HoldsUp

Huberman Lab · 2026-07-20 · Andrew Huberman (host), Tommy Wood

Accelerate Learning & Increase Cognitive Capacity | Dr. Tommy Wood

78 research-tied claims examined: 3 contradicted 5 overstated 4 context 65 supported 1 unverified

5 Overstated
0:27:50Tommy Woodoverstatedmoderate

Meta-analyses of dance interventions in older adults indicate that ballroom and line dancing produce the greatest improvements in cognitive function among physical activity modalities.

"the best evidence is for ballroom and line dancing, which generally requires—and so there are meta-analyses of these interventions in older adults showing that ballroom and line dancing have the greatest effect on cognitive function." (said at 0:27:50)

Meta-analyses of randomized controlled trials demonstrate that dance interventions have a modest to moderate positive effect on cognitive function in older adults. When comparing dance subtypes, a 2025 Bayesian network meta-analysis found ballroom dancing was the most effective dance modality for global cognition (SMD = 0.89), whereas other dances (such as tango or square dancing) primarily improved balance, mobility, or mental health. However, asserting that meta-analyses prove ballroom and line dancing produce the 'greatest effect' across physical activity modalities overstates the literature: overall dance effect sizes on cognition are modest (g = 0.27), and systematic reviews note that evidence is currently insufficient to definitively rank dance types or declare dance superior to all other physical activity modalities.

0:58:44Andrew Huberman (host)overstatedlow

Having a smartphone in close proximity, even if placed in a bag beneath one's chair and turned off, significantly impairs cognitive performance and focus.

"Are you familiar with this recent study about phone on the table, phone in the bag? We would just remind people that if your phone has to be out of the room, even if it's in your bag beneath your chair turned off, [GUEST1: you can still focus, but there's a cost.] HOST: Your cognitive flexibility, etc., really suffer." (said at 0:58:44)

The host is referencing the prominent 'brain drain' study by Ward et al. (2017), which reported that the mere physical presence of a smartphone (on a desk or in a bag, even when turned off or silenced) reduced available working memory capacity and attentional control compared to leaving it in another room. However, stating that cognitive function 'really suffers' significantly overstates the strength and consistency of the evidence. Subsequent pre-registered direct replications (such as Hartmann et al., 2022) failed to replicate the effect across all conditions, and meta-analytic evidence reveals substantial heterogeneity with mixed effects across different cognitive domains.

1:49:23Andrew Huberman (host)overstatedmoderate

A moderate-intensity resistance training or cardio session transiently triples or quadruples baseline cortisol levels.

"It was interesting to me to dive into the literature on cortisol and find that a moderate-intensity resistance training session or cardio session, probably a little bit easier than the 4x4, will triple one's baseline levels of cortisol, like or quadruple it." (said at 1:49:23)

While exercise can stimulate the hypothalamic-pituitary-adrenal axis to elevate cortisol, the claim that moderate-intensity cardio or resistance training triples or quadruples baseline cortisol levels substantially overstates the magnitude of this response. Exercise intensity research establishes a threshold effect (typically around 60% VO2max), where 30 minutes of moderate-intensity exercise (60% VO2max) elevates circulating cortisol by approximately 40% (1.4-fold) and low-intensity exercise (40% VO2max) causes little to no increase. Even vigorous exercise at 80% VO2max increases cortisol by ~83% (less than a doubling). Multi-fold increases (3x to 4x) typically occur only under extreme exhaustive or high-intensity, short-rest protocols, not routine moderate-intensity sessions.

1:53:16Tommy Woodoverstatedmoderate

White matter makes up approximately 60% of the human brain, which is a higher proportion than in other species.

"In the human brain, white matter makes up approximately 60%, more than most other species—any other species." (said at 1:53:16)

The speaker overstates both the proportion of white matter in the human brain and the uniqueness of this proportion compared to other species. In humans, cerebral white matter comprises roughly 40% to 50% of total brain volume (and ~50–60% of the telencephalic/forebrain volume depending on anatomical boundary definitions), with gray matter constituting the remaining majority. Furthermore, comparative neuroanatomy demonstrates that white matter scaling follows a universal allometric power-law relationship (exponent ~4/3) across mammals: as brain size increases, white matter volume scales disproportionately faster than gray matter to maintain connectivity. Consequently, human white matter volume matches allometric predictions for a primate of our brain size, and larger-brained mammals (such as elephants and large cetaceans) possess equivalent or higher proportions of subcortical white matter.

2:00:26Tommy Woodoverstatedmoderate

Studies using a one-week creatine monohydrate loading protocol show significant increases in brain creatine concentrations.

"So, some of the studies that use traditional creatine monohydrate and look at creatine levels in the brain, they did use a loading protocol for a week and then you see significant increases in brain creatine." (said at 2:00:26)

The speaker claims that studies using a 1-week creatine loading protocol show significant increases in brain creatine concentrations. In contrast to skeletal muscle (where a 5-7 day loading protocol reliably increases creatine concentrations by ~20%), brain creatine uptake is much slower due to the blood-brain barrier and endogenous synthesis. Landmark 1H-MRS studies showing significant brain creatine increases typically used multi-week supplementation protocols (e.g., 20 g/day for 4 weeks in Dechent et al. 1999). RCTs specifically evaluating 7-day loading protocols (e.g., in healthy youth, PMID 28079396) failed to find significant increases in brain creatine levels. Thus, stating that a 1-week loading protocol results in significant brain creatine increases overstates the speed and evidence of brain creatine accumulation.

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.