HoldsUp

FoundMyFitness · 2026-01-22 · Rhonda Patrick (host)

Dr. Rhonda Patrick: Maximizing Healthspan with Exercise, Sauna, & Cold Exposure

81 research-tied claims examined: 2 contradicted 11 overstated 8 context 53 supported 7 unverified

8

Needs context

0:11:53Rhonda Patrick (host)needs contextmoderate

As humans age, the heart shrinks and myocardial tissue becomes stiffer.

"generally speaking, as we age, our heart shrinks and it gets stiffer. It's stiffer with age." (said at 0:11:53)

The speaker's assertion that myocardial tissue becomes stiffer with age is well-supported by human magnetic resonance elastography and Doppler echocardiographic studies, which demonstrate increased myocardial shear stiffness and impaired early diastolic filling with advancing age. However, the claim that the heart "shrinks" is inaccurate or requires significant context: while left ventricular end-diastolic volume and cavity diameter tend to decrease with age, total left ventricular mass remains overall unchanged or slightly increases due to concentric wall thickening (concentric remodeling), rather than true cardiac atrophy or shrinking of the organ overall.

0:16:56Rhonda Patrick (host)needs contextmoderate

Lactate is more energetically favorable to convert into cellular energy than glucose, requiring less energy to produce ATP.

"In fact, it's more energetically favorable than glucose. It takes less energy to make energy from lactate than it does from glucose." (said at 0:16:56)

The claim that lactate is more energetically favorable or requires less energy to convert into cellular energy than glucose is contextually accurate for recipient consumer tissues, but requires qualification. When recipient cells (such as cardiac myocytes or neurons) take up exogenous lactate, it is converted directly to pyruvate by lactate dehydrogenase (generating cytosolic NADH) and enters mitochondrial oxidation without requiring the initial priming investment of two ATP molecules consumed during the hexokinase and phosphofructokinase steps of glycolysis. However, on a whole-body level, lactate originates from upstream glycolysis in producer cells, so the reduced initial activation cost for recipient cells represents localized substrate partitioning rather than a net gain in total thermodynamic yield.

0:30:44Rhonda Patrick (host)needs contextmoderate

In the United States, someone has a heart attack approximately every 30 seconds.

"And in the US, a heart attack, someone's having a heart attack like every 30 seconds." (said at 0:30:44)

The statement is close to national surveillance figures but slightly overstates the frequency for acute myocardial infarction alone. According to nationwide cardiovascular surveillance data compiled by the American Heart Association (AHA) and the Centers for Disease Control and Prevention (CDC), approximately 805,000 individuals experience a myocardial infarction (heart attack) annually in the United States. This corresponds to an average rate of approximately one heart attack every 40 seconds, rather than every 30 seconds. Higher frequencies (such as an event every 30 to 34 seconds) typically describe broader categories, such as total coronary events or overall cardiovascular disease deaths.

0:34:33Rhonda Patrick (host)needs contexthigh

Finnish saunas typically operate at temperatures between 174°F and 179°F with 20% to 30% humidity.

"In Finland, they do typically their sauna temperatures around 174 to 179° Fahrenheit. They also often will put water on hot rocks to create humidity, about 20 to 30% humidity." (said at 0:34:33)

Standard clinical and epidemiological literature defines traditional Finnish saunas as operating at higher temperatures (80°C to 100°C, or 176°F to 212°F) and lower relative humidity levels (10% to 20%). While 174°F to 179°F (roughly 79°C to 82°C) touches the lower bound of typical Finnish sauna exposure, describing this narrow band as the typical operating range underestimates the upper temperatures commonly used in Finland, while slightly overestimating the typical baseline relative humidity.

0:51:58Rhonda Patrick (host)needs contextmoderate

Young healthy men who wore a cooling suit set to 50°F for 2 hours daily for 1 month experienced an almost 50% increase in brown adipose tissue.

"We know from studies that young healthy people, in this case they were men, if they walked around with a cooling suit that was cooling their body to about 50° F for 2 hours daily, after 1 month, they had about an almost 50% increase in brown adipose tissue." (said at 0:51:58)

Human cold-acclimation studies show that repeated mild cold exposure over 4–6 weeks increases brown adipose tissue (BAT) volume and metabolic activity by approximately 30% to 50% in young healthy men. However, the speaker conflates details from different experimental designs: in the 1-month acclimation study by Lee et al. (PMID: 24954193), five healthy men spent 10 hours overnight in a temperature-controlled room at 19 °C (66.2 °F), not walking around in a cooling suit set to 50 °F for 2 hours daily. Other daily 2-hour cold-exposure protocols have used cold-air rooms (typically 15–17 °C / 59–62.6 °F) over 6 weeks rather than 1 month in a wearable cooling suit.

0:53:35Rhonda Patrick (host)needs contextmoderate

Deliberate cold exposure between exercise bouts improves endurance athletic performance, including running times and reaction times in athletes.

"In fact, there's actually been several studies that have shown elite tennis players, rowers, let's see, what else? There've been a variety of different endurance runners that in between their sort of sets that they're doing, if they engage in deliberate cold exposure, they actually improve their running time or their reaction time, whatever metric is being measured, but it's essentially increasing or improving their athletic performance." (said at 0:53:35)

The host claims that deliberate cold exposure between exercise bouts (often termed intermittent cooling or per-cooling) improves athletic performance metrics, such as running times or reaction times, in athletes like tennis players and endurance runners. Published meta-analyses and randomized crossover trials confirm that intermittent cooling interventions (such as ice vests, head/neck cooling, palm cooling, or cold towels between bouts) attenuate heat-induced performance declines and can improve subsequent power output and endurance performance, particularly in hot environments. However, the benefits are primarily observed during exercise under environmental heat stress or high metabolic heat loads, rather than in standard or cold conditions.

1:04:54Rhonda Patrick (host)needs contextmoderate

Performing endurance exercise in a fasted state enhances mitochondrial adaptations compared to a fed state.

"some of the mitochondrial adaptations that you're going to experience from your endurance training will also be enhanced somewhat if you do them in a fasted state." (said at 1:04:54)

Fasting before endurance exercise can acutely augment specific upstream metabolic signaling cascades linked to mitochondrial adaptation, such as AMPK phosphorylation and the expression of certain lipid metabolism genes. However, systematic reviews and chronic randomized training trials show mixed and variable results: while acute molecular signaling is often heightened in the fasted state (or blunted by pre-exercise feeding), chronic training in a fasted versus fed state frequently results in similar long-term increases in mitochondrial enzyme activities (such as citrate synthase) and overall mitochondrial capacity.

1:23:55Rhonda Patrick (host)needs contextmoderate

Magnesium oxide has very poor bioavailability compared to organic magnesium salts such as magnesium citrate, malate, taurate, and glycinate.

"The classic one that people used to take, magnesium oxide, terrible. It's just not bioavailable at all. So forget that form. When it comes to supplementation, some of the best and most bioavailable forms are the the organic salts. So you're getting magnesium citrate, magnesium malate, magnesium taurate. And then magnesium glycinate is a really good one." (said at 1:23:55)

Multiple randomized controlled and comparative crossover trials in humans confirm that organic magnesium salts (such as magnesium citrate and amino-acid chelates/glycinate) exhibit significantly higher gastrointestinal absorption and bioavailability than magnesium oxide, which is poorly soluble. However, claiming that magnesium oxide is 'terrible' and 'not bioavailable at all' is an overstatement: magnesium oxide is absorbed to a modest degree (typically estimated at ~4% fractional absorption in classic metabolic studies) and can raise body magnesium levels, though substantially less effectively and with higher gastrointestinal side effects than organic formulations.

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.