Cool-downs - are they necessary? | EP#36

What are the real benefits and proclaimed benefits (aka myths) of cool-downs?

Should you do cool-downs, and if yes, how should you do it in your triathlon training?

In this Episode you'll learn about:

• The actual benefit of cooldowns: reducing risk of post-exercise dizziness and fainting
• Myths about cool-downs - no, they DON'T enhance recovery or improve performance in later workouts
• Why it might be a good idea to do cool-downs anyway - but from a training adaptation standpoint, not a recovery or performance standpoint
• My personal recommendations regarding cool-downs

Shownotes:

Cool-downs​

02:05 -

• In a nutshell, cool-downs can increase the rate of removing lactic acid and lactate from the bloodstream. This has been known to be true for a long time and has been one of the main reasons that people suggest to do cool-downs.​
• But what you should ask is, “Is lactic acid or lactate in the bloodstream after a workout really a bad thing? Is it detrimental to your performance in your workout?” The answer is probably not.
• Removing lactic acid from your bloodstream faster by approximately 20-30 minutes by doing a cool-down hasn’t been shown to give any benefit compared to not doing a cool-down at all. Lactic acid is dissipated from your bloodstream anyway after approximately one hour or so.

One proven benefit of cool-downs

02:48 -

• ​It reduces the risk of getting dizzy or fainting after working out or exercise.
• This is the only benefit that has been clearly shown by research. This is something that most researchers and exercise scientists agree on.
• In terms of performance and recovery, there are no clear benefits that have been shown.
• One great article on this topic from New York Times is an interview with Dr. Hirofumi Tanaka from the University of Texas. He concludes that the cool-down is an understudied topic because everyone thinks it’s an established fact.
• The studies that are available don’t tend to show that cool-downs are beneficial.

Cool-down myths

03:50 -

​1. It has been commonly believed that cool-downs prevent muscle soreness the following days.

• This is a myth.​
• Warm-ups do more to prevent muscle soreness in the following days than cool-downs.
• Muscle soreness is caused by micro tears in the muscles. This is essentially a mechanical stress. These micro tears are what allows the muscles to adapt and rebuild again to become stronger and more resilient.
• Lactic acid has nothing to do with muscle soreness. In one study, the researchers compared the muscle soreness during a 45 minute run in a group of runners. The ones who had the less muscle soreness are in fact the ones who had higher concentrations of lactic acid in their bloodstream.
• It used to be thought that lactic acid is a waste product that needs to be flushed away and dissipated. But there is no research indicating that this is true.
  
  There is research that indicates that lactic acid is flushed faster if you do a cool-down. But there is no evidence that faster dissipation of lactic acid is beneficial.
• In the New York Times article I mentioned, Dr. Tanaka said that there is another study in cyclists that concluded that lactic acid is good and that it is better not to cool-down after an intense workout because lactic acid is turned back into glycogen which the muscles use for fuel.
  
  This is in fact part of the reason why post-workout nutrition is critical for recovery - it's job is to restore your glycogen levels.
• Cool-downs have not been shown to aid in recovery either, with one exception. There is one study wherein the subjects did two 30-minute time trials on the bike on the same day. Then they compared 5 different versions of active and passive cool-down.
  
  With passive cool-down, they used things like a compression garment and ice baths. With active cool-downs they just used several slightly different protocols.
  
  An active 20 minute cool-down, at 35% of VO2 max, at 80 watts - which is a very low intensity for these cyclists, in Zone 1 - led to the best performance in the 2nd time trial.
  
  But two time trials in a day is pretty extreme and is not enough evidence for me that you should do cool-downs when you have more evidence showing otherwise.
• However, there is also no evidence that cool-downs are harmful or detrimental to performance or recovery. So you don’t need to stop doing cool-downs but just know that if you do them it's more so for making you feel good mentally but it doesn't really have any physiological benefits.

2. Cool-downs aid in relieving muscle tightness.

• There is no supporting evidence at all for this. There are no studies in endurance athletes but there are quite a few studies from soccer or football.​
• They found that cooling down after a football practice had no impact on the performance, flexibility, or muscles soreness the next day in professional football players.

Cool-downs reduce risk of dizziness and fainting after hard efforts

10:37 -

• The one positive benefit of cool-downs is not performance or recovery related. Rather, it is avoiding dizziness and potentially even fainting right after hard exercise.​
• Especially if you’re a high-level athlete, you may be vulnerable to this because you have bigger veins in your extremities for blood to pool into, and your heart recovers much faster back towards its resting state heart rate.
• When an athlete faints or collapses after a hard effort, for example, after crossing the finish line in a race, blood may suddenly pool into the extremities like the legs, causing the brain to be deprived of oxygen for a moment. This is called postural hypotension.
  
  This is the same mechanism that causes you to feel dizzy when you stand up too quickly when you have low blood pressure.
• The way to prevent this is by cooling down - by exercising at a very low intensity for a few minutes after a hard effort. This allows your circulatory system to slowly return to its resting state while maintaining proper blood pressure so that you will avoid the pooling of blood in your extremities and depriving your brain of oxygen.

More on the benefits of cool-down

​12:52 -

• This is based on an article written by Steve Magness who is a cross-country and track coach at the University of Houston, Texas, and the co-author of the book Peak Performance.
  
  (We had the other co-author, Brad Stulberg on Episode 28 Peak Performance - The Science of Success with Brad Stulberg, which is one of our most popular episodes to date.)
• In an article on his blog The Science of Running (which is also the name of a book that he authored) titled "Rethinking the cooldown", Steve mentions a few potential benefits of cool-downs. Although he mentions that none of these has been proven by research, these are some hypothetical muscle and endurance adaptation benefits:
• Practicing improved muscle recruitment. When you’re really tired after a workout, if you go for a 15 minute cool-down, for example in a run, you can (unintentionally) practise recruiting muscles properly even when tired, and maybe even recruit completely new muscles because you’ve used up your energy in your more commonly used muscles since they've been working hard during the entire workout. This may cause positive adaptations on a neuromuscular level, which is potentially very beneficial.
• Lactate utilization. Lactate is used as energy by the cells in your muscles. When there is a high amount of lactate in the bloodstream, your muscles might adapt and learn to use lactate more efficiently.
• Running efficiency. Practise maintaining good form even when tired during cool-downs. This is something I definitely think that - at least if you cool-down with presence and awareness, really thinking about your form and technique, can be a positive adaptation that may lead you to improve your ability to run, swim or bike more efficiently, even when you’re tired.

• Steve concludes that the cool-down might be a training effect more than a recovery enhancer. I definitely agree with this, as there is nothing to support that cool-downs are recovery enhancers in any way, shape or form.

Final important point

15:43 -

• If a cool-down makes you feel much better than if you don’t do a cool-down, then keep doing it because it’s not going to be detrimental by any means.
• It’s just that most of us age-group triathletes are very busy, and we want to train effectively. That’s what I want to try to facilitate in this podcast with the topics I bring up.
• And if you can reduce time spent working out by 10 minutes for every workout because you have been doing cool-downs that may not be necessary, then over the course of the week, and let's say for argument's sake you do 10 workouts per week, you can add the extra 10 minutes per workout (1 hour and 40 minutes in total) to your main sets to get greater training effects instead of spending the time on your cool-downs. I strongly believe that having that extra 10 minutes in the main set is going to do you more good than having it in the cool-downs.

Summary

16:32 -

• There is not much in favor of doing cool-downs in terms of evidence-based research.​
• The only benefit that has been proven is that cool-downs reduce the risk of dizziness and even fainting if you stop to a dead still after a hard workout.
• There may be several other benefits to cool-downs, but they are purely speculation at this point. However, they are valid theories in my opinion, so cool-downs may be beneficial from a training adaptation point of view.

Links and resources

• Send feedback to host Mikael by email
• Connect and hit me up on Twitter - my handle is @SciTriat
• Is the Exercise Cool-Down Really Necessary? by Gina Kolata, New York Times
• Episode 28: Peak Performance - The Science of Success with Brad Stulberg
• Blog: The Science of Running by Steve Magness
• Article: Rethinking the cool down by Steve Magness
• Warm-up reduces delayed onset muscle soreness but cool-down does not: a randomised controlled trial
• The Effect of Warm-Up and Cool-Down Exercise on Delayed Onset Muscle Soreness in the Quadriceps Muscle: a Randomized Controlled Trial