Tuesday, May 4, 2010

Loving the heat

The warm weather brings a hot and sweaty practice… I’ve missed it!

As I mentioned in this post a few months back, I found my body temperature rises about 2 degrees during my practice (this was not the most accurate measurement and I think it's probably higher than that).

But my question is: what is the effect of generating this daily fever as a result of practice (or any other sweat-inducing exercise for that matter)?

Treatment for certain tumors includes the use of regional hyperthermia (temperatures up to 104-109 degrees Fahrenheit). The high temperature sensitizes the tumor to radiation and/or chemotherapy. Exercise can’t raise our body temperatures that high, but what might be the effect of the more mild increases in body temperature that exercise creates?

I couldn’t find an answer to this specific question, but I did find this paper, which discusses how “mild hyperthermia” enhances immune system functioning and may provide long-term protection from tumor growth. They write:

“There has long been appreciation in this field of the potential similarity between exogenously induced hyperthermia used in the clinic and natural hyperthermic states which occur during fever. Because of the close association between fever, inflammation and immune cell activation during infection, several investigators have speculated that there could be significant effects of elevated (fever-range) temperatures on enhanced anti-tumor immunity.”

I wonder how high we can get our body temperatures during practice... (trying to think of a good way to measure this?)

Might yogis (and other athletes) who create and sustain and daily “fever” have stronger immune function as a result? And might this help fight infections and cancers over a lifetime? 


  1. i say.. bring a thermometer to practice. take your temp for a week. maybe after dropbacks.. before closing.. and go from there. i doubt anyone would care if you did a little 'research' on the mat. i'm interested to know..

    i definitely think my immune system is functioning stronger after this practice of yoga. i worked as a nanny for a long time with a kid who always had colds and two doctors as parents and i seemed to come out of that unscathed. <3

  2. Hi Christina! I'm wondering if this is why saunas are supposed to be so good for you.

    I'm loving the heat and all the sweating too!

    I have a question about this part:

    "Because of the close association between fever, inflammation and immune cell activation during infection, several investigators have speculated that there could be significant effects of elevated (fever-range) temperatures on enhanced anti-tumor immunity.”

    I thought inflammation was generally bad. Does this mean it's sometimes a good thing? Does exercise-induced heat cause inflammation?

  3. so interesting! perhaps this could be related to the immune-system boost babies get when they are constantly sick with coughs and colds from daycare (and have mild fevers)? I read that the germ exposure in daycare reduces childhood leukemia rates (as well as asthma and other auto-immune diseases).

  4. Yeah Amanda, I should do this! I just need to find the right thermometer to measure core body temperature.

    Hey Kim, yeah that would make sense! Babies need to build up their immune systems so it's probably good for them to be exposed to lots of germs when they're young... strengthen that immune system now! One explanation for why so many kids have allergies and asthma today is because we are keeping them too clean.

    Leslie that's a really good question about exercise and inflammation. You are right that inflammation is generally thought of as bad (risk factor for heart disease, for example), and one reason exercise is so good for you is because it reduces inflammation in the long-run.

    That quote from the paper is talking about fevers that result from inflammation from underlying infections and/or cancers. So that kind of fever is different from the exercise-induced "fever" where we are generating heat in a healthy body without infection/cancer-induced inflammation.

    But you raise a good question as to whether in that 1-2 hour period of exercise and heat-generation leads to higher levels of inflammation... I wouldn't be surprised if it does, but then leads to lower levels over time. This goes back to the hormesis idea (http://prescribingyoga.blogspot.com/2010/02/hormesis.html) where low levels of a toxin given daily makes the body immune to high doses.

  5. Christina Palmer
    for the future
    Surgeon General of the United States
    please yes

  6. I have a great in ear thermometer that takes your temp in five seconds.

  7. haha PERFECT! if you bring it in we can start collecting some data!

  8. We could just turn the sign-in sheet into a data sheet, and have the thermometer next to the water bottles. Sign in, practice, measure temp after drop backs, savasana, jot down temp on way out. You'd get plenty of data in no time.

    Speaking of immune systems, am currently waiting for mine to kick it into high gear and rid this stubborn cold out of me... I miss the shala! And all of you! Though it might be my shoulder's way of finally getting me to give it a rest... I hope to see you all soon when I'm not in danger of getting you all sick! :)