Best Hydration, Performance Nutrition & Supplement Advice From Dr. Andy Galpin(2022-2026)

Andy Galpin spends much of his public work correcting a single habit: athletes treat hydration, sodium, and supplements as fixed numbers instead of measurements. He spent much of his academic career at California State University, Fullerton and became executive director of the Human Performance Center at Parker University in 2024. Across his work with elite performers and his public teaching, the throughline is that individual testing beats population averages when training stress, heat, and sweat losses rise.

That framing runs directly counter to how most people approach hydration and performance nutrition. Drink eight glasses of water. Cut sodium. Take a multivitamin. Galpin's position, laid out across long-form interviews with Andrew Huberman and on his own podcast, is that generic defaults stop describing reality when someone trains hard in heat, sweats heavily, or trains at altitude. The sections below break down his framework for sweat rate testing, sodium replacement, VO2 max training, heat acclimation, and where supplements actually belong in the hierarchy.

01The Huberman Lab and Perform episodes on Galpin's hydration nutrition and supplements

This roundup draws on Galpin's 2022 Huberman Lab conversation on strength, muscle size, and endurance, his 2023 episode on optimal nutrition and supplementation, and Perform episode 31 on nutrition, hydration, and performance fueling. The Huberman conversations introduce the Galpin Equation, sweat and sodium testing, and the supplement hierarchy. The 2026 episode returns to the four fueling elements around training: glucose, amino acid availability, hydration, and gastrointestinal tolerance. The studies below test those practical claims against exercise physiology and sports nutrition evidence.

02How to test your sweat rate before choosing a fluid plan

Galpin's starting point for hydration is a body-mass protocol that has been standard in exercise physiology for decades but rarely makes it into consumer advice. Weigh yourself nude immediately before a training session and again immediately after, track any fluid consumed during the session, and account for urine output if it happens. Estimate sweat rate with this formula: (pre-session body mass - post-session body mass + fluid consumed - urine output) divided by session duration. Use kilograms and liters for mass and fluid, and hours for duration, so the result is liters per hour. Each kilogram of body mass lost approximates one liter of sweat only when intake and urine are accounted for and the session lasts one hour.

The American College of Sports Medicine's fluid replacement position stand recommends customized replacement because sweat rate and sweat electrolyte content vary between people.¹ In a retrospective analysis of 506 athletes, Baker and colleagues reported whole-body sweat rates from 0.26 to 5.73 liters per hour across sports and environmental conditions.² That range is the reason Galpin pushes back on any single hydration number applied across a training population. A 3x/week gym lifter training in an air-conditioned facility and a summer marathoner training outdoors at noon are not the same hydration problem, even if both call themselves athletes.

The practical output of the test is a personal number in liters or ounces lost per hour of a specific training condition, not a single lifetime target. Galpin recommends repeating the test across different conditions (indoor vs outdoor, cool vs hot, easy vs hard) because sweat rate shifts with heat, humidity, exercise intensity, and heat acclimation status, not just body size. For readers who want the fuller replacement math including sweat sodium concentration, the complete guide to hydration walks through post-session rehydration targets in more detail.

03Replace sodium from measured sweat losses not a daily target

Galpin treats sodium the same way he treats fluid: as something to measure rather than assume. In Baker's 506-athlete dataset, regional sweat sodium values ranged from about 290 to 2,410 mg per liter, while predicted whole-body values ranged from about 420 to 1,630 mg per liter.² Two athletes losing the same volume of sweat during the same workout can therefore have very different sodium losses, which is why Galpin resists blanket sodium targets in either direction.

The current Dietary Guidelines for Americans recommend less than 2,300 mg of sodium per day for most people age 14 and older, while also noting that highly active people may need more to offset sweat losses.³ That is a general-population reference. It is not an individualized athlete prescription. A heavy-sweating endurance or team-sport athlete needs a training-day sodium plan built from sweat testing and health context. Someone with hypertension or salt-sensitive blood pressure needs clinician-guided sodium management first. The mechanics of matching sodium intake to session length and sweat losses are covered step by step in the amateur athlete's sodium mistake and in sodium loading for endurance racing.

04Rehydrate with 1.25 to 1.5 liters of fluid for every kilogram lost

Once the sweat-rate number exists, Galpin turns it into a rehydration target instead of leaving it as trivia. When an athlete needs rapid rehydration after substantial dehydration, especially with another session within about four hours, post-exercise replacement guidance commonly uses 1.25 to 1.5 liters of fluid for every kilogram of body mass lost. The ratio is a rapid-recovery tool rather than a universal daily drinking target.

These rows describe net fluid deficit from body-mass change. They do not estimate total sweat volume when fluid is consumed during the session. Use the formula above for total sweat volume. Galpin's caveat on that table matters as much as the numbers in it. Drinking large volumes of hypotonic fluid beyond what an athlete loses can lower plasma sodium when intake exceeds renal water excretion. Sodium losses may contribute during long or salty sessions, and sodium can support rehydration. It does not make overdrinking safe. Athletes should use body-mass change and session conditions to avoid finishing heavier from fluid intake.

05Scale carbohydrate to the training day and keep protein more stable

Galpin pushes back on the idea of a single daily macro target the same way he pushes back on a single hydration number. His framing ties carbohydrate and protein intake to what a specific training day demands rather than to a static ratio applied every day of the week. A day built around a long aerobic session or repeated high-intensity intervals needs meaningfully more carbohydrate around the session than a day built around lower-body strength work at moderate volume, even if total weekly training hours are similar.

Protein is the one macronutrient Galpin treats as closer to fixed for exercising or resistance-trained adults. The ISSN position stand supports 1.4 to 2.0 g per kilogram of body mass per day for most exercising individuals. A meta-analysis of resistance-training studies found that gains in fat-free mass plateaued near 1.6 g per kilogram per day, with an upper confidence limit near 2.2 g per kilogram per day.⁹¹⁰ During energy restriction, the higher-intake exception applies specifically to lean, resistance-trained athletes. A review estimates 2.3 to 3.1 g per kilogram of fat-free mass per day, scaled to leanness and the severity of the deficit.¹¹ For resistance-trained adults, a protein-distribution review proposes roughly 0.4 g per kilogram per meal across at least four feedings to reach 1.6 g per kilogram per day. Three to five meals is a practical range that can accommodate that target, not a physiological requirement.¹² Carbohydrate is the lever he actually periodizes, scaling up around the sessions that deplete glycogen fastest, intervals, long endurance work, repeated-sprint or team-sport days, and scaling down on lower-demand training or rest days. That structure lines up with the broader carbohydrate periodization approach covered in carb periodization for lifters and hybrid athletes, which walks through the same day-by-day logic in more depth.

06Train VO2 max with easy aerobic volume and hard repeatable intervals

Galpin repeatedly returns to VO2 max, maximal oxygen uptake during exercise, as one of the strongest modifiable fitness predictors of long-term health outcomes. A cohort study published in JAMA Network Open followed 122,007 adults referred for symptom-limited treadmill testing at Cleveland Clinic. It found that cardiorespiratory fitness had an inverse association with all-cause mortality that was comparable to or stronger than several traditional risk factors studied, including smoking, diabetes, and coronary artery disease, with the lowest-fitness group carrying roughly five times the mortality risk of the highest-fitness group.⁴ The American Heart Association's 2016 scientific statement recommended that cardiorespiratory fitness be assessed and recorded as a clinical vital sign alongside blood pressure and heart rate.⁵

For training, Galpin's practical position is that most lifters and recreational athletes underinvest in the top end of aerobic capacity because it does not build muscle the way resistance training does and it is uncomfortable to train directly. His recommended structure pairs a large volume of easy, conversational-pace aerobic work (commonly framed as zone 2 training) with a smaller weekly dose of hard intervals. In his strength, muscle size, and endurance discussion, Galpin separates several-minute VO2 max intervals from shorter sprint bouts. The site's practical VO2 max guide translates the longer work into four to six repeats of roughly two to four minutes at a hard, repeatable pace, with enough recovery to preserve quality across the set. Galpin also discusses shorter bouts of roughly 20 to 90 seconds for sprint and anaerobic-capacity work. Those bouts train a different quality. The dietary nitrate and beetroot juice protocol is one of the few supplement interventions Galpin discusses as having a plausible, dose-dependent effect on the oxygen cost of submaximal exercise, though he is clear it will not substitute for the training itself.

07Heat acclimation expands plasma volume and then increases sweat rate

Galpin frames heat acclimation as a training block with a measurable physiological endpoint, not a comfort adaptation. Repeated heat exposure during training can expand blood plasma volume, reduce heart rate at a given workload, and lower core temperature at a given workload. Post-exercise sauna may serve as a protocol-dependent adjunct, but it is not established as equivalent to exercise heat acclimation. A 2015 review by Périard and colleagues, covering heat acclimation research across endurance sport, describes these adaptations and notes that timing varies by protocol and athlete, with many programs building over roughly one to two weeks.⁶

The practical implication Galpin draws out is timing: athletes should start a heat-acclimation block roughly 7 to 14 days before competition when the schedule allows. Some adaptations begin after several sessions, yet enough exposure and recovery are needed to protect taper-phase training quality. He also flags that heat adaptation increases sweat rate as a downstream effect, meaning an athlete who successfully heat-acclimates needs to retest fluid and sodium losses rather than carrying forward pre-acclimation numbers. The full sauna-based protocol, including how to sequence heat exposure around a training week without wrecking recovery, is detailed in heat acclimation for endurance athletes.

08Training, sleep, and nutrition outrank creatine, caffeine, and the rest of the stack

Galpin is known for organizing performance interventions into a hierarchy rather than a shopping list, an approach he has laid out in interviews and in his co-authored book on training science. Training, sleep, and nutrition sit at the base of that hierarchy because they support performance across more situations than any single supplement. Supplements sit above that base, and within supplements, Galpin distinguishes ingredients with repeated trial evidence from a larger category with preliminary or inconsistent support.

The International Society of Sports Nutrition's position stand on creatine monohydrate, updated in 2017 after several decades of trial data, remains a reference point for a supplement with genuinely strong evidence: consistent gains in strength, power output, and lean mass across hundreds of controlled trials, with a safety record that now spans over 20 years of research in both athletic and clinical populations.⁷ Readers who want the dosing and loading-phase specifics can find them in the ultimate guide to creatine. Caffeine gets a similar tier, with the ISSN's position stand supporting doses of roughly 3 to 6 mg per kilogram of body mass for measurable improvements in endurance and power output, though caffeine metabolism, influenced in part by CYP1A2 genotype, is only one factor affecting effective dose and sleep cost.⁸ The caffeine for performance breakdown covers that genotype-dependent dosing in full.

09Use electrolyte capsules with a measured hydration plan

Galpin's stance on electrolyte supplements, the capsules and drink mixes marketed heavily to endurance and hybrid athletes, is more measured than the marketing around them. He treats them as a delivery mechanism for a number that sweat testing can help refine, not as a product that fixes hydration on its own. Athletes without sweat sodium data can still make a conservative plan from session duration, conditions, body-mass change, and health context, then adjust it when better data becomes available. An athlete who reaches for a capsule with 1,000 mg of sodium per serving without that context is still guessing, just with a different failure mode.

The distinction he draws is between food-based sodium, salting meals, adding a sodium source to a pre-training snack, and product-based sodium during longer sessions where carrying enough food is impractical. Shorter or lower-sweat sessions can often be managed through ordinary meals and a conservative fluid plan. Capsules and drink mixes may earn their place on multi-hour endurance days, hot-weather team-sport sessions, or events where sweat losses accumulate faster than food-based sodium can realistically replace them, which is the same threshold used in sodium loading for endurance racing.

10Exercise cramps more often come from fatigue and fluid loss than from magnesium

Galpin's testing-first habit shows up again when the conversation turns to muscle cramping, a symptom many lifters and endurance athletes reflexively treat with magnesium. His position is consistent with the current clinical literature. Magnesium deficiency can cause cramps, yet many exercise-associated cramps are better explained by neuromuscular fatigue, pacing, and a sudden jump in training load. Fluid and sodium losses become more relevant when the session is long, hot, or unusually sweaty. Reaching for a magnesium supplement before checking those variables treats the wrong problem in many cramping cases. The distinction between neuromuscular and electrolyte-driven cramping mechanisms, along with when magnesium supplementation actually helps, is broken down further in why muscle cramps happen during exercise.

11Repeat sweat testing when training conditions change

The gap between Galpin's testing-based approach and how most people actually train comes down to measurement. Sweat-rate testing requires a scale and a training log kept across multiple sessions in different conditions. Sweat sodium concentration requires a sweat patch or laboratory-style test. Symptoms can flag a mismatch, but they cannot estimate sodium concentration. VO2 max testing in a lab is not accessible to most recreational athletes, so wearable-estimated VO2 max can provide a rough trend estimate for some people. It should not be treated as a substitute for accurate laboratory measurement.

The practical version of the framework is a testing plan that fits the training conditions an athlete actually uses. Run several sweat-rate measurements under representative conditions and repeat them when environment, intensity, clothing, equipment, or heat acclimation changes. Build sodium planning from measured sweat volume, session conditions, health context, and appropriately validated sodium testing when available. Treat symptoms as a reason to reassess or stop, not as a dosing basis. Keep the supplement list focused on interventions with relevant trial evidence.

An athlete can apply this framework without building a full sports-science protocol. Run several sweat-rate tests across the session types that matter, adjust the plan when conditions change, and keep tracking only the measures that change a decision. That is a smaller commitment than a full sports-science protocol and a more defensible one than drinking more simply because a symptom appeared. One useful step toward measurement can close more of the gap than an elaborate plan that never gets used.