July 7 , 2017 / 17 minutes, 53 seconds

Runners! The Real Reason You Need Yoga – Endurance!

Author: Annette K. Scott

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We, in the yoga world, know (just like you do) that runners need to stretch a bit before and after a run…In fact, I don’t think that there is a yogi out there that hasn’t had a runner friend say some version of, “You do yoga? God…I need to do yoga. I need to stretch. I’m so tight though…I would never make it through a yoga class…” And we also know that knowing something doesn’t always translate into doing something about what you know…So rather than beat you up about the fact that you must stretch if you want to keep running and be able to live in that body without a ton of pain, we created a class just for you!

We are kicking off a running and stretch class Wednesday, July 12th at 6:15am where you can get a mini-stretch in before you run and a little more a stretch after you run. We’ve laid out three simple out and back courses so that you get a short or medium run in AND get some yoga in with other runners…

The whole thing is designed to get you back out the door and into the rest of your day by 7:15 so – no excuses! And while the stretch portion of this class is done in an unheated room, you might want to read on about why, once you’ve gotten past the fear of being mocked for your tight quads and miserably short hamstring, you might want to try a hot yoga class too.


Again you know that you need flexibility but now research finally gives us the real reason for why you need to get on a yoga mat! A regular hot yoga practice can help you increase growth hormone production, muscular hypertrophy, and give a 32%+ boost in endurance. If we put that in fancy runner’s terms, this means that you will  “bonk” later and hit a “softer” wall altogether. So if you are a “serious” runner and really want something that will aid your overall performance, start thinking hot yoga baby!

First things first…Heat is no joke. For the most part, people don’t like to get hot, despite what’s been said before…

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Just look at our massive indoor climate control systems and the pleasantly chilled water fountains that we have most of the places where we work out – but here’s the surprise: research shows that increasing your core temperature for short bursts is not only healthful, it can also dramatically improve performance.

This is true whether it’s done in conjunction with your existing workout or as an entirely separate activity. I’m going to explain how heat acclimation through sauna use (or a hot yoga class like 26&2 or Hot Power) can promote physiological adaptations that result in increased endurance, easier acquisition of muscle mass, and a general increased capacity for stress tolerance. The concept of deliberately acclimating yourself to heat, independent of your usual work out, is known as “hyperthermic conditioning” as coined by Dr. Rhonda Patrick (for transparency and to remain in integrity, lots of this article has been “lifted” from a collection of her articles about heat and cold shock proteins. AND I (Annette) think Dr. Rhonda is my hero – I want to grow up to be smart just like her…).

Here’s a video where she talks about sauna use and how it works to bring you all these crazy benefits. Remember that Kodawari Studios uses infrared heat for all our warm-to-hot yoga just like a sauna!

The fascinating thing is that the positive effects of heat acclimation doesn’t end with helping gain muscle mass – it also has positive effects on the brain, including the growth of new brain cells, improvement in focus, learning and memory, and ameliorating depression and anxiety.

In addition, you’ll learn how modulation of core temperature might even be largely responsible for that delicious “runner’s high” that we all love to access after a (rigorous run or, believe it or not, a hot yoga class) via an interaction between the (GEEK ALERT) dynorphin/beta-endorphin opioid systems.

So, if you didn’t watch the video but do want to know more…here are some the effects of heat acclimation on endurance…If you’ve ever run long distances or exercised for endurance, it’s intuitive that increased body temperature will ultimately induce strain, attenuate your endurance performance, and accelerating exhaustion. What might not be as intuitive is this: acclimating yourself to heat independent of aerobic physical activity through sauna use induces adaptations that reduce the later strain of your primary aerobic activity.

Hyperthermic conditioning improves performance during endurance training activities by causing adaptations, such as improved cardiovascular and thermoregulatory mechanisms (I will explain what these mean) that reduce the negative effects from the stressor that is associated with elevations in core body temperature. This helps optimize your body for subsequent exposures to heat (from metabolic activities) during your next big race or even your next workout.

Just a few of the physiological adaptations that occur are:

  • Improved cardiovascular mechanisms and lower heart rate. 1
  • Lower core body temperature during workload (surprise!)
  • Higher sweat rate and sweat sensitivity as a function of increased thermoregulatory control. 2
  • Increased blood flow to skeletal muscle (known as muscle perfusion) and other tissues.2
  • Reduced rate of glycogen depletion due to improved muscle perfusion. 3
  • Increased red blood cell count (likely via erythropoietin). 4
  • Increased efficiency of oxygen transport to muscles.

Hyperthermic conditioning optimizes blood flow to the heart, skeletal muscles, skin, and other tissues because it increases plasma volume. This leads to endurance enhancements in your next workout or race, when your core body temperature is once again elevated.

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Being heat acclimated enhances endurance by the following mechanisms…

  1. It increases plasma volume and blood flow to the heart (stroke volume).2,5 This results in reduced cardiovascular strain and lowers the heart rate for the same given workload.2 These cardiovascular improvements have been shown to enhance endurance in both highly trained and untrained athletes.2,5, 6
  2. It increases blood flow to the skeletal muscles, keeping them fueled with glucose, esterified fatty acids, and oxygen while removing by-products of the metabolic process such as lactic acid. The increased delivery of nutrients to muscles reduces their dependence on glycogen stores. Endurance athletes often hit a “wall” (or “bonk”) when they have depleted their muscle glycogen stores. Hyperthermic conditioning has been shown to reduce muscle glycogen use by 40%-50% compared to before heat acclimation.3,7 This is presumably due to the increased blood flow to the muscles.3 In addition, lactate accumulation in blood and muscle during exercise is reduced after heat acclimation.5
  3. It improves thermoregulatory control, which operates by activating the sympathetic nervous system and increasing the blood flow to the skin and, thus the sweat rate. This dissipates some of the core body heat. After acclimation, sweating occurs at a lower core temperature and the sweat rate is maintained for a longer period.2

So what sort of gains can you anticipate?

One study demonstrated that a 30-minute sauna session two times a week for three weeks POST-workout increased the time that it took for study participants to run until exhaustion by 32% compared to baseline.4

The 32% increase in running endurance found in this particular study was accompanied by a 7.1% increase in plasma volume and 3.5% increase in red blood cell (RBC) count.4This increased red blood cell count accompanying these performance gains feed right back into those more general mechanisms we talked about earlier, the most obvious of which being: more red blood cells increase oxygen delivery to muscles. It is thought that heat acclimation boosts the RBC count through erythropoietin (EPO) because the body is trying to compensate for the corresponding rise in plasma volume.4

In other words, hyperthermic conditioning through sauna use doesn’t just make you better at dealing with heat; it makes you better, period. I do want to mention that while these gains were made with a small sample size (N=6) some of the later studies that I point out reinforce this conclusion.

The Runner’s High and The Role of Dynorphin

Ever wonder what is responsible for the “runner’s high” or post-exercise highs, in general? You’ve probably heard that it’s due to endorphins, but that’s not the whole story.

Beta-endorphins are endogenous (natural) opioids that are a part of the body’s natural painkiller system, known as the mu opioid system, which block pain messages from spreading from the body to the brain in a process called antinociception. What is lesser known is that the body also produces a peptide known as dynorphin (a “kappa opioid”), which is generally responsible for the sensation of dysphoria. The discomfort experienced during intense exercise, exposure to extreme heat (such as in a sauna), or eating spicy food (capsaicin) is due to the release of dynorphin. The release of dynorphin causes an upregulation and sensitization of mu opioid receptors, which interact with beta-endorphin. 46 This process is what underlies the “runner’s high” and is directly precipitated by the discomfort of physical exercise. Translation: the greater the discomfort experienced during your workout or sauna, the better the endorphin high will be afterward. Now you understand the underlying biological mechanism that explains this.

How is this relevant to hyperthermic conditioning and sauna use?

Heat stress from heat exposure in a dry sauna has been demonstrated to cause a potent increase in beta-endorphin levels, even more than exercise alone.1,15

A study in rats explains this somewhat: dynorphin delivered directly into a part of the hypothalamus in the brains of rats triggers a drop in their body temperature, while blocking dynorphin with an antagonist was shown to prevent this same response. Similarly, mu receptor agonists have been shown to induce increases in body temperature in rats. 47 What this seems to imply is that perhaps, by deliberately manipulating your body temperature you are actually directly engaging the mu (endorphin) and kappa opioid (dynorphin) systems since they clearly play a role in temperature regulation in general.

In Conclusion

To recap and drive the point home: acclimating your body to heat stress by intermittent whole-body hyperthermia via sauna use (“hyperthermic conditioning”) has been shown to:

Enhance endurance by:

  • Increasing nutrient delivery to muscles thereby reducing the depletion of glycogen stores.
  • Reducing heart rate and reducing core temperature during workload.

Increase muscle hypertrophy by preventing protein degradation through the following three means:

  1. Induction of heat shock proteins and a hormetic response (which has also been shown to increase longevity in lower organisms).
  2. Cause a massive release of growth hormone.
  3. Improving insulin sensitivity.

Hyperthermic conditioning also has robust positive effects on the brain:

  • Increases the storage and release of norepinephrine, which improves attention and focus.
  • Increases prolactin, which causes your brain to function faster by enhancing myelination and helps to repair damaged neurons.
  • Increases BDNF, which causes the growth of new brain cells, improves the ability for you to retain new information, and ameliorates certain types of depression and anxiety.
  • Causes a robust increase in dynorphin, which results in your body becoming more sensitive to the ensuing endorphins.

Life is stressful. When you exercise, you are forcing your body to become more resilient to stress (somewhat paradoxically) through stress itself.

Hyperthermic conditioning is a novel and possibly effective tool that can improve your resistance to the sort of stress associated with fitness pursuits as well as some that are not traditionally associated with fitness such as the protective effects of HSPs on various types of stress. That being said, deliberately applied physical stress, whether heat stress or ordinary exercise, is something that requires caution.

You shouldn’t avoid it altogether, but you should use good common sense, not overwhelm yourself, and make sure to know your limits. (NOTE: you should not drink alcohol before or during sauna use as it increases the risk of death). 48 Personal variation probably comes into play when finding your own sweet spot for building thermal tolerance while avoiding over-extending yourself.

Hyperthermic conditioning in general may be worth a closer look as a tool in the toolbox of athletes.  Perhaps it can be used for much more than just relaxation?

But no matter how enthusiastic you might be, remember: 

  • Heat responsibly and with someone else, never alone.
  • Never heat yourself while drunk, and friends don’t let friends sauna/or do super hot yoga drunk.
  • If you are pregnant or have any medical condition, saunas or super hot yoga classes might not be so good for you. Always speak with your doctor before starting this or any regimen involving physical stressors.

And know when you think about how to improve your running, how to get to that high-end performance without adding injury into the mix, you can make it to the mat with us! Click here to find out which of our hot classes can fit into your schedule!

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