|If someone markets his program the way Hof does, i.e. as a means to "Become A 'Super' Version Of Yourself In Just 10 Short, Life Transforming Weeks" (WimHofMethod.com), you should rightly be skeptical.|
The study used a parallel randomized controlled design and was registered at ClinicalTrials.gov as NCT01835457. After approval by the local ethics committee of the Radboud University Nijmegen Medical Centre (CMO 2012/455), 30 healthy, nonsmoking, Dutch male volunteers were included in the trial.
Exclusion criteria were: febrile illness during the 2 wk before the endotoxemia experiment, taking any prescription medication, history of spontaneous vagal collapse, practicing or experience with any kind of meditation, or participation in a previous trial where LPS was administered.
|Table 1: Subject demographic characteristics (Kox. 2014).|
The study itself (which excluded several of the originally 30 subjects, because their reaction to endotoxemia, i.e. the influx of (potentially) pathogenic metabolic byproducts of bacteria into their blood was "odd" (i.e. too extreme as in too low or too high) was sequentially conducted in two identical blocks, each consisting of nine subjects in the trained group (of which six finally participated in the endotoxemia experiments) and six subjects in the control group. As the authors point out,
"[...t]his design was chosen to minimize the bias due to differences in the interval between the end of the training period and the endotoxemia experiments. As the aim of [their] study was to investigate the effects of the training intervention on the innate immune response in a standardized model of systemic inflammation, [they] did not assess the effects of the training intervention on immune system parameters in the absence of endotoxemia" (Kox. 2014).A schematic overview of the study design (one block) is depicted in Fig. S3. The trained group was trained by Dutch individual Wim Hof and three trainers who previously received an instructor course by Wim Hof to become a trainer. A medical doctor of the study team (L.T.v.E.) and the principal investigator (M.K.) were present during all training sessions (in Poland and in The Netherlands), and during the experimental endotoxemia experiments. The first 4 d of the training program took place in Poland and were most intensive.
|The Internet is full of praise for Hof's method, but that's not scientific eviden-ce (infographic from therenegade-pharmacist.com)... it does show that Hof is a good marketer, though ;-)|
(iii) Breathing techniques, consisting of two exercises: in the first exercise subjects were asked to hyperventilate for an average of 30 breaths. Subsequently, the subjects exhaled and held their breath for ∼2–3 min (“retention phase”). The duration of breath retention was entirely at the discretion of the subject himself. Breath retention was followed by a deep inhalation breath, that was held for 10 s. Subsequently a new cycle of hyper/hypoventilation began. The second exercise consisted of deep inhalations and exhalations in which every inhalation and exhalation was followed by breath holding for 10 s, during which the subject tightened all his body muscles. These two breathing exercises were also performed during the endotoxemia experiments. Additional element of the training program consisted of strength exercises (e.g., push-ups and yoga balance techniques).
|Figure 1: Study design. This block was carried out twice in identical fashion, resulting in 12 subjects in both groups that underwent experimental endotoxemia. CT, control subject; TR, trained subject (Kox. 2014).|
"[...t]he selected subjects practiced in a final training session led by Wim Hof on the day before the endotoxemia experiment day. Wim Hof was present to coach the subjects during the endotoxemia experiment days during the 3 h that the subjects in the trained group practiced the learned techniques. The control group did not undergo any training procedures throughout the study period" (Kox. 2014).To evaluate the effect of Hof's method on the subjects' immune system, the subjects, who had refrained from caffeine- or alcohol-containing substances 24 h before the start of the experiment, and food 10 h before the start of the endotoxemia experiment, were injected purified lipopolysaccharides from Escherichia coli, which were supplied as a lyophilized powder that was reconstituted in 5 mL saline 0.9% for injection and vortex mixed for at least 20 min after reconstitution.
"[...a] cannula was placed in an antecubital vein to permit infusion of 0.9% NaCl solution; the subjects received 1.5 L 0.9% NaCl during 1 h starting 1 h before endotoxin infusion (prehydration) as part of our standard endotoxemia protocol (29), followed by 150 mL/h until 6 h after endotoxin infusion and 75 mL/h until the end of the experiment" (Kox. 2016).To estimate the effect of the breathing techniques, the authors measured not just cardiorespiratory parameters, temperature, and symptoms, but also the levels of catecholamines, cortisol and plasma cytokines (stress), as well as the leukocyte count (immune reaction) and conducted correlation analyses of all these variables.
Figure 3: Correlation analysis (Kox. 2014).
- significant reductions of the proinflammatory mediators TNF-α, IL-6, and IL-8, which, in turn, correlated negatively with IL-10 levels.
- Brandt, Claus, and Bente K. Pedersen. "The role of exercise-induced myokines in muscle homeostasis and the defense against chronic diseases." BioMed Research International 2010 (2010).
- Kox, Matthijs, et al. "Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans." Proceedings of the National Academy of Sciences 111.20 (2014): 7379-7384.
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- Petersen, A., and B. Pedersen. "The role of IL-6 in mediating the anti inflammatory." J Physiol Pharmacol 57 (2006): 43-51.
- Van Der Poll, Tom, and Stephen F. Lowry. "Epinephrine inhibits endotoxin-induced IL-1β production: roles of tumor necrosis factor-α and IL-10." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 273.6 (1997): R1885-R1890.