The other day I was at my local sports club playing squash,
and at the end of the session, the instructor made a big deal out of cooling
down so we "won’t be sore tomorrow." While it’s not the first time
I’ve heard this advice, I always wonder where the instructors learn this bit of
incorrect information. I know they all mean well, but there is now quite a bit
of research that shows that a cool down after exercise doesn't prevent muscle
soreness. That's not to say the cool down has no purpose, it's just that
preventing soreness and speeding recovery isn't it.
A cool down often feels good, and the psychological relief
of riding easy, or walking around after a tough workout, can do wonders for
your mental well-being. But many well-designed studies found no amount of cool
down will prevent muscle soreness after exercise. In fact, studies show that a
proper warm up before exercise is more likely to reduce your post-exercise
muscle soreness.
So does the cool down have any benefits? Well, yes, there is
one major benefit: a few minutes of cooling down after maximal efforts can help
prevent an athlete from feeling dizzy or possibly passing out. What this means
is that you may not want to end your workout (or a spin class) with an all-out
sprint, maximal effort or a tabata session and then jump off the bike and touch
your toes. I once attended an exercise class where the instructor had us do
just that. It's a risky move when you consider the varying fitness levels and
health conditions that may be lurking in an exercise class. And for any athlete
racing in competitions, it makes sense to keep moving around slowly for several
minutes after you cross the finish line.
So far, the research has pretty well debunked the following
so-called benefits of cooling down
after exercise.
According to the current research, cooling down has little
effect on:
- Reducing muscle soreness after exercise
- Aiding recovery
- Increasing flexibility
- Increasing strength gains
- Preventing injuries
The benefit of cooling down after hard exercise is mainly
that it prevents the blood from pooling in the extremities after maximal
efforts, which can cause dizziness and fainting. By exercising at a slower
intensity for several minutes after a hard effort, sprint or maximal effort,
you'll allow your circulatory system to gradually return to a resting state
while maintaining proper blood pressure.
When an athlete faints or collapses after max efforts (or
when crossing the finish line), the most common cause is stopping so suddenly
that the blood pools in the extremities (usually the legs), and the brain is
deprived of oxygen for a moment. It’s called postural hypotension, and is the
same mechanism that causes you to feel dizzy if you stand up too quickly when
you have low blood pressure. Other less likely culprits for dizziness include
severe dehydration, a lack of sodium (hypernatremia), heat illness or heart
attack — all of which are fairly rare.
The treatment for postural hypotension is to simply lay the
person down, and raise her feet above her heart until the blood and oxygen get
back to the brain. If that doesn't solve the problem, then something more
serious could be going on, and medical help should be sought immediately.
Other common words of wisdom about the cool down say that it
will help you will recover faster and prevent soreness. The idea that cooling
down will reduce or prevent muscle soreness has not been found to be true with
research. In fact, what has been discovered is that muscle soreness after
exercise is caused by micro tears in the muscle fibers. Ironically, this is
also how a muscle gets stronger. After the small tears are produced, the muscle
tissue repairs and rebuilds itself (hypertrophy) and in doing so, gets bigger.
So by all means, continue to cool down after exercise if you
like. Just understand what a cool down can and can not do for you.
