Cortisol

If you are reading this article there is a good chance it is because you have entered the upcoming Pittsburgh Marathon, or any marathon for that matter, and are looking for ways to feel that you have reached your peak level for performance. Before I delve into where cryotherapy fits into the big picture lets take a quick second to talk about some basic training principles, but not too much because periodization is not the focus of this post. As you prepare, hopefully you have slowly increased to the total volume per week of mileage. However, as you have probably noticed, as the workout intensity increases so does the amount of time it takes to recover between runs. Despite even putting a well-planned taper into your program, there may be an imbalance of stress from running to recovery. Optimal performance depends greatly on not only your training but your recovery as well, which is what I would like to focus on. According to the head coach of cross-country at the University of Houston, Steve Magness, there are both physiological and psychological aspects of recovery.  For the purpose of this article we are going to talk about stress response, physical damage, neural/central fatigue and emotional/mental readiness and how cryotherapy can possibly help with recovery to each one of these components. 

There are many aspects to stress response but what I would like to focus on is cortisol and its impact on the body. To keep things simple for the purpose of this article, here is what you need to know about cortisol; it allows your body to mobilize and metabolize energy at a faster rate. If you want to learn more read Why Zebras Don’t Get Ulcers, Dr. Sapolsky does a fabulous job going into detail.  However, a problem comes when cortisol levels elevate in your body when the stress is no longer being applied. As a runner, it is during these times without the stress of running that you are looking for your body to recover. However when cortisol is high, priority shifts from the aspects of recovery to the function or cortisol in the body. A good way to look at this is comparing your cortisol to testosterone ratio.  If we take the findings of a Swiss study on cyclists, it was found that the ratio of testosterone/cortisol or IGF-1/cortisol may be a useful marker of the body being over trained and not recovered. (Hug et al. 2003).  It is important that your body is in an anabolic state, testosterone positive ratio, when you are not training so that your body can recovery.  Now shifting to how cryotherapy can aid in managing cortisol levels post-workout in the body. In a 12-week study, it was found that in as short as 4 weeks there was a reduction in basal cortisol levels after cyrotherapy sessions (Leppaluoto et al. 2008). From these results it can be argued that by keeping cortisol levels lower, the body is able to be in a better state for recovery between training sessions. 


Sympathetic Vs. ParaSympathetic

We have just discussed the role that cortisol plays in inhibiting the recovery process of our body. But what is it that causes our body to release cortisol to begin with? You may be able to recall from biology class the autonomic nervous system and the fight or flight response, which is what your body goes through when presented with a stressful situation. At this point your body has switched from its parasympathetic nervous system, the laid back relaxed system, to it sympathetic nervous system aka fight or flight. It is this switch that gets you geared up to handle what ever it is you are about to handle. Here is the thing though; your body does not know the difference between running a marathon, financial stress, or even life threatening situations, it just knows it is time to get you prepared to physiologically handle this disturbance. This activation of your sympatric nervous system is what is responsible for firing up your adrenal gland and release cortisol. As was brought up earlier, cortisol is good during specific times but too much leads to problems. But how do we know that our sympathetic nervous system is switching to the parasympathetic nervous system?  The last thing you need if you’re training for a marathon is to run straight into the effects of overtraining. Luckily, we can see which state our body is in by using heart rate variability (HRV). HRV measures the variability between R waves (the peaks on the graph) on an EKG reading. When your body is in the sympathetic state there is very little variability between heartbeats. Conversely, a large variability indicates a more parasympathetic dominant state, which is where you want to be during recovery. So how does cryotherapy fit into this picture? Hausswirth and colleagues (2013) looked into whether or not partial body cryotherapy (PBC) or whole body cryotherapy (WBC) more effectively activated parasympathic nervous response. From their testing it was not only found that both means of therapy induce a parasympathic tone verified by HRV data but also that WBC induced a larger stimulation of the autonomic nervous system. From this result and what we learned in the previous paragraph, not only can WBC help reduce resting cortisol levels, it can also induce a sympathetic tone to create a better environment for recovery.


Oxygen Flow

The previous two paragraphs cover the stress response in the body. Now lets talk about the physical toll that running takes on the muscle fibers, tendons, ligaments and bones in your body. Exercise leads to micro traumas to the body. The way we get stronger is during the time of recovery, when our body works to repair those micro traumas. This is why it is important to allow your body to reach a state that allows it to recovery rather than keeping it in a constant fight or flight mode. Again, keeping things simple, a key factor to healing these micro traumas is blood flow, this allows both oxygen and nutrients to be delivered to the site or repair. Imagine your micro traumas are all the potholes in Pittsburgh and the blood and oxygen is the city actually sending out people to repair them. Clearly we are going to need a lot of trucks sent out to do the job. Well, if we can increase blood flow, then more oxygenated blood and nutrients can be in circulation. The effects of WBC on recovery was studied in 11 endurance runners and tested by a pretest to exhaustion followed by either the WBC session or placebo before a retest to exhaustion. It was found that the group with the WBC recovery session out performed the placebo group on the retest (Kruger et. al 2015). Kruger suggests that the reason for this increase in performance was due to higher oxygenation to working muscles as a result of the WBC recovery sessions. 


Mental State & Norepinephrine

Finally an aspect that may get often overlooked when thinking about recovery is one’s mental state. Simply put, if you don’t feel good then you aren’t going to be performing at your best. Often, symptoms of depressed mood can be associated with overtraining but even before reaching an overtrained state one can find it difficult to keep up with a training regimen as the workload increases. Along with cortisol, which we already discussed, another hormone that plays a big role in the body’s stress response is norepinephrine.  Norepinephrine is released from the adrenal cortex during times of stress to help ready the body to deal with the present situation. When norepinephrine acts as a neurotransmitter, it is related to alertness, sleeping, emotions and more. In a classic study done by Janowsky, Davis and colleagues in 1972, they were able to suppress the level of norepinephrine in the body through the administration of cholinomimetic agents. The result in those who received the treatment showed signs of decreased mood, lack of energy and general symptoms of depression. From this it was concluded that proper levels of norepinephrine are related to positive moods. As stated earlier, due to the activation of the sympathetic nervous system, a release of norepinephrine can help elevate an athlete’s mood as the ride the rollercoaster of intensive training.  Studies have shown that a session of WBC correlates with a two- to three-fold acute increase in the release of norepinephrine, a level of release that remains consistent over multiple exposures.

In conclusion, four areas of recovery have been presented along with how they all can be supported and enhanced by the use of whole body cryotherapy treatments. As important as it is to train hard its just as important to pair that training with the proper recovery. Avoiding this asymmetry is the best way to prepare for any major event. Just as people will supplement their workouts with vitamins for energy, better clothing for staying cool, proper nutrition to refuel, it would only make sense to supplement ones recovery with cryotherapy for optimal performance.