The Kendo Teacher. 1941. Wada Sanzo. From the series Japanese Vocations in Pictures.



Feeling the Heat

Here is a fun fact to consider.  The modern mechanical air conditioner was invented by Willis Carrier (a Cornell graduate I might add), not in Arizona or Florida, but in western New York state.  It may come as something of a surprise to learn that Buffalo, best known for images of apocalyptic levels of snow, is the home of AC.  We are not exactly in the sun belt, but every year central and western NY get a couple of weeks of temperatures hovering around 100 degrees with humidity levels to match.  That combination can be punishing.  It can even be dangerous.

Hence my dilemma. Should I cancel this week’s Friday evening meet up of a martial arts group which I run in a local park? The forecast is predicting temperatures in the mid 90s with high levels of humidity.  I think the entire county will spend most of the week under a heat advisory.  Just looking at the numbers one wonders whether its even possible to train in these sorts of conditions.

The short answer to that last question is yes.  Places like Hong Kong and Singapore have much more severe summer heat and they are the home of many of the martial arts communities that I am most interested in.  But that doesn’t mean that training in the summer heat is always fun, or even a good idea for individuals who have not acclimated to it.

I had the opportunity to live in Japan as an undergraduate and experienced a very memorable summer while there.  That was probably my first exposure to training under extreme heat conditions.  I was a member of a small college martial arts club which only had a handful of members.  It was a relaxed, student run, affair. Normally the guys who did judo worked together and the small click of kendo students trained in their own corner of the room.  I would work out with the single karate student as I was studying ITF Taekwondo at the time.

The whole thing was a lot of fun.  But just as the summer heat got miserable, the kendo students decided that it would be great to host the rest of us for some “special training.”  I actually suspect that they were worried that I would leave Japan without getting to experience the country’s most popular martial art.  Kendo had always looked fascinating, so I was happy to train with them, however briefly.

The first thing I learned was how suffocatingly hot all of that gear can be, particularly when you are training in a not sufficiently air conditioned dojo.  The second thing that I learned was just how hard all of that kneeling could be when your legs were spasming with muscle cramps as a result of dehydration.  Which is to say, I Ioved every minute of it.  But I do not want to inflict anything like that on the Friday night training group.


Judo at Ina Middle School. Vintage postcard circa late 1930s. Source: Author’s personal collection.


Advice for Training in the Heat

Late last year I published another short essay on training in extreme weather.  At the time we were concerned with the costs and benefits of working out in the snow.  Ultimately we concluded that there are substantial health benefits to be gained if certain precautions are taken.  So what about training in the summer heat?  Is there any gain to be had from all the pain?  Should we all head out for a run in the heat of the day?

As always, there are certain dangers that one needs to be aware of, and you should never undertake any serious exercise program without consulting your doctor.  That is always good advice, but it turns out to be especially true when discussing physical training in extreme weather as that may stress your heart or lungs. 

So lets start with the bad stuff.  What could possibly go wrong? Quite a bit as it turns out.

Dehydration is probably the most common issue to arise.  One needs to be well hydrated before starting any outdoors activity, and in extreme heat it is important to stop and take regular water breaks as you may already be well on the way to dehydration before you feel thirsty.  Common symptoms of dehydration include muscle cramps (like the ones that I experienced in Japan).  Also note that children are more susceptible to dehydration than adults.  While I am generally all for “traditional training,” I would approach with caution any practice that restricted your access to water while exercising in extreme heat.

More serious is heat exhaustion. Watch out for feelings of lightheadedness, nausea, vomiting, physical weakness, excessive sweating or cold, clammy skin.  During a bout of heat exhaustion one’s internal body temperature may rise as high as 104 degrees.  If you continue to exert yourself beyond this point bad things tend to happen.

The most common of those would be heatstroke.  This is a life and death condition that occurs when an individual’s core body temperature moves above 104 degrees.  The skin may be red and dry from lack of sweat.  Heart beats per minute and respiration rates shoot up as the body seeks to cool itself.  Lastly, confusion, irritability, visual problems and dizziness may be followed by loss of consciousness, organ failure and death.

The Mayo Clinic suggest that anyone exercising in the heat be familiar with the following warning signs:

  • Muscle cramps
  • Nausea or vomiting
  • Weakness
  • Fatigue
  • Headache
  • Excessive sweating
  • Dizziness or lightheadedness
  • Confusion
  • Irritability
  • Low blood pressure
  • Increased heart rate (beyond what one expects during exercise)
  • Visual problems

If you begin to develop any of these symptoms, stop, move to a cool place, get hydrated and let your body temperature return to normal.  Remove any excessive clothing or bulky training gear. Individuals suffering from heat exhaustion will need to seek medical help if their body temperature remains elevated.  Needless to the say, the same goes for anyone with signs of heatstroke.

That is basically everyone’s official list of things to watch for in extreme heat training.  I would like to add a couple of additional items based on my own observations.  To begin with, most of us only experience exercise under these conditions when we are outdoors. Always wear waterproof sunblock whenever you are training outside.  Nothing ends an outdoor exercise program quite as quickly as a bad case of sunburn on the first or second day.

Second, consider all of the things that want to eat you.  In central New York that mostly means mosquitoes and ticks.  I suppose if I was in Florida the list would be different.

Mosquitos are a nuisance that can be taken care of by finding sweat resistant bug spray.  Ticks, however, are a more serious matter.  As carriers of Lyme disease they are becoming a serious public health issue where I live, particularly for individuals who may include hiking or trail running in their workout.  And lets face it, there is nothing more epic than doing your forms after hiking or jogging to the top of a cliff.  Always check for ticks at the end of any instagram worthy adventure, and consider wearing long, breathable, workout pants if you know that you will be hiking in an area where they are common.

With all of that on the table, is there actually any reason to put up with the risks of training in the summer heat when most of us have access to temperature controlled spaces? Absolutely. There is a small body of clinical evidence that suggests individuals who properly acclimatize and train in the heat for short periods of time (typically a couple of weeks) see greater performance gains than athletes doing identical workouts in cool spaces.

The paper that is most often cited in these discussions is a 2010 experiment conducted by Santiago Lorenzo at the University of Oregon.  After carefully observing the baseline performance levels of 20 elite cyclists, 12 were assigned a workout schedule to be conducted in a temperature controlled room set at 100 degrees, while the remaining control group did the exact same workout in a room cooled to a chilly 55 degrees.  At the end of a 10 day training period the performance of the two groups of cyclists was once again observed and measured.  

The results were striking.  The control group showed no improvement, most likely because they were all elite athletes near the top of their game to begin with.  But the group who had worked out in extreme heat saw a 6% performance boost.  Researchers hypothesized that this was a result of increases in their VO2Max (the total amount of oxygen your body can use during an intense effort) and their total blood volumes.  By producing more blood the body was able to continue to cool itself efficiently without robbing the large muscle groups of the oxygen that they needed to function (which is a contributing factor to the cramps discussed above).

As with all good things, moderation is the key.  One must be in excellent shape to carry out this sort of regime while locked in a 100 degree room.  Most of us will be working our way up through the 80s and 90s, slowly acclimating to the rising temperatures, and remembering to pay close attention to the humidity.  High levels of humidity interfere with the body’s ability to dissipate heat through sweat and that increases the likelihood of heat exhaustion or heat stroke.

Yet from an athletic standpoint, the interesting thing is how quickly the body can adapt to these new conditions.  It wasn’t necessary for these athletes to train in the extreme heat for months.  They saw marked improvements in less than two weeks time.


Kendo and Judo as part of life in the Japanese Navy. One imagines that the deck of a warship in the South Pacific would have made for a warm workout. Source: Vintage Postcard. Author’s personal collection.


What is Old is New Again

This brings us back to the Asian martial arts.  Many Chinese teachers insist that year round outdoor training is the key to building up one’s physical stamina and psychological perseverance.  “Eating Bitter” has always involved grueling training in difficult environmental conditions.

Some martial artists in Japan seem to have taken this same basic tendency and refined it to the point of asceticism.  Of course the bushi of old would have trained outdoors as that was where most fighting actually happened.  Being able to mount an effective attack or defense in the heat of the summer, or on a cold winter night, was a very practical thing.

In the hands of Meiji era martial arts reformers, such practices came to be reimagined as a way of sharpening the fighting spirit of the nation’s youth, rather than just their technical skills.  Perhaps the most famous of these efforts originated with Kano Jigoro who, in 1897, established Shochu-Geiko training at the Kodokan.  Traditionally held during the entire month of August, students were expected to engage in long, specially designed, workouts timed to occur during the hottest part of the day.  These were instituted to inure students against environmental distraction while promoting perseverance in the face of adversity.  A similar training regime was also instituted for the coldest days of winter.  

Both the summer and winter training regimes are still part of Kodokan judo today.  From a historical perspective its interesting to note that such ascetic practices attracted the attention of early western authors reporting on the Japanese martial arts with an eye towards explaining the country’s rapid modernization.  For instance, E. J. Harrison devotes a paragraph to these practices in his seminal text, The Fighting Spirit of Japan (1912).  Unfortunately he was more interested in the extremes of cold weather training than heat.  Likewise, the practice is briefly discussed in W. H. Morton Cameron’s 1912, Present Day Impressions of Japan. 

Both of these works were meant to appeal to a general audience, rather than the small community of sportsmen who actually practiced jiujitsu or judo in the West.  Yet that is what makes them so significant. An ethos of spartan self-denial was quickly linked to the Japanese martial arts within the public imagination, and early accounts of Kano’s “summer training” helped to establish that.

Kano’s plans for moral and spiritual education not withstanding, it is interesting how closely Shochu-Geiko resembles elements of modern sports training.  Again, such practices only need to be carried out for a matter of weeks, rather than months, to get the benefits that are available.  And while he probably didn’t have tournament wins in mind when instituting the practice, this type of training likely aided his fighters as they carried out contests in Japan and abroad.   

All of which returns us to my dilemma.  It is vitally important to know one’s own fitness level.  But there is no intrinsic reason to avoid training in extreme heat.  Martial artists always benefit from the ability to work on our skills under challenging conditions.  As such, I believe that the climate should usually be treated as a (carefully deployed) training tool rather than as an obstruction.

I doubt that everyone in my martial arts group is acclimated to the current levels of heat as most of our workouts happen in a well appointed, pleasantly air-conditioned, school.  As such I will be watching the heat index closely and using that number for my final decision.  But I will also be encouraging my students to get used to outdoor exercise as part of their daily practice during the summer months.  Even if you have to go slow and keep the workout short, its another opportunity to come to understand what both you and your art are really capable of.  



If you enjoyed this essay you might also want to read:  Spreading the Gospel of Kung Fu: Print Media and the Popularization of Wing Chun (Part I)