Photobiomodulation (PBMT) vs. Cryotherapy?
Recovery & Regeneration Solutions
Perhaps you have heard of the recent trend in Recovery Solutions a spinoff from Regenerative Medicine. Many of these Recovery Solutions make claims that they will lower oxidative stress, improve recovery (measured as the ability to exercise longer and/or exercise with higher force output).
One of these is Whole Body Cryotherapy (WBC), the technology that is used in cryosaunas, which briefly exposes the body to air temperatures below 100C for 2- 3 minutes. Cryosaunas are becoming popular in fitness and wellness centers. Here we compare the technology and the evidence regarding WBC compared to Photobiomodulation Therapy (PBMT).
Recovery Solutions are important because high-intensity exercises are associated with the following: muscle injury, oxidative stress, inflammation, and fatigue. These all contribute to decreased performance.
Light Lounge is committed to evidence-based research on side effects and efficacy of any intervention that claims performance and recovery enhancement.
PBMT & Cryotherapy
A randomly controlled, single-blind study placed 40 participants into 5 groups:
1. Placebo Group
2. PBMT Group - PBMT applied to the biceps muscle belly
3. Cryotherapy Group (CG) - Ice bags applied to the biceps muscle belly
4. Cryotherapy/PBMT Group (CPG) - Cryotherapy first then PBMT
5. PBMT/Cryotherapy Group (PCG) - PBMT first then Cryotherapy
Participants performed Maximal Voluntary Contractions (MVCs). After a 2 min rest they performed 10 biceps curls with the highest strength possible to resist an isokinetic dynamometer (a machine that creates resistance at a constant speed). 30 seconds after the curls ended, another MVC was performed to measure how much the exercise had compromised the muscle. Additionally, each group performed an MVC 24, 48, and 72 hours after the exercise. Blood samples were also collected exactly 5 min, 60 min, 24 h, 48 h, and 72 h after the end of the exercise intervention.
There were no differences in the following measures before the exercise intervention between the groups:
- MVCs
- Oxidative damage to muscle and lipids
- Blood Creatine Kinase (CK) - a biomarker for muscle damage
- Delayed onset muscle soreness (DOMS) - this is thought to delay recovery
- TBARS - biomarkers for lipid damage
The results of the treatment groups vs. placebo group after the exercise intervention were as follow:
- The PBMT, PCG, CPG groups all had higher MVCs, lower lipid damage, and lower DOMS ratings 60 min, 24 h, 48 h, and 72 h after the exercise intervention
- The PBMT group had decreased in CK across all post-intervention time points. The PCG and CPG were delayed at 48 h and 72 h
- The CG group demonstrated a decrease in lipid damage biomarkers, the only demonstrated difference between CG and placebo
The few benefits that cryotherapy had were heightened when PBMT was also applied. However, cryotherapy had no effect on MVC results compared to placebo. The PBMT group had an increased MVC value. Cryotherapy had no protection against muscle damage (CK markers) whereas PBMT protected the muscle from damage better than any other treatment. In fact applying cryotherapy in conjunction with PBMT decreased the beneficial effects of PBMT (regardless of the order).
Not All Cryotherapies are the Same
The term Cryotherapy is used for both cold-water immersion, ice-pack application, and liquid nitrogen based air cooling (whole body chamber or partial body Cryosauna). A meta-analysis study examined 10 WBC controlled or crossover trials. In all the trials the authors found that due to the poor thermal conductivity of air, the muscle and body core cooling was not as effective as old fashioned techniques such as cold-water immersion and local ice-pack application. In a few studies they found that the participants receiving WBC had subjective improvements in muscle soreness and recovery, but this did not translate into increased performance. Additionally, the authors found no evidence to suggest that WBC helps to decrease muscle damage. There is little evidence to suggest that WBC can slightly decrease oxidative stress (as measured by lipid peroxidation). Counterproductively, however, WBC did lower anti-oxidant enzyme levels.
FDA Warning
The FDA has issued a warning about Whole Body Cryotherapy. In this government warning the following issues are highlighted:
- Asphyxiation - Liquid Nitrogen, turning into a gas can cause death
- Risk of frostbite, burns, and eye injury from the extremely low temperatures
- Very little evidence about its safety
Few Randomized Control Trials & No Double-Blind Studies
One study looked at 22 randomized controlled trials of Cryotherapy vs. Placebo, none of the trials included WBC. The authors found that most of the studies that can be found have poor or incomplete analyses. They noted that Cryotherapy (cold water submersion in this case) was better at reducing swelling than heat therapy, and long-term effects (anything greater than 1 week) are unknown. The authors claimed that there is little evidence to suggest that Cryotherapy can help an athlete return to training more quickly than doing nothing.
Although it is possible to undertake randomized control trials, it is very difficult if not impossible to complete these trials blindly. Because the participant will always feel the cold temperatures. See our quality research studies discussion.
Ice Bath, Recreational Athletes, & Running
A study looked at 20 recreational males who completed a 40 min run at -10% grade and at 60% of VO2max to induce muscle damage. Downhill running is ideal because it induces muscle damage and inflammatory response. 10 men were immersed in a 5� C bath for 20 min, the other 10 men were control (not a single nor a double-blind study). The authors found no difference after the intervention between the groups in the following:
- Soreness (using the Visual Analog Scale)
- Knee extensor MVC
- Inflammatory biomarkers (chemokine ligand 2 - CCL2)
The authors concluded that their "results do not support the use of cryotherapy during recovery" because there were no differences between groups.
WBC, Physical Therapy, & Rheumatoid Arthritis (RA)
A group of researchers enrolled 44 female RA patients. 25 were treated with WBC and 19 were treated with traditional physical therapy methods, such as ultrasound therapy and electrotherapy. The researchers found that WBC was just as effective as traditional physical therapy methods to relieve pain, fatigue, walking time, and the Disease Activity Score 28 (a clinical measure of arthritic disease). Additionally, WBC had no difference in the amount of the inflammatory biomarkers IL-6 and TNF-? when compared to the other treatments.
Can WBC Prevent or Treat Soreness?
A 2015 study says no. The authors combed a host of studies and only found 10 that compared WBC with placebo. In these randomized (or quasi-randomized) studies, 64 physically active participants (mostly men) underwent either WBC or placebo, 2 studies compared far-infrared treatment (i.e. Infrared Sauna). In none of the studies did the authors find a decreased soreness in those who had the WBC treatment compared to placebo or infrared treatment. The authors concluded that more research is required to make any claims on WBC's soreness reduction. Especially, since the extremely cold temperatures make WBC risky.
Conclusion
WBC is relatively new to the Regenerative Medicine, Recovery space. There are limited studies on WBC, which makes it hard to draw any conclusions regarding its benefits. Plenty of studies exist on non-WBC Cryotherapy (ice baths and ice packs), yet these show that Cryotherapy is not very effective. This fact in addition to the claim that WBC does not cool the muscles as well as an ice pack does make any WBC claim very suspect. Additionally, there are asphyxiation risks associated with WBC. The fact that Cryotherapy can hurt the beneficial aspects of PBMT, is worrisome. Researchers have concluded that PBMT used as a single treatment is the best for enhancing recovery post-exercise. Additionally, PBMT can help heal the tissue, not just relieve soreness/pain.