Cold Therapy - Is It Worth It?

There has been a lot of discussion regarding cold therapy, including cold water immersion and cold showers, on podcasts, news articles, and TV. Because of this, I recently had a 54-year-old patient, Stella, ask if adding cold therapy to her home program would be helpful. She has been dealing with chronic low back pain and decided to participate in pelvic floor physical therapy after reading that it can be a helpful, missing piece to low back pain. Stella has been working hard to change some of her current habits, including sleep schedule, nutrition, and exercise to better address her symptoms. 

Despite the amount of discussion about cold therapy, there is still very limited research on this topic meaning we do not understand the full extent of benefits, or lack of, for this treatment. There is some basic knowledge regarding our body’s response to cold. For example, one change that occurs is called vasoconstriction, meaning the blood vessels narrow to bring more blood back to our core for vital organs and away from the periphery of our body, such as hands and feet.1 Once we reach a certain level of cold, our body begins to shiver to increase heat and try to warm us up. When our body shivers, it uses more energy because the muscles are being used. Our body is also able to increase heat produced when exposed to cold by using brown adipose (fat) tissue (BAT). BAT has more mitochondria (aka is more energy producing) than white adipose tissue (white fat). This means that when we’re exposed to cold, BAT uses triglycerides (fat) to create heat. White fat can also be turned into BAT the more often we use BAT. 1

Cold water immersion (CWI) has a reduction and transformation of body fat which could be protective against diabetes and cardiovascular disease.1 Cold-adapted swimmers have a protective effect against cardiovascular risk with regular cold-water immersion (CWI). However, keep in mind that doing CWI increases the work of the heart and can cause elevated blood pressure, which is why it is recommended to discuss cold therapy with your medical provider prior to implementing it.1 

Also, CWI can increase tolerance to bodily stress, which can have a positive immune system effect.1 Some emerging research suggests a positive impact on mental health including relieving depression symptoms. CWI does increase a chemical called norepinephrine meaning that it may assist with pain reduction.1

A recent systematic review looked at the impact of cold water on heart rate variability (HRV).2 Heart rate variability is the number of heart beats per minute and is the normal fluctuation in time between heartbeats during different states like relaxed versus anxious or resting versus active. Our heart rate is controlled by the autonomic nervous system meaning “automatic”. Our autonomic nervous system is further divided into the parasympathetic and sympathetic nervous system. The parasympathetic nervous system is part of the rest and digest, or calm aspect and the sympathetic nervous system is part of the fight, flight, freeze when we are anxious, stressed, or over excited. These two parts are meant to balance each other. When we are in fight, flight, freeze mode, our heart rate increases and when we are in rest, digest mode our heart rate decreases. High heart rate variability essentially shows that our body is resilient enough to adapt from one state to another. Low heart rate variability shows that’s our body is less able to adjust to challenges and switch between nervous system states.2 

When diving in cold water, our body pushes blood back to our trunk instead of our limbs causing an increased heart rate and increased work our heart must perform.2 Shortly afterwards, our heart rate decreases. This response can be trained the more we practice. When our blood is pushed back towards our trunk, our sympathetic nervous system is activated first and then our parasympathetic nervous system (PNS) is activated afterwards which causes the lower heart rate. According to this systematic review, “cold seems to strengthen the PNS responses of diving”. However, the “knowledge is limited” and more research is needed to determine the full effects of cold-water diving on heart rate variability.2 

Another study looked at the effect of taking a hot to cold shower, for 30, 60, or 90 seconds, over 30 consecutive days and found a 29% decrease in sickness absence from work compared to those that did not incorporate cold in their showers.3 Interestingly, regular physical activity had a 35% reduction of sickness absence. When physical activity is combined with the hot to cold shower, there was a 54% reduction of sickness absence compared to people who did neither. Quality of life showed a slight beneficial effect in the short term of 30 days but did not have continued benefit at 90 days. Those that participated in hot to cold showers did have a “perceived” increase in energy levels.3

In summary, cold therapy, including cold water immersion, diving, and cold showers could have beneficial effects including increasing our brown adipose tissue, decreasing cardiovascular risk, improving the body’s resiliency to stress both physically and mentally as shown by heart rate variability, possibly reducing sickness absence, and increasing perceived energy levels. However, keep in mind that you should discuss the possible negative effects of cold-water immersion with your medical provider, especially the initial increase in heart rate and breathing which would be problematic for someone with cardiovascular concerns. Also, the overall research on cold therapy is limited meaning the benefits cannot be fully supported at this time. There are other more important pillars of health that have substantially more research including adequate sleep quality and volume, daily physical activity and exercise, ample hydration, purposeful nutrition, and daily mindfulness/meditation that should be implemented and mastered before adding cold therapy in my opinion. Once these other important habits are implemented, adding another adjunct like cold therapy could be helpful to reap additional benefits. 

If you have questions or concerns about addressing your chronic pain or other pelvic health concerns, please reach out to your local pelvic floor therapist who will assess and develop an individualized treatment plan to best address your concerns.

Written by Jordan Schmidt, PT, DPT

References

1. Esperland, D., de Weerd, L., & Mercer, J. B. (2022). Health effects of voluntary exposure to cold water - a continuing subject of debate. International journal of circumpolar health, 81(1), 2111789. https://doi.org/10.1080/22423982.2022.2111789
2. Richard Viking Lundell & Tommi Ojanen (2023) A systematic review of HRV during diving in very cold water, International Journal of Circumpolar Health, 82:1, 2203369, DOI: 10.1080/22423982.2023.2203369
3. Buijze, G. A., Sierevelt, I. N., van der Heijden, B. C., Dijkgraaf, M. G., & Frings-Dresen, M. H. (2016). The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PloS one, 11(9), e0161749. https://doi.org/10.1371/journal.pone.0161749