Getting the cool-down right

Several years ago I wrote about getting the warm-up right, and I still believe that many runners neglect the warm-up to their own detriment. But after you work out, what about the cooldown (or, less commonly these days, a “warm-down”)? How long, how far, and how fast should a cooldown be? Getting to a place where we can answer these questions is going to require getting a framework in place where we understand why you should cool down in the first place.

Understanding the reasons for doing a cool-down after a workout

Like much of the accumulated lore of running, the common rationales for doing a cool-down at all contain a healthy mix of physiology, bro science, folk wisdom, and true coaching wisdom. Allegedly, the cooldown is supposed to gradually reduce your heart rate, pump “lactic acid” out of your muscles, and condition your legs to running while tired. Failing to cool down is again allegedly supposed to make you feel more sore the next day, and harm your recovery capabilities. Needless to say, each of these rationales has a hefty amount of myth alongside perhaps a kernel of truth.

Instead of trying to consider and analyze each of these claims in turn, I think it’s better to break the question of “why do a cooldown” into smaller parts: who is doing the cooldown, what workout does it follow, and what training goals are we trying to accomplish, both in this workout and in the longer-term training plan.

1. Who is doing the cooldown?

Even for two runners doing the same workout, it might be appropriate for each of them to do a different cooldown. Factors like age (both biological and training age) and injury susceptibility influence what kind of cooldown is optimal.

Younger runners should cool down differently than older runners

First off, your level of running experience has a big impact on what kind of cool-down is appropriate. Let’s start at the very young end of the spectrum–I spent a season at Edina as the head middle school cross country coach. That fall, I was working with runners who were young both chronologically and in terms of their training age–very few had ever run before, and certainly not in any kind of structured way.

For young, inexperienced runners, the primary benefit of a cool-down is structure: it helps reinforce the notion that practice generally, and workout/race days specifically, are comprised of a structure of things (e.g. team meeting, warm-up jog, drills, strides, intervals, cool-down, and a check-in before heading home) that we do every time, no matter what. Building up comfort and familiarity with a structure for training is extremely useful, because later on in your running career this structure can help pilot you through challenging circumstances, like extreme anxiety before a big meet, or disappointment and frustration after a poor performance.

Another benefit for young runners is that cool-downs provide more aerobic running. When you early on in your running career, more aerobic mileage is pretty much always beneficial, regardless of the form in which it’s delivered. However, younger runners are also generally going to be doing less mileage than older runners, so this pushes in the direction of doing less total cool-down.

Older runners get less aerobic benefit from a cooldown

Once you are a few years into your running career, you’ve already gained a lot of the low-hanging fruits of improvement from general aerobic running. By “general” here I just mean “non-specific”—jogging around the infield after a track race isn’t really stimulating any specific aspect of your aerobic fitness. This is fine if you’re 16, but if you’re 26 and have been training seriously since high school, your body will not respond much, if at all, to these kinds of general aerobic stimuli. You need specific, targeted aerobic stimuli to improve, which generally means long, fast running–the kind you’d do in the workout proper, as opposed to part of the cooldown afterwards.

Injury-prone runners should do a shorter cool-down

If you are trying to limit a runner’s mileage for injury-related reasons, the cooldown should be the very first thing you should reduce (or even eliminate). First, as discussed above, it is only providing a general aerobic stimulus, as opposed to a race-specific stimulus, so (even for younger and less-experienced runners) its importance is secondary to that of race-specific training. Second, when you are cooling down, you are doing so on tired and damaged legs. In that sense, you are encountering additional mileage when you are at your most vulnerable. The injury risk associated with cooldowns can be ameliorated to some degree by doing it slowly, but again–this makes it merely a general aerobic stimulus.

2. What kind of running workout are we cooling down from?

Much of the traditional justification for cooling down has to do with the cool-down’s purported ability to remove metabolic byproducts (“lactic acid” being the often-misused label here) from your muscles and from your bloodstream. I suspect there is some truth to this, so it’s worth considering the metabolic milieu inside your muscles and bloodstream after a workout.

Do longer cooldowns after faster interval workouts

If you’ve just completed a fast interval session (or “HIIT” session as you might hear it called elsewhere), there are two distinctive differences in the physiological state of your body. First, your muscles are bathed in metabolic byproducts like hydrogen ions, lactate, and calcium ions, plus probably some smashed-up bits of muscle that were damaged during the workout (creatine kinase, a biomarker of muscle damage, increases markedly following fast interval workouts). Second, your blood contains many of these same metabolic byproducts, because they are diffusing from your muscles out into your bloodstream.

The cooldown can function as a way to keep your blood circulating, which should help at least some of your body’s recovery systems do their job. Excess lactate, for example, can be metabolized by the liver and the heart, so keeping blood flow going should accelerate this process. Indeed, research bears this out: “active recovery” following high-intensity intervals increases the rate at which lactate levels drop over the 10-15 minutes following a workout [1].

Blood lactate levels drop faster if you use “active recovery” (i.e. a cooldown) versus just standing around after a workout.

So, there’s a good justification for cooling down after fast interval sessions that generate a lot of metabolic byproducts. However, what about workouts that don’t generate a lot of metabolic byproducts, like Daniels-style cruise interval workouts, marathon pace workouts, and Canova-style long fast runs? In this case, much of the justification for a longer, traditional cooldown falls apart.

These sessions are already a big, specific aerobic stimulus to your body, so the added benefit of a bit of slower running is minimal or nil. It’s wiser to do a short jog of just a few minutes at a very easy pace to cap off these kinds of workouts, then call it a day. This will keep your blood flow up for a few more minutes but won’t put any extra stress on your legs, which already sustain a lot of damage on high-volume aerobically-oriented training sessions.

3. What are we trying to accomplish in training, both short-term and long-term?

The final thing to consider when choosing a cool-down is what our training goals are, both for today’s workout and over the long term. When it comes to short-term goals, getting some aerobic stimulus from a cooldown is going to be more relevant when the focus of the day’s workout is not on aerobic fitness. This might seem paradoxical, but keep in mind the distinction made earlier between a specific stimulus to aerobic fitness (like a 6mi aerobic threshold run) versus the general aerobic stimulus of a cool-down. After an aerobic threshold run, the marginal aerobic benefit of a cool-down is negligible, but that’s not necessarily the case after a session of 600m repeats at 3k pace, whose focus is not on purely aerobic fitness.

In terms of long-term training goals, we should also consider things like mileage goals, managing injury risk, and whether we are focusing on building overall fitness through consistent daily training, or are trying to generate a big, specific stimulus to the body, then recover well afterwards. For a beginner or intermediate runner early on in a training cycle, hitting a weekly mileage total is going to be a much bigger priority than a more experienced runner who is six weeks out from a marathon and has just completed a long fast run at 95% of marathon pace, and hence the beginner would do a longer cooldown (if necessary for a mileage goal) than the experienced runner.

Long cooldowns usually do not make sense

Among runners trying to hit certain mileage targets, you’ll commonly see cooldowns of 5-8 miles after workouts or races. In most cases, I am against this. First, you’re putting quite a lot of volume into your legs when they are at their most vulnerable. Second, workout or race days are trying to accomplish a different thing in training than an easy run, and I think it’s generally a mistake to conflate these.

In most cases, I’d rather have the athlete in question do a double the same day, or adding more mileage to other days of the week. This creates some separation in the training stimulus between sessions, though there are some cases where a moderate-length cooldown (maybe 4 or 5 miles) makes sense, especially for higher-mileage runners who are doing early-season track races. I illustrate an example of this below.

Another alternative I like more than long cool-downs are post-race workouts. I would have sworn I wrote a blog post about this, but it looks like I haven’t! I put these in a different category than mere cool-downs, so we’ll leave that topic for another day (and hopefully I will remember to add a link here once I’ve written that post).

Some examples of more effective post-workout cooldowns for runners

The conceptual arguments above might seem a little abstract without some concrete examples of runners of various experience levels at different points in their training cycle and in their running career. These are fictionalized, composited, and semi-hypothetical versions of real runners I have worked with in the past, with names and some identifying details changed:

Athlete: Matt, 16 year old male, 9:50 3200m PR

Workout: 5x1200m at 96-102% of 5k pace

Cool-down: 10min easy run + 10min easy jog barefoot on grass or turf

This workout is a pretty typical “specific endurance”-type session you might do in April of an outdoor track season ending in June. This athlete is young and talented, and with no history of significant injury, so our eye should be towards setting up a foundation for better performance in the future. That’s the rationale for (1) doing a somewhat longer cooldown, and (2) doing some of it barefoot, as a way to get some ancillary benefits for foot strength.

Neither of these things are likely to affect this runner’s performance this year, but can be a foundation to build on later. There’s a slight aerobic benefit to keeping the pace honest at least for the non-barefoot part of the cool-down, and since the workout is going to generate a decent amount of lactate, we do want a cool-down of a reasonable duration to start reprocessing that and other metabolic byproducts.

Athlete: Alex, 25 year old female, 1:20 half marathon PR

Workout: 11 sets of (1km at 100-103% HM, 1km at 90% HM)

Cool-down: 8-12min easy jog

This is a half marathon-specific session that you might do six or eight weeks out from your target half. It’s a fairly high volume session already, and though it will generate a bit of lactate especially in the final few fast kilometers, the amount will be pretty small compared to Matt’s workout.

The intensity of the cooldown is immaterial—the workout itself is already a big aerobically-dominated stimulus, so this can be as slow of a jog as desired. The duration can be tuned a bit to help hit mileage goals, but on a session like this I definitely would not do more than 15 minutes, even for a very high mileage runner.

Athlete: Gabby, 18 year old female, 4:54 1600m PR

Workout: 800-600-500-300-200-200 at 2mi→800m pace

Cool-down: 12min easy on stationary bike or 8-10min easy on AlterG

Gabby is a very talented runner with a recent history of stress fracture and some nagging pain in her ankle. This is a session we might do a few weeks out from a major track race. Since this would be at the end of her senior year of high school, the focus here is entirely on avoiding any extra biomechanical stress on top of the workout itself (which is itself designed for maximum benefit / minimum volume*intensity).

The stationary bike provides the ‘active recovery’ needed to reuptake metabolic byproducts, but without the biomechanical stress of extra mileage. Notably, the stationary bike is included here because this is something Gabby would be familiar with, having used it to cross-train during her injury. You don’t want to have a runner suddenly start using the stationary bike right before a big meet if she hasn’t been using it recently. If available, an AlterG would be a fantastic and more running-specific alternative.

Athlete: Trevor, 38 year old male, 3:20 marathon PR

Workout: 16 miles at ~90% of current marathon fitness, or ~80% of current 5k fitness

Cool-down: None

Trevor runs 40-55 miles a week, has a busy schedule, and wants to break 3:00 in the marathon. To reach his goal, he needs to lean on marathon-specific work to a greater degree than his higher-mileage peers. This is a classic “long fast run,” which we might do around 12 weeks out from the marathon.

Trevor would already be comfortable doing 19-20 miles at an easy effort, and will have done previous long fast runs at this same speed but 10, 12, and 14 miles in duration, spread out over the past several weeks. After finishing this run, Trevor’s legs have received a pretty good thrashing, and his cardiovascular system just got a huge aerobic stimulus, with little to no lactate generation. Here, the benefits of a cool-down are pretty much nonexistent—so we just don’t do it!

Athlete: Natalie, 22 year old female, 2:07 800m PR

Workout: 3x450m at 98-102% of 800m pace w/ 6-10min rest

Cool-down: 15-20min very easy jog

This is a classic 800m-specific session that is going to flood the body with lactate. To set ourselves up for recovery, we want to get a good solid cooldown at a very light intensity. There’s little aerobic benefit to be had here (and aerobic fitness is not at all the focus of this session) so the speed does not matter on the cooldown. Fast mid-distance runners like Natalie may nevertheless prefer to cool down at a faster pace, just because the mechanics of running, say, 7:30 mile pace feel more comfortable for her than 8:30 or 9:00 pace.

Athlete: Christopher, 13 year old male, 5:35 1600m PR

Workout: 10x300m at 5k-ish effort, 100m walk or jog recovery

Cool-down: 12min easy run on track with faster teammates

Workouts for middle schoolers can’t usually be structured as well as those for high schoolers and beyond. Beyond “start this workout at 5k effort and try to get faster,” there’s little benefit in trying to prescribe specific paces, since middle schoolers often aren’t able to pace themselves very well and you have a lot more variation in running ability with this age group.

It’s better to choose workouts that naturally encourage consistency. 300m reps with a 100m recovery are one of my favorites, since more fit runners can jog the 100m and less fit runners can walk it (if you make them all jog the recovery, slower runners can’t do the 300m much faster than their recovery jog!). The “cool-down” here for Christopher is really part of the workout. By running with faster teammates, probably at a pace faster than he’d go even for his easy runs, he gets a much-needed additional aerobic stimulus that will help him improve over the long-term.

Christopher also benefits from the structure of doing a cool-down. Even if he just slogs around at a barely-above-walking-pace talking with his friends, he’s still learning that all workout (and race) days have a common structure: a warm-up run, mobility drills and strides, the workout or race itself, and a cool-down jog. When Christopher is a senior in high school and is running at the state cross-country meet, being able to ‘run the script’ is going to be immensely useful for dealing with the stress and anxiety of a big meet.

Athlete: Joe, 28 year old male, 31:40 10k PR

Workout: 20mi at 95% of target marathon pace

Cool-down: 4min very easy jog

This long fast run is one of the final ‘capstone’ workouts you’d do during a block of marathon training, with this run happening 3 or 4 weeks out from the goal race. Joe is a talented athlete who’d be looking to run close to 2:25, and he’s comfortable with 90+ miles a week, but even for him, this is one of the toughest sessions he’ll do during this training cycle. The cooldown here serves no real physical benefit, but a few minutes of easy jogging serves as a good opportunity to psychologically decompress after nearly two hours of focused, high-intensity running.

Athlete: Camille, 17 year old female, 10:50 3200m PR

Workout: 1600m indoor track race

Cool-down: 30-40min easy to moderate w/ 5x25sec strides in last mile

Camille is a long-distance specialist who has built up to 50-55 miles a week over the winter, and is doing an early-season indoor track race. A warm-up and typical cool-down is only going to total a few miles, and only one mile at a fast pace isn’t much of a stimulus to the body in any direction. This is one case where a long(er) cooldown makes sense. Notably, this would also be a good opportunity for a more formal post-race workout—something like 6x3min at the anaerobic threshold with 50-60sec jog recovery would be a good choice too.

Recap: A principled approach to cooling down after workouts

Are cooldowns going to make or break your training? Probably not. Still, it’s worth having a principled approach to how you structure them, and to understand when and why you do them. John Kellogg once likened the benefits of sprint drills to choosing the right spices for seasoning for a meal. Do you still get most of the nutritional benefits without seasoning? Sure. But with just the right choices, you augment the benefits of the meal in a way that’s both tasty and more nutritious.

So too with cool-downs: being thoughtful about the cooldown helps you understand what you’re trying to accomplish in training, and the right choices can set you up for long-term success in running. Keep in mind the various roles a cool-down can play: adding structure to a young runner’s training, keeping blood flow high to flush out metabolic byproducts after high-intensity sessions, serving as an additional aerobic stimulus to the body, and putting (sometimes undesirable) additional biomechanical stress into your legs.

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