Nathaniel Stephenson, Class of 2021
The mere thought of taking a cold shower or jumping into an unheated pool is
unbearable to some. However, many would argue those few minutes of being uncomfortable is
worth the benefits of the pain. Taking a cold shower is similar to running, the first time is never
easy, and you may want to stop half way through, but you know it is good for you and the more
you do it the easier it will get. This article will examine the benefits of cold showers, often
referred to as cold immersion therapy, cold immersion thermogenesis, or cold water immersion
(CWI). The main benefits of CWI talked about will be examining how it is used for recovery as
well as its enhancements on mitochondrial biogenesis.
It is common for professional athletes to use CWI as a way to recover after a hard fought
game or intense training session. CWI allows athletes muscles to recover faster as compared to
taking a hot shower. A 2009 study on eleven male athletes had half of the participants perform a
recovery procedure for 15 minutes after a designated exercise with one group using CWI and
the other given no recovery procedure. The next day the athletes completed the same exercise
and their performance was measured. The researchers noticed that the CWI group resulted in
significant lower muscle soreness ratings as well as “reduced decrements to isometric leg
extension and flexion strength”. The CWI also allowed the runners to return to their baseline
sprint times. While there are beneficial results from CWI, this study did not compare CWI to
something more typical, such as a hot shower. However, other studies have compared CWI to
something like a hot shower. A study on 41 highly trained male athletes compared the
effectiveness of different types of post-exercise recovery techniques and their effect on maximal
strength, power, and post-exercise inflammatory response. The results showcased that those
who were immersed in cold water and 96 degree Fahrenheit water had a significant improvement in a maximal
isometric voluntary contraction (MVC), a standardized test for measuring muscle strength and in
performance during a maximal 30 second rowing test (P30s). However, those who were given a
cold immersion recovery saw a blunt in the total number of leukocytes after 1 hour and the
amount of creatine kinase (CK) found in their blood after 24 hours. CK is a test used to detect
inflammation of the muscles or muscle damage while leukocytes are inflammatory cells that are
meant to identify the presence of inflammatory diseases. Inflation is meant to fight off foregin
invaders, heal injuries, and mop up debris, but too much inflammation means your body is on
high alert all the time leading to lasting damage. For example when inflammatory cells hang
around for too long, especially in the blood vessels, they can promote the buildup of plaque and
cause clotting. This study suggests that CWI seems to be more effective than the alternative
post-exercise recovery methods due to its greatest restriction of the inflammatory process after
high intensity contraction or muscle damage. In summary CWI is able to aid in muscle recovery
through different facets. CWI allows for a lower tissue temperature which subsequently affects
changes in blood flow, cell swelling and cell metabolism. After an intense exercise, cells
typically demand repair structural damage and replace energy stores. Cooling allows for a
reduction in metabolic stress experienced by the cells. Additionally, CWI is able to cause
reflexive vasoconstriction (the narrowing in blood vessels reducing the amount of blood flow).
Reducing blood flow allows for a decreased risk of muscle fibre edema (swelling), localized
pain, functional ability, and negative effects caused by inflammation.
Where the more interesting benefits of CWI begin is in the ability for this post-exercise
routine to increase mitochondrial biogenesis. Mitochondrial biogenesis is the process by which
cells produce new mitochondria. Under certain conditions such as fasting or exercise, cells will
adjust their metabolic process to maintain the need of cellular energy. When cells need to
upregulate their capacity to make more ATP (cellular energy) they go through mitochondrial
biogenesis to produce more mitochondria. A well functioning system of mitochondrial is thought
to be important for having a long life-span because it slows down the cascade of damage
caused by mitochondrial dysfunction, one of the nine hallmarks of aging. As you age you begin
to see a decline in mitochondrial biogenesis, mitochondrial mass, and a decline of functioning
mitochondrial especially in high-energy demanding tissues such as the heart, lungs, and brain.
Mitochondrial biogenesis can be affected by everyday situations such as exercise, caloric
restrictions (diets or fasting), low temperature, cell division, cell renewal, cell differentiation, and
oxidative stress (an imbalance between free radicals and antioxidants in your body).
Many of the papers referenced will discuss peroxisome proliferator activated-receptor γ
coactivator-1 α (PGC-1α), which is considered to be the “master regulator” of mitochondrial
biogenesis. While there are additional transcription coactivators that play a part in mitochondrial
biogenesis, PGC-1α, is primarily associated with mitochondrial biogenesis in contents of the
energy demanded by the cell. A recent test on 40 mice concluded that exercise and CWI
promoted increased expression of mitochondrial biogenesis-related genes in the soleus muscle
and more importantly that only cold exposure caused a significant effect on the PGC-1α,
protein expression. Testing on mice is typical in early stages of research in a topic, but there
have been more recent experiments performed on humans. What is useful about testing on
humans is that you are able to immerse one part of the body and leave the other part out, to be
used as a control group. This idea was highlighted in an experiment done by the American
College of Sports Medicine where researchers had 9 healthy males perform an exercise
protocol and following the exercise had each male immerse one leg in 50 degrees fahrenheit
water for 15 minutes with the other leg resting outside the cold water. After taking muscle
biopsies the researchers confirmed that CWI resulted in PGC1α mRNA to be 9 times higher.
Higher amounts of mRNA typically signals an increased production of the protein being created.
Another study in the European Journal of Applied Physiology found similar results as the
above mentioned experiment. The study found that after having the participants complete and
intermittent running protocol before undergoing CWI at 46 degrees fahrenheit for 10 minutes.
The test found that after exercise there was a 3.4-fold increase in PGC-1α, without CWI, but in
the presence of cold water there was nearly a 6-fold increase. After this test was concluded the
researchers performed an additional experiment to see how PGC-1α levels would change
without any exercise. They found that without any exercise and only CWI that PGC-1α, levels
increased 1.3 fold. While this is not as significant of an increase compared to the results
post-exercise this is still an improvement nonetheless.
While all these benefits sound incredible to most people, many of you will be wondering
“How do I convince myself to start taking cold showers?”. There are different ways you can start
taking cold showers. One possible way is to start with lukewarm water and every minute slowly
turn the knob until you are at the coldest part. This is typically the easiest method for most
people, as your body will naturally get used to change in temperature. Additionally, you can start
from the coldest possible temperature and slowly make your way up to your ideal temperature.
However, these methods only allow for a few minutes, at best, of cold water immersion. Ideally,
you should try to have cold water running on your body the entire time. For those of you who are
daring and would like the best results you can take a cold bath so your entire body is fully
immersed in cold water.
This is not to say that taking hot showers does not have its own benefits. Hot showers
are known for relieving muscle tension, lowering blood pressure, improving blood circulation,
and being able to reduce cold/flu symptoms. However, not only can cold showers offer a
plethora of health benefits, but they can also provide a huge burst of energy as well as a feeling
that you are able to conquer anything. Taking a cold shower is not meant to be easy, but it's
something everyone should consider if they are trying to improve their health and longevity.
unbearable to some. However, many would argue those few minutes of being uncomfortable is
worth the benefits of the pain. Taking a cold shower is similar to running, the first time is never
easy, and you may want to stop half way through, but you know it is good for you and the more
you do it the easier it will get. This article will examine the benefits of cold showers, often
referred to as cold immersion therapy, cold immersion thermogenesis, or cold water immersion
(CWI). The main benefits of CWI talked about will be examining how it is used for recovery as
well as its enhancements on mitochondrial biogenesis.
It is common for professional athletes to use CWI as a way to recover after a hard fought
game or intense training session. CWI allows athletes muscles to recover faster as compared to
taking a hot shower. A 2009 study on eleven male athletes had half of the participants perform a
recovery procedure for 15 minutes after a designated exercise with one group using CWI and
the other given no recovery procedure. The next day the athletes completed the same exercise
and their performance was measured. The researchers noticed that the CWI group resulted in
significant lower muscle soreness ratings as well as “reduced decrements to isometric leg
extension and flexion strength”. The CWI also allowed the runners to return to their baseline
sprint times. While there are beneficial results from CWI, this study did not compare CWI to
something more typical, such as a hot shower. However, other studies have compared CWI to
something like a hot shower. A study on 41 highly trained male athletes compared the
effectiveness of different types of post-exercise recovery techniques and their effect on maximal
strength, power, and post-exercise inflammatory response. The results showcased that those
who were immersed in cold water and 96 degree Fahrenheit water had a significant improvement in a maximal
isometric voluntary contraction (MVC), a standardized test for measuring muscle strength and in
performance during a maximal 30 second rowing test (P30s). However, those who were given a
cold immersion recovery saw a blunt in the total number of leukocytes after 1 hour and the
amount of creatine kinase (CK) found in their blood after 24 hours. CK is a test used to detect
inflammation of the muscles or muscle damage while leukocytes are inflammatory cells that are
meant to identify the presence of inflammatory diseases. Inflation is meant to fight off foregin
invaders, heal injuries, and mop up debris, but too much inflammation means your body is on
high alert all the time leading to lasting damage. For example when inflammatory cells hang
around for too long, especially in the blood vessels, they can promote the buildup of plaque and
cause clotting. This study suggests that CWI seems to be more effective than the alternative
post-exercise recovery methods due to its greatest restriction of the inflammatory process after
high intensity contraction or muscle damage. In summary CWI is able to aid in muscle recovery
through different facets. CWI allows for a lower tissue temperature which subsequently affects
changes in blood flow, cell swelling and cell metabolism. After an intense exercise, cells
typically demand repair structural damage and replace energy stores. Cooling allows for a
reduction in metabolic stress experienced by the cells. Additionally, CWI is able to cause
reflexive vasoconstriction (the narrowing in blood vessels reducing the amount of blood flow).
Reducing blood flow allows for a decreased risk of muscle fibre edema (swelling), localized
pain, functional ability, and negative effects caused by inflammation.
Where the more interesting benefits of CWI begin is in the ability for this post-exercise
routine to increase mitochondrial biogenesis. Mitochondrial biogenesis is the process by which
cells produce new mitochondria. Under certain conditions such as fasting or exercise, cells will
adjust their metabolic process to maintain the need of cellular energy. When cells need to
upregulate their capacity to make more ATP (cellular energy) they go through mitochondrial
biogenesis to produce more mitochondria. A well functioning system of mitochondrial is thought
to be important for having a long life-span because it slows down the cascade of damage
caused by mitochondrial dysfunction, one of the nine hallmarks of aging. As you age you begin
to see a decline in mitochondrial biogenesis, mitochondrial mass, and a decline of functioning
mitochondrial especially in high-energy demanding tissues such as the heart, lungs, and brain.
Mitochondrial biogenesis can be affected by everyday situations such as exercise, caloric
restrictions (diets or fasting), low temperature, cell division, cell renewal, cell differentiation, and
oxidative stress (an imbalance between free radicals and antioxidants in your body).
Many of the papers referenced will discuss peroxisome proliferator activated-receptor γ
coactivator-1 α (PGC-1α), which is considered to be the “master regulator” of mitochondrial
biogenesis. While there are additional transcription coactivators that play a part in mitochondrial
biogenesis, PGC-1α, is primarily associated with mitochondrial biogenesis in contents of the
energy demanded by the cell. A recent test on 40 mice concluded that exercise and CWI
promoted increased expression of mitochondrial biogenesis-related genes in the soleus muscle
and more importantly that only cold exposure caused a significant effect on the PGC-1α,
protein expression. Testing on mice is typical in early stages of research in a topic, but there
have been more recent experiments performed on humans. What is useful about testing on
humans is that you are able to immerse one part of the body and leave the other part out, to be
used as a control group. This idea was highlighted in an experiment done by the American
College of Sports Medicine where researchers had 9 healthy males perform an exercise
protocol and following the exercise had each male immerse one leg in 50 degrees fahrenheit
water for 15 minutes with the other leg resting outside the cold water. After taking muscle
biopsies the researchers confirmed that CWI resulted in PGC1α mRNA to be 9 times higher.
Higher amounts of mRNA typically signals an increased production of the protein being created.
Another study in the European Journal of Applied Physiology found similar results as the
above mentioned experiment. The study found that after having the participants complete and
intermittent running protocol before undergoing CWI at 46 degrees fahrenheit for 10 minutes.
The test found that after exercise there was a 3.4-fold increase in PGC-1α, without CWI, but in
the presence of cold water there was nearly a 6-fold increase. After this test was concluded the
researchers performed an additional experiment to see how PGC-1α levels would change
without any exercise. They found that without any exercise and only CWI that PGC-1α, levels
increased 1.3 fold. While this is not as significant of an increase compared to the results
post-exercise this is still an improvement nonetheless.
While all these benefits sound incredible to most people, many of you will be wondering
“How do I convince myself to start taking cold showers?”. There are different ways you can start
taking cold showers. One possible way is to start with lukewarm water and every minute slowly
turn the knob until you are at the coldest part. This is typically the easiest method for most
people, as your body will naturally get used to change in temperature. Additionally, you can start
from the coldest possible temperature and slowly make your way up to your ideal temperature.
However, these methods only allow for a few minutes, at best, of cold water immersion. Ideally,
you should try to have cold water running on your body the entire time. For those of you who are
daring and would like the best results you can take a cold bath so your entire body is fully
immersed in cold water.
This is not to say that taking hot showers does not have its own benefits. Hot showers
are known for relieving muscle tension, lowering blood pressure, improving blood circulation,
and being able to reduce cold/flu symptoms. However, not only can cold showers offer a
plethora of health benefits, but they can also provide a huge burst of energy as well as a feeling
that you are able to conquer anything. Taking a cold shower is not meant to be easy, but it's
something everyone should consider if they are trying to improve their health and longevity.
References:
Ihsan, M., Watson, G., Choo, H. C., Lewandowski, P., Papazzo, A., Cameron-Smith, D., & Abbiss, C. R. (2014). Postexercise Muscle Cooling Enhances Gene Expression of PGC-1α. Medicine & Science in Sports & Exercise, 46(10), 1900-1907. doi:10.1249/mss.0000000000000308
Ingram, J., Dawson, B., Goodman, C., Wallman, K., & Beilby, J. (2009). Effect of water immersion methods on post-exercise recovery from simulated team sport exercise. Journal of Science and Medicine in Sport, 12(3), 417-421. doi:10.1016/j.jsams.2007.12.011
Joo, C. H., Allan, R., Drust, B., Close, G. L., Jeong, T. S., Bartlett, J. D., . . . Gregson, W. (2016). Passive and post-exercise cold-water immersion augments PGC-1α and VEGF expression in human skeletal muscle. European Journal of Applied Physiology, 116(11-12), 2315-2326. doi:10.1007/s00421-016-3480-1
Jornayvaz, F. R., & Shulman, G. I. (2010). Regulation of mitochondrial biogenesis. Essays in Biochemistry, 47, 69-84. doi:10.1042/bse0470069
Pournot, H., Bieuzen, F., Duffield, R., Lepretre, P., Cozzolino, C., & Hausswirth, C. (2010). Short term effects of various water immersions on recovery from exhaustive intermittent exercise. European Journal of Applied Physiology, 111(7), 1287-1295. doi:10.1007/s00421-010-1754-6
White, G. E., & Wells, G. D. (2013). Cold-water immersion and other forms of cryotherapy: Physiological changes potentially affecting recovery from high-intensity exercise. Extreme Physiology & Medicine, 2(1). doi:10.1186/2046-7648-2-26
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