May 3, 2012
Cold-water immersion for preventing and treating muscle soreness after exercise.

Taking ice baths post-exercise seems to be the most popular method of reducing delayed onset muscle soreness for novice and elite athletes.  This method, known scientifically as cryotherapy, is growing to be more popular than traditional ones such as massage, stretching, or taking non-steroidal anti-inflammatory drugs (NSAIDs).  The most popular forms of cryotherapy are cycling 1 min in ice water (5 degrees Celsius) followed by 1 minute out for a total of three times or a longer duration of 15 minutes at 15 degrees Celsius.  Now that you have the background, I’ve went out and found an enormous extensive review on the subject to make clear whether or not this technique is useful or useless at combating muscle soreness and aiding recovery.

The scientific claims:  You know that you treat sprains, strains, or any swelling in the body with ice.  The mechanisms for why cryotherapy works are similar; reduce pain, swelling, and inflammation.  There is also vasoconstriction (decreasing the diameter of the blood vessel) which stimulates blood flow and nutrient and waste transfer as well as decrease in nerve transmission speed, which could alter the threshold of pain receptors.

The studies used:  The review included 17 small trials (published from 1998-2009) of 366 participants.  No restrictions were placed on age (16-29), gender female, or type of level of exercise.  Also, no restrictions were placed on duration or frequency of immersions or depth of immersion.  The studies were all of small sample size (20 participants or less) except for one that used 54.

The exercises used:  All exercise used were designed to produce delayed onset muscle soreness (DOMS) under laboratory controlled conditions.  Repetitions for resistance exercise ranged from 50-100 of eccentric or alternative concentric and eccentric contractions.  The other studies used running or cycling in single bout efforts (for the bike) or steady state efforts.  Few actually included team sport exercise (basketball and soccer).

The cryotherapy used:  The most common for the studies was 10-15 degrees Celsius with an average immersion of 12.6 minutes.  This was employed in almost all of the studies immediately after exercise.  The different methods of cold-water immersion were compared to nothing/rest (the most common), cold-water immersion vs. contrast immersion (switching between hot and cold), cold-water immersion vs. warm water, and cold-water immersion vs. active recovery.

Enough with the technicalities.  Let’s go to the results. 

Cold-water immersion vs. nothing:  In terms of muscle soreness, there is no significant difference immediately between the two conditions but at 24, 49, 72, 96 hours later the cold-immersion group reported a significantly lower amount of muscle soreness than the group that just rested.  This effect seems to be more prevalent after running based exercises than resistance exercises but the authors not that due to the various types of exercises that were performed between all the studies, plus the sample sizes being small, it is difficult to find whether or not this is truly significant.  There were no significant differences in strength, power, functional performance, swelling, or biomarkers of muscle damage.

Cold-water immersion vs. contrast immersion:  In terms of muscle soreness, there was no significant differences between the groups.  Also, there was no significant differences in strength, power, functional performance (time to fatigue), swelling, range of movement, or biomarkers of muscle damage.

Cold-water immersion vs. warm-water immersion:  There was significant lower levels of muscle soreness reported only for the cold-water immersion group at time-point 96 hours with no differences in strength, power, functional performance, swelling, or biomarkers of muscle damage.

Cold-water immersion vs. active recovery:  There are no significant differences in reports of muscle soreness, strength, power, functional performance, swelling, or biomarkers of muscle damage.

Discussion/Conclusions:   Cold-water immersion did significantly reduce muscle soreness at time points 24, 48, 72, and 96 hours post-exercise.  However, it is important to note that these were all subjective reporting (self-reports) and the authors state it is hard to draw true conclusions from the data due to poor methodological quality.  There were high risks of bias due to the fact that blinding was performed poorly as well as concealment of group assignments (only 1 study did this effectively).  There were also large differences in the types of exercises used and subjects were a mix between trained and untrained.  The effectiveness very well may rely on the specificity of the exercise performed as well as the athletic level of the individual.

My input:  Did you know that in the 1920s, cyclists in the Tour de France would smoke during the race because they believed that smoking opened up the blood vessels and oxygen transport machinery of the lungs?  Ridiculous, right?  I’m not saying ice-baths are as crazy as this, but are they truly beneficial to aid recovery in the muscle?  I’m not so sure.  From the most basic laws of chemistry, we know that when something is heated up the molecules in it move faster and when something is cooled down the molecules in it slow down.  If you are exposing your muscles to cold, all of the molecular processes will slow down.  You need enzymes (which function effectively at specific temperatures) and proteins moving post-exercise to begin the repair process and signal inflammation, and if you’ve read my previous posts on muscle hypertrophy, you know inflammation is necessary.  It is the same reasoning to avoid NSAIDs in hopes of reducing muscle soreness.  For this reason, I’m always heading for the exact opposite after training, a hot shower.  The reason I do this is not only to continue normal biochemical processes in the muscle but also to incorporate the activation of what are called heat shock proteins.  Heat shock proteins are proteins in the body that respond to stress or elevated temperatures.  They function as chaperones for other proteins by aiding them to conform to a certain shape and stabilize proteins that are not shaped properly.  Basically, they can clean up the mess inside of the muscle cell and help with repair.  This is another reason why I’m not on the ice-bath bandwagon.  You might feel that it has helped you before in the past and it possibly could have helped, but I just want to let you know there is no scientific evidence supporting it.  The studies are low quality studies.  If you truly want a good study on this, take a group of at least 35 people, train their legs or their arms simultaneously with the same protocol and put one limb in the ice and one limb not in the ice or in warm water, take muscle biopsies, and see the differences between the conditions (Anyone want to take this on as a nice Master’s or PhD project? I’ll be glad to give advice for it).  To my knowledge this has not been done and this would be the best way to see if cold-immersion truly helps.  Although there was some evidence in a decrease in self-reported muscle soreness, I’m still not convinced and higher quality studies are necessary before I’ll be convinced.

Bleakley et al Cochrane Database Syst Rev. 2012 Feb 15;2:CD008262.