FoundMyFitness · 2015-11-25 · Rhonda Patrick (host), Pierre Capel
Dr. Pierre Capel on the Power of the Mind & the Science of Wim Hof
30 claims checked against research: 3 contradicted 6 overstated 2 needing context 17 supported 2 unverified
6 Overstated
A gene expression study on white blood cells found that subjective loneliness altered at least 209 elementary biological functions across the immune system, metabolism, and hormones.
"In the case that somebody is lonely, uh in that article was at least 209 elementary functions in life were changed inside the immune system, inside metabolism, hormone levels, and whatever." (said at 0:11:40)
The landmark 2007 leukocyte gene expression study on subjective loneliness by Cole et al. identified 209 differentially expressed genes (transcripts) in circulating white blood cells between individuals experiencing high versus low chronic loneliness, rather than 209 distinct elementary biological functions. The altered gene profiles were primarily related to immune activation, pro-inflammatory signaling (NF-κB), transcription control, and suppression of type I interferon responses and mature B lymphocyte function. In addition, the original microarray study was a small cross-sectional investigation in 14 participants, representing preliminary correlational data rather than established causal effects across broad physiological functions.
Walking in nature compared to walking in an urban metropolitan area produces a significantly greater reduction in clinical symptoms of depression and anxiety.
"it found that people that took walks in nature versus, you know, in a metropolitan city area, had less clinical symptoms of depression, anxiety. So, they were both walking, they're both getting exercise, which we know also has positive benefits on depression. However, something about being immersed in nature had a much more significant antidepressant effect." (said at 0:19:05)
The referenced experimental paradigm (e.g., Bratman et al., 2015; Sudimac et al., 2022) compared the acute effects of walking in natural versus urban environments in healthy volunteers, assessing cognitive and neurobiological markers such as rumination, subgenual prefrontal cortex (sgPFC) activity, and amygdala reactivity. While these studies found that nature walks selectively reduced rumination and stress-related neural activity compared to urban walks, they were conducted in healthy cohorts and measured cognitive/neural risk factors rather than diagnosed clinical symptoms of depression or anxiety. Systematic reviews of nature exposure and nature-based prescriptions confirm moderate reductions in self-reported depression and anxiety score scales, but the claim that controlled nature walks demonstrated superior clinical antidepressant efficacy in clinical populations overstates the evidence.
- partial: Nature experience reduces rumination and subgenual prefrontal cortex activation. (Proceedings of the National Academy of Sciences of the United States of America 2015) · cited 919x in the literature
"We show in healthy participants that a brief nature experience, a 90-min walk in a natural setting, decreases both self-reported rumination and neural activity in the subgenual prefrontal cortex (sgPFC), whereas a 90-min walk in an urban setting has no such effects on self-reported rumination or neural activity." (abstract, results, passage verified)
pubmedfull study (doi) - partial: How nature nurtures: Amygdala activity decreases as the result of a one-hour walk in natur… (Molecular psychiatry 2022) · cited 195x in the literature
"Our findings reveal that amygdala activation decreases after the walk in nature, whereas it remains stable after the walk in an urban environment. These results suggest that going for a walk in nature can have salutogenic effects on stress-related brain regions, and consequently, it may act as a preventive measure against mental strain and potentially disease." (abstract, results, passage verified)
pubmedfull study (doi) - context: Effect of nature prescriptions on cardiometabolic and mental health, and physical activity… (The Lancet. Planetary health 2023) · cited 205x in the literature
"Nature prescriptions also had a moderate to large effect on depression scores (post-intervention standardised mean difference -0·50 [-0·84 to -0·16]; change from baseline standardised mean difference -0·42 [-0·82 to -0·03]) and anxiety scores (post-intervention standardised mean difference -0·57 [-1·12 to -0·03]; change from baseline standardised mean difference -1·27 [-2·20 to -0·33])." (abstract, results, passage verified)
pubmedfull study (doi)
In the early 1970s, using gamma interferon as a cancer therapy caused treated patients to develop psychosis.
"A very strong but sad example is that in the early '70s when gamma interferon was used as therapeutic agent for certain type of cancer, the only effect was that all these people who were treated ended up psychotic in the psychiatry ward because gamma interferon influences the immune system, but also influences the central nervous system." (said at 0:22:05)
While interferon therapies are well-documented to cross into or influence the central nervous system and cause neuropsychiatric adverse effects—such as depression (affecting approximately 20–50% of patients), anxiety, confusional states, and, in rarer instances, manic or psychotic symptoms—the claim that trials caused 'all' treated patients to become psychotic and end up in psychiatric wards is a substantial overstatement. Furthermore, psychiatric complications occur across interferon formulations (primarily interferon-alpha) rather than being the universal or sole outcome of early gamma interferon administration.
- partial: Neuropsychiatric adverse effects of interferon-alpha: recognition and management. (CNS drugs 2005) · cited 487x in the literature
"Acute IFN alpha-induced confusional states are typically characterised by disorientation, lethargy, somnolence, psychomotor retardation, difficulties with speaking and writing, parkinsonism and psychotic symptoms." (abstract, results, passage verified)
pubmedfull study (doi) - partial: Psychiatric Adverse Effects Of Interferon Therapy. (Clujul medical (1957) 2013) · cited 6x in the literature
"Clinical studies have reported a larger number of psychiatric symptoms consecutive to immunomodulating interferon therapy. The most frequent are depression, suicidal behavior, manic syndrome, anxiety disorders, psychotic disorders and delirium associated with an array of unspecific psychiatric symptoms" (abstract, results, passage verified)
pubmed
Administering the omega-3 fatty acid EPA alongside interferon prevents the development of interferon-induced depressive symptoms.
"there was a group that was given the interferon and there was a group that was given interferon and the marine omega-3 fatty acid eicosapentaenoic acid, EPA, which is also anti-inflammatory. They were given EPA with the interferon and they did not get the symptoms of depression" (said at 0:25:23)
In a randomized, double-blind, placebo-controlled trial of hepatitis C patients receiving interferon-alpha (IFN-α) therapy, 2 weeks of pretreatment with eicosapentaenoic acid (EPA) significantly reduced the incidence of IFN-α-induced depression compared to placebo (10% vs. 30%, p = 0.037) and delayed the average onset of depression from 5.3 weeks to 12.0 weeks (p = 0.002). However, claiming that patients 'did not get the symptoms of depression' overstates the absolute protective effect, as 10% of participants in the EPA group still developed depression.
After 7 weeks of regular meditation, brain activity shifts from a balanced 50/50 state toward greater left prefrontal cortex activity.
"Normally it's a 50/50 activity left-right, but with meditation it shifts a little bit to the left, and the left part is more the harmonious, well-being, feeling okay instead of the troublesome on the right. And this shift, and you make new neuronal, neuronal connections, new nerve cells are being made, gives you a really constant feeling of emotional stability. And you can measure the number of brain activities at different levels after 7 weeks of meditation, and you see a fantastic change to the positive." (said at 0:30:20)
The claim refers to seminal research on mindfulness-based stress reduction (notably Davidson et al., 2003), which evaluated an 8-week (rather than 7-week) meditation training program in 25 healthy employees compared to 16 wait-list controls. That randomized trial found a statistically significant shift toward greater left-sided anterior activation on electroencephalography (EEG), a pattern linked to positive affect and approach-oriented emotion regulation. However, framing baseline brain activity as a literal '50/50' split is a physiological oversimplification, as baseline frontal asymmetry varies widely across individuals as a trait marker. Furthermore, asserting that this practice generates 'new nerve cells' (adult neurogenesis) in the prefrontal cortex is not supported by human neuroimaging or cellular evidence, which primarily demonstrates functional changes and structural plastic alterations rather than cortical neurogenesis.
Sauna exposure alters brain function and modulates the opioid system by increasing sensitivity to endorphins.
"It also uh changes brain brain function as well. Um it changes the opioid system, endorphins, makes you more sensitive to them." (said at 0:54:21)
Sauna exposure and thermal stress stimulate the pituitary gland, leading to transient increases in circulating plasma levels of beta-endorphin and adrenocorticotropic hormone (ACTH). However, published human physiological studies demonstrate an increase in beta-endorphin release and concentration, not an increase in opioid receptor sensitivity or responsiveness ("making you more sensitive to them"). Confusing elevated circulating hormone levels with increased receptor sensitivity overstates the clinical and physiological evidence.
Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.