a 30-40min warm-up, then a long-training session, but then do 6 to 10min tops for cooldowns (not always like this obviously, but this is a trend I have been noticing).
I do think cool-downs, at certain times of the year, can serve as part of the workout and training stimulus (especially during the fall general prep phase). After a long-hard workout, when energy supplies are low in the muscles (low muscle glycogen), extending the cooldown (even though it is a slow-pace) can provide another stimulus to the muscle. It is a way to ‘sneak’ in some more endurance work, without even really realizing it. – but this has not been studied specifically—just is just a personal hypothesis (also based on some recent studies on training with low muscle glycogen). Anyone else think this?
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Post by journeyman on Mar 20, 2010 13:51:22 GMT -5
It is a way to ‘sneak’ in some more endurance work, without even really realizing it. – but this has not been studied specifically—just is just a personal hypothesis (also based on some recent studies on training with low muscle glycogen). Anyone else think this? Yes. I'm not sure of the science of it, but anecdotally, it seems that doing a little jog after workout makes you feel less sore the next day. I don't know why that is, or if it is really the case. Today I did a 2k rowing race. I warmed up with about 2k of easy rowing, then did the thing. My HR was pretty high, for sure. It felt about as hard as a good 1500 (a little longer though, 7:55, sr of 40per min). My legs were ok afterwards, but my arms felt like my legs usually do after a fast effort: burning with lactate or hydrogen ions or whatever it is that makes you feel the burn. I had to get to something else so I basically got off the erg, jumped in the shower, and got on the bus. I then sat down and wrote a 60min exam. So I did no cool-down at all, save walking to the bus. I wonder how my arms will feel tomorrow. Re: the original question, maybe it is because your HR was elevated from exercise and it hasn't come back down yet? Seems like a logical explanation to me. |
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oasis
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Post by oasis on Mar 20, 2010 15:05:30 GMT -5
I did an interval session today(5x1km) and times were slow as well as my HR at the end of each interval was 10 beats lower than normal when doing this type of session, anyone know why this could happen? don't believe I am sick or run down, maybe tired?
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Post by journeyman on Mar 20, 2010 15:11:33 GMT -5
Lower than usual HR can mean you are fitter. Or, as I learned from pq, it could mean you are hungry. (i.e. not getting enough fuel).
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oasis
Full Member
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Post by oasis on Mar 20, 2010 15:17:39 GMT -5
Lower than usual HR can mean you are fitter. Or, as I learned from pq, it could mean you are hungry. (i.e. not getting enough fuel). only my interval times were slower and found the workout more difficult than normal, nothing over the last while has given the indication that I am over doing it, training has been going well, as far as I know the lower HR with slower times it not good (basically common sense I know), obviously lower HR with faster times is ideal |
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Post by journeyman on Mar 20, 2010 15:30:34 GMT -5
In that case it could be tired or under fueled. If pq sees this he can explain it. I thought it was an interesting concept when he mentioned it before.
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Post by ahutch on Mar 20, 2010 15:57:29 GMT -5
Interesting stuff, Trent -- thanks for the thoughts. (I knew that I couldn't find any good studies on cool-down, but I wasn't sure whether I was missing something!)
I have to admit, on those rare occasions when I haven't been able to warm down after a race or workout (or, say, after the last race of a season when I don't care!), I've never noticed an appreciable difference the next day. I'm more likely to notice extra stiffness if I have to sit in a car for a long time right after the workout, even if I did warm down.
As for training stimulus, I've always figured that cooling down for more than five or 10 minutes was about adding mileage. (So going 25 minutes after workout three times a week gets you an extra 10 km/week beyond the "minimum.") There's just one group I trained with for a few years that really "worked" the cool-down. They (particularly the marathoners in the group) would run 5-7km after every workout at a pace that might get down to 4:00/km. After some of the tougher workouts, I'd be physically incapable of staying with them on the cool-down -- so they were definitely using it as a "train low"-type training stimulus.
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