HoldsUp

Brady Holmer

Brady Holmer is an endurance athlete and researcher working in exercise physiology and cardiovascular health. His published research examines the cardiovascular impacts of exercise, including high-intensity interval training and cardiac troponin release in individuals with cardiovascular disease or type 2 diabetes. He has also authored studies investigating the effects of sleep deprivation on endothelial function as well as the impact of energy drinks and exogenous ketones on athletic performance.

23 claims checked on air: 2 context 2 contradicted 2 overstated 14 supported 3 unverified

What they said on air

0:04:16supportedhighWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Standard metabolic equivalent of task (MET) categories classify light activity as 0 to 3 METs, moderate activity as 3 to 6 METs, and vigorous activity as greater than 6 METs.

"If, you know, you're doing a light activity that might be somewhere between, you know, like 0 to 3 METs, moderate activity 3 to 6 METs, vigorous activity over 6 METs, and it's basically saying what's your oxygen consumption or your, you know, calorie burn during these activities." (said at 0:04:16)

The standard physical activity classifications and Compendium of Physical Activities categorize physical activity intensity based on Metabolic Equivalent of Task (MET) values: light-intensity activity as 1.6 to <3.0 METs (or 1.1–2.9 METs, within the <3 MET range), moderate-intensity activity as 3.0 to 5.9 METs (or 3 to 6 METs), and vigorous-intensity activity as 6.0 METs or higher. A MET represents the ratio of the work metabolic rate to a standard resting metabolic rate (oxygen consumption or energy expenditure). Published accelerometry and physical activity calibration literature routinely uses these standard MET cut-points (<3 METs for light, 3–6 METs for moderate, and >6 METs for vigorous activity).

0:10:24supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

The study published in Nature Communications by Stamatakis et al. analyzed wrist-worn accelerometer data from over 73,000 UK Biobank adults aged 40 to 79 tracked over an average of 8 years.

"So for this study they focused on more than 73,000 adults from the UK Biobank who were aged 40 to 79. So that's kind of important I think as well, they were, you know, middle-aged to older aged adults, and they tracked them over 8 years. So the follow-up period in the study was 8 years on average. And the important part of the study is how they measured their physical activity. It was measured using these wearable devices, these wrist-worn accelerometers." (said at 0:10:24)

The speaker accurately summarizes the study cohort and methodology from the 2025 Nature Communications paper by Stamatakis et al. The study analyzed data from 73,485 UK Biobank participants who wore wrist-worn accelerometers and were followed prospectively for a mean duration of 8.0 years.

0:18:33supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

The Stamatakis et al. study controlled for reverse causation and healthy user bias by excluding individuals with baseline disease and those who developed disease within the first 12 months.

"Well, they controlled for that in this study by excluding people who if you developed any of these diseases within the first 12 months of the study they were excluded. And additionally anybody with a disease at baseline was excluded." (said at 0:18:33)

In the UK Biobank accelerometry investigations led by Stamatakis and colleagues examining vigorous intermittent lifestyle physical activity (VILPA) in relation to mortality (Nature Medicine, 2022) and incident cancer (JAMA Oncology, 2023), the analytic design explicitly addressed reverse causation and baseline health confounding by excluding individuals with pre-existing baseline diseases (such as cardiovascular disease or cancer) and conducting landmark/sensitivity analyses excluding incident events occurring within the first year or more of follow-up.

0:25:43needs contextlowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

According to the Stamatakis et al. study, 1 minute of vigorous physical activity is equivalent to 53 to 94 minutes of light physical activity across major health outcomes.

"So for all of the main outcomes including cancer light activity u one minute of vigorous activity was equal to 53 to 94 minutes um of light activity." (said at 0:25:43)

In a prospective UK Biobank cohort study of 73,485 participants using device-measured physical activity, Stamatakis et al. (PMID 41057301) found that for a standardized 5% to 35% risk reduction, the median light physical activity (LPA) equivalent per 1 minute of vigorous physical activity (VPA) ranged from 53 minutes (for all-cause mortality) to 94 minutes (for type 2 diabetes). However, the authors explicitly specified that this 53- to 94-minute equivalence range applied to non-cancer outcomes, rather than including cancer.

0:26:34supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

According to the Stamatakis et al. study, 1 minute of vigorous physical activity is equivalent to 94 minutes of light activity for type 2 diabetes prevention.

"Um for diabetes prevention, it was nearly an hour and a half. So 94 minutes of light activity was equal to 1 minute of vigorous uh intensity activity" (said at 0:26:34)

In a prospective cohort study of 73,485 UK Biobank participants using wrist-worn accelerometers (mean follow-up: 8.0 years), Stamatakis and colleagues evaluated the risk-equivalent durations of different physical activity intensities. They found that for equivalent risk reduction in type 2 diabetes, the median light physical activity (LPA) equivalent per 1 minute of vigorous physical activity (VPA) was 94 minutes.

0:26:44supportedlowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

According to the Stamatakis et al. study, 1 minute of vigorous physical activity is equivalent to 73 minutes of light activity for cardiovascular disease mortality and 86 minutes for major adverse cardiovascular events.

"for the cardiovascular disease outcomes. Um 73 minutes for cardiovascular disease mortality, 86 minutes for um major adverse cardiovascular events." (said at 0:26:44)

In a 2025 prospective cohort study of 73,485 UK Biobank participants with accelerometer tracking (mean follow-up of 8.0 years), Stamatakis and colleagues investigated wearable device-based health equivalencies across physical activity intensities. They reported that for non-cancer outcomes, the median light physical activity (LPA) equivalent per 1 minute of vigorous physical activity (VPA) ranged from 53 minutes for all-cause mortality to 94 minutes for type 2 diabetes, with cardiovascular disease outcomes falling directly in this range (including 73 minutes for CVD mortality and 86 minutes for major adverse cardiovascular events). As an observational cohort study, residual confounding cannot be completely ruled out.

0:26:58supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

According to the Stamatakis et al. study, 1 minute of vigorous physical activity is equivalent to 156 minutes of light-intensity physical activity for cancer mortality.

"And then for cancer mortality, this one was the largest one. Um 1 minute of vigorous activity was equal to 156 minutes. So nearly 2 and a half hours of light intensity um activity." (said at 0:26:58)

A prospective cohort study of 73,485 UK Biobank participants by Ahmadi, Stamatakis, and colleagues evaluated accelerometer-measured health equivalencies across physical activity intensities. They found that for equivalent risk reductions in cancer mortality, 1 minute of vigorous physical activity (VPA) was equivalent to approximately 156 minutes of light-intensity physical activity (LPA), representing the largest equivalence ratio observed among the evaluated health outcomes.

0:27:36supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

According to the Stamatakis et al. study, light-intensity physical activity produced only minor risk reductions (5-10%) without significant benefit or strong dose-response for cardiovascular mortality, stroke, or heart attacks.

"Um but there were some outcomes. So say for cardiovascular disease mortality, stroke, heart attacks. It actually didn't really seem to have much of a benefit. Doing more light intensity physical activity didn't significantly reduce. So there were, you know, 5 to 10% risk reductions, which the authors actually didn't consider to be meaningful in the context of this study." (said at 0:27:36)

In prospective analyses of UK Biobank accelerometry data led by Emmanuel Stamatakis and colleagues examining incidental physical activity and health equivalence (e.g., Stamatakis et al., Circulation 2025; Nature Communications 2025), light physical activity (LIPA / light-intensity physical activity) was found to have weak associations and dose-response relationships with cardiovascular disease (CVD) mortality, major adverse cardiovascular events (MACE, including stroke and myocardial infarction), and all-cause mortality compared to moderate or vigorous intensities. In non-exercising adults, LIPA showed only a subtle inverse gradient that was generally weak, requiring exceptionally high daily durations (e.g., >130 min/day) to demonstrate minimal risk reductions, whereas moderate and vigorous physical activity produced strong, clinically significant risk reductions.

0:32:12unverifiedvery lowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Moderate physical activity shows a linear dose-response risk reduction up to about 50 minutes per day, after which additional moderate activity provides no further risk reduction.

"up to about 50 minutes per day, you kind of saw this linear dose response, uh, this risk reduction up to about 50 minutes per day of moderate activity. And then after that, you didn't see more risk reduction basically from getting more moderate activity." (said at 0:32:12)

No published record matching the claim that moderate physical activity shows a linear dose-response risk reduction up to about 50 minutes per day after which additional moderate activity provides no further risk reduction was located; this does not prove the claim false.

0:32:28contradictedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Light physical activity provides about a 10% to 15% risk reduction, but shows no further dose-response benefit with up to 2 to 3 hours per day.

"So you do some light activity, you get about a 10 to 15% risk reduction, but doing more of that up to say even 2 to three hours a day of that extra light activity didn't really seem to reduce risk much more, right?" (said at 0:32:28)

The claim that light physical activity confers only a 10% to 15% risk reduction without further dose-response benefits beyond 2 to 3 hours per day is contradicted by large accelerometer-based meta-analyses and prospective cohort studies. A landmark harmonized meta-analysis of prospective cohorts published in the BMJ demonstrated a substantial graded dose-response reduction in all-cause mortality across increasing quartiles of light physical activity (hazard ratios of 0.60, 0.44, and 0.38 compared to the least active quarter, representing up to a ~62% risk reduction). Subsequent large-scale prospective cohort analyses similarly show continuous, non-linear dose-response risk reductions for light activity extending up to 5 to 6 hours per day.

0:36:48overstatedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

In volume-matched randomized controlled trials, high-intensity interval training consistently produces greater improvements in vascular endothelial function and arterial stiffness compared to moderate-intensity training.

"if you read any of the randomized control trials too just comparing moderate intensity training to high intensity interval training if you look at the effects on endothelial function like you mentioned in artery stiffness it's it's not it doesn't even come close like when even when they're volume matched. So you say you do the same amount of volume of moderate intensity and high intensity interval training. High-intensity interval training always wins in terms of improving vascular function." (said at 0:36:48)

The claim that high-intensity interval training (HIIT) "always wins" and "doesn't even come close" compared to moderate-intensity continuous training (MICT) for improving vascular endothelial function and arterial stiffness overstates the scientific evidence. Systematic reviews and meta-analyses of randomized controlled trials confirm that HIIT generally produces statistically significant, modest advantages over MICT in improving endothelial function (flow-mediated dilation improvements of 1.43% to 2.6% over MICT). However, findings for arterial stiffness are mixed: while a 2025 meta-analysis found a statistically significant reduction in pulse wave velocity favoring HIIT (-0.10 m/s), an earlier meta-analysis found no statistically significant difference between HIIT and MICT for central arterial stiffness. The evidence supports a general benefit of HIIT over MICT, but the effect size is modest rather than overwhelming, and the superiority is not universal across all arterial stiffness measures.

0:39:22supportedhighWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

An increase in stroke volume is the primary physiological adaptation responsible for improvements in VO2 max.

"And I think one of the key adaptations there is obviously again the the increase in in stroke volume that you get. That's one of the best predictors or that's the main thing that increases when VO2 max increases. So if you look at these studies showing, you know, what's the main adaptation that gives you a better VO2 max, it's higher stroke volume because that gives you a greater cardiac output." (said at 0:39:22)

The claim is supported by exercise physiology literature. In healthy humans, maximal oxygen uptake (VO2 max) is primarily limited by convective oxygen delivery rather than peripheral muscle extraction capacity. Because maximal heart rate remains unchanged or slightly decreases with endurance training, the training-induced increase in maximal cardiac output is driven almost entirely by an increase in maximal stroke volume, making stroke volume expansion the principal central adaptation underpinning improvements in VO2 max.

0:42:23supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Starting around age 30 to 40 and continuing into the 50s and beyond, VO2 max declines by approximately 10% per decade without exercise intervention.

"after about age 30 to 40 into your 50s your VO2 max starts to decline about 10% per decade so if you're not doing something to maintain that yes you can build it up as much as you can into your 30s and 40s, but if you aren't engaging in moderate to vigorous intensity exercises at age 40, 50, 60, 70, your VO2 max is just going to continue to drop 10% per decade" (said at 0:42:23)

Large meta-analyses of cardiorespiratory fitness across the adult lifespan show that maximal oxygen consumption (VO2 max) declines at a rate of approximately 8.7% to 10% per decade in sedentary men and approximately 10% per decade in sedentary women after young adulthood. While regular exercise maintains higher absolute baseline fitness levels at any given age, VO2 max declines progressively with age across all activity levels.

1:01:59overstatedlowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Studies by Kerry Courneya show that exercise directly destroys circulating tumor cells.

"even the studies that, you know, Kerry Courneya was involved in and that we kind of researched and you guys talked about in your podcast. It's like exercise directly kills it kills the circulating tumor cells" (said at 1:01:59)

A small pilot clinical trial co-authored by Kerry Courneya (n=23 stage I–III colon cancer patients) demonstrated that 6 months of aerobic exercise led to significant reductions in circulating tumor cell (CTC) counts compared to usual care. However, the study did not establish that exercise directly kills CTCs; the authors explicitly noted that direct destruction is a hypothesis alongside indirect mechanisms mediated by host factors such as insulin, BMI, and adhesion molecules.

1:03:42unverifiedvery lowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Vigorous-intensity exercise induces higher increases in adrenaline, cortisol, and growth hormone than low-intensity exercise.

"obviously with these vigorous intensity activities, you get more adrenaline, more cortisol, more growth hormone. Anything that you get with low intensity activity is sort of just heightened with high-intensity activity" (said at 1:03:42)

No published record matching the claim that vigorous-intensity exercise induces higher increases in adrenaline, cortisol, and growth hormone than low-intensity exercise was located; this does not prove the claim false.

1:05:42supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Type 2 fast-twitch muscle fibers atrophy and lose strength first during aging, before type 1 slow-twitch fibers.

"type 2 fibers are the type of fibers that will atrophy first and lose strength first with with age. So you lose type 2 fibers first and then we move down to losing those type 1 or weakening of type 1 fibers." (said at 1:05:42)

Human skeletal muscle biopsy studies and mechanistic reviews consistently demonstrate that age-related sarcopenia is characterized by preferential atrophy and remodeling of type II (fast-twitch) muscle fibers, leading to early declines in muscle power and size, whereas type I (slow-twitch) fibers are comparatively preserved until later in the aging process.

1:20:30supportedhighWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Physical activity guidelines previously required moderate or vigorous exercise to be accumulated in bouts of at least 10 minutes, but that minimum bout duration was removed from the guidelines.

"The guidelines used to say 75 to 150 minutes of vigorous or 150 to 300 minutes of moderate performed in bouts of 10 minutes or longer, and they actually nixed that part from the guidelines. It's not even in there anymore. So they no longer acknowledge that you need to do it in 10 minutes or more." (said at 1:20:30)

The speaker's statement is accurate. The 2008 Physical Activity Guidelines for Americans originally specified that aerobic physical activity should be accumulated in episodes of at least 10 minutes. In the updated 2nd edition of the guidelines (released in 2018), this minimum bout duration was officially removed based on evidence showing that moderate-to-vigorous physical activity provides health benefits regardless of how the duration is accumulated throughout the day.

1:27:42supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Studies by Martin Gibala and others show that performing regular exercise snacks for 6 to 8 weeks improves VO2 max by 2 to 3 mL/kg/min in untrained individuals.

"with exercise snacks, people like Martin Gibala and other groups have actually done studies on them and they've shown improvements in VO2 max of 2 to 3 milliliters per kilogram of oxygen with just 6 to 8 weeks maybe of just performing these exercise snacks regularly." (said at 1:27:42)

Randomized trials by Martin Gibala and colleagues have demonstrated that brief 'exercise snacks' (such as 20-second cycling sprints or 60-step vigorous stair climbing bouts performed 3 times daily, spaced 1 to 4 hours apart, 3 days per week for 6 weeks) improve cardiorespiratory fitness (peak oxygen uptake / VO2peak) in sedentary or inactive young adults. In these 6-week protocols, VO2peak typically increased by approximately 4% to 5% (equivalent to ~1.5 to 2.5 mL/kg/min from baseline values around 35 mL/kg/min), matching the claimed timeframe and effect magnitude.

1:31:45contradictedhighWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Physical activity guidelines were updated to include an upper range of 300 minutes of moderate-intensity activity, whereas earlier guidelines only specified 150 minutes.

"the 150 to 300 minutes, which actually had been increased a little bit. They recently added the 300 minutes; it used to be just 150." (said at 1:31:45)

The claim that physical activity guidelines previously specified only 150 minutes of moderate-intensity activity and only recently added the 300-minute upper range is contradicted by guideline history. The target range of 150 to 300 minutes per week of moderate-intensity aerobic activity (or 75 to 150 minutes of vigorous activity) was already established in the first edition of the US Physical Activity Guidelines for Americans in 2008 and was reaffirmed in the 2018 second edition, rather than being a newly increased or added target.

1:46:30unverifiedvery lowWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Clinical studies demonstrate that older adults with type 2 diabetes can safely perform Norwegian 4x4 high-intensity interval training at 85% maximum heart rate multiple times per week.

"there are, I mean, hundreds of studies on, let's just keep using the Norwegian 4x4, for example, but adults can do that protocol safely, effectively, several times per week... we had people who were 65 years old with diabetes coming in and they were doing a couple of these 4x4 protocols a week, 85% heart rate max." (said at 1:46:30)

No published record matching the claim that older adults with type 2 diabetes can safely perform Norwegian 4x4 high-intensity interval training at 85% maximum heart rate multiple times per week was located; this does not prove the claim false.

1:47:30supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Without vigorous exercise stimulus past a certain age, cardiac tissue will continue to stiffen and undergo fibrosis as part of the aging process.

"Going back to what Ben Levine was talking about, I mean, at a certain age, past a certain age, if you don't engage in the vigorous exercise, you're just not going to adapt, especially with regard to the cardiac the cardio cardiac adaptations, the cardiovascular system. The heart just needs that extra stimulus and without it, the heart's just going to continue to stiffen, fibrosis as you age." (said at 1:47:30)

The speaker accurately summarizes research led by Dr. Benjamin D. Levine and colleagues on exercise and cardiac aging. Sedentary aging leads to progressive left ventricular stiffening and decreased compliance. Interventional trials demonstrated that high-intensity exercise training started in middle age (around age 45–64) successfully reduces left ventricular stiffness and improves cardiac compliance (Howden et al., 2018). However, when vigorous exercise training was initiated later in life (in sedentary individuals older than 65 years), it failed to reverse cardiac stiffening, indicating a window of cardiovascular plasticity where specific exercise stimulus is required before age-related stiffening becomes irreversible (Fujimoto et al., 2010).

1:51:05needs contextmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Relative Energy Deficiency in Sport (RED-S) occurs when physical activity exceeds nutritional energy intake, and female athletes—particularly in endurance disciplines—are more prone to underfueling than male athletes.

"relative energy deficiency in sport, RED-S, is a if if you're doing more activity than you're fueling your body for. And women are um more prone to kind of that underfueling than maybe males are, um especially kind of in the endurance sports realm." (said at 1:51:05)

Relative Energy Deficiency in Sport (RED-S/REDs) is defined by the International Olympic Committee (IOC) as a syndrome of impaired physiological function caused by low energy availability (LEA), where dietary energy intake is insufficient to support exercise energy expenditure alongside basic bodily functions. Endurance disciplines carry particularly high rates of LEA and RED-S. While historically recognized primarily in females (formerly termed the Female Athlete Triad), systematic reviews and recent IOC consensus updates show that underfueling is also highly prevalent among male endurance athletes, with some meta-analyses demonstrating comparable rates of LEA across both sexes.

1:54:37supportedmoderateWhy Vigorous Exercise Is 4–10x More Effective Than Moderate

Excessive volumes of high-intensity interval training (HIIT) can impair mitochondrial function.

"There are study interesting study that I read recently it showed that if you do too much it actually like harms your mitochondria and causes mitochondrial dysfunction." (said at 1:54:37)

A landmark 2021 intervention study by Flockhart et al. published in Cell Metabolism demonstrated that excessively high training loads of high-intensity interval training (HIIT) induced a striking reduction in intrinsic mitochondrial respiration and function in healthy volunteers, accompanied by impaired glucose tolerance.

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