Train hard, but keep it short: lifting to support healthy testosterone

The Short Version

Resistance training is one of the few natural levers that reliably pushes testosterone up. It works as a short, sharp stress: mechanical load plus metabolic strain signal the body to release androgens [1][4][5]. The experts here agree that the dose that helps is intense and brief. Duncan French's research protocol is six sets of ten at about 80% of max with only two minutes' rest, done about twice a week [1]. Huberman's hormone episodes stress heavy loads, not training to failure, and lifting before cardio [4][5]. Kyle Gillett adds the other half of the picture: regularly training vigorously for more than about an hour is "not hormonally helpful." The worst blood work he sees comes from hard training combined with big calorie deficits [2]. Session length, rest between sets, recovery days, sleep and total life stress all decide whether training builds testosterone or wears it down [1][2][4][5].

Table of contents

What They Said

Duncan French: intensity plus volume, short rest, then recover

Dr. Duncan French is vice president of performance at the UFC Performance Institute. He did his PhD in a research group that published a long run of papers on how resistance training affects hormones [1]. When Huberman asks how lifting heavy weights actually tells the body to release testosterone, French answers: "I think it's a stress response, right? It's mechanical stress and it's metabolic stress" [1]. His own research focused on adrenaline, noradrenaline and the stress-hormone system that sits upstream of that release [1].

Where the testosterone comes from. In women, the adrenal glands are the only source of the training-induced rise. It's much smaller than in men, but French says good data show women can still improve their anabolic environment with resistance training [1]. In men, "The field is divided, presently" on how much of the acute rise comes from the adrenals and how much from the testes. It's also divided on whether short-term spikes or long-term baseline levels matter more for muscle growth [1]. That's an honest caveat worth keeping in mind: a post-workout spike isn't automatically the same thing as higher testosterone over time. French also points out that testosterone acts well beyond muscle, on tendons, ligaments, nerves and bone, calling it "a magic, a magic hormone" with many effects on adaptation [1].

The key principle. French says testosterone responds to both an intensity factor and a volume factor, while growth hormone is driven mostly by intensity [1]. Huberman admits this is the opposite of what he had assumed, and that much of what circulates online has it backwards [1].

The protocol. His group's testosterone-driving protocol was six sets of ten reps at about 80% of one-rep max, usually in the back squat, with about two minutes of rest between sets [1]. If a participant couldn't finish ten reps, the researchers lowered the weight so all ten got done, because the point was to sustain both intensity and volume [1]. They tested alternatives and rejected them:

• German volume training (ten sets of ten) couldn't be sustained at 80%. The load dropped off too much.
• Ten sets of six allowed heavier weights but didn't create the same metabolic load and lactate that help signal more testosterone release [1].

Rest is the overlooked variable. French says longer rest lets the body clear lactate and waste products, which weakens the stimulus. He explains that with longer rest "You're allowing the flushing of the body, the removal of waste products, you know, lactate to be removed from the body and then the metabolic environment is reduced" [1]. For pure muscle growth, someone doing six sets of ten with two minutes' rest will likely gain more than someone doing the same with three minutes [1].

Huberman takes this personally: "the way that I've been training slow and lazy is not necessarily the best way to go." He realizes he "could in theory do a 45 or 60 minute session where I pack in more, more work per unit time," even if it means lifting less weight [1]. He concludes that "the old adage of high intensity short duration is probably the way to go" [1]. French agrees. We're inherently lazy and want to feel refreshed between sets, but the training stimulus often depends on the metabolic environment in that moment [1].

How often. Huberman describes the workout as "intense, but short" and asks how many days a week a typical person can do it "and sustain progress" [1]. French wouldn't have a beginner jump into it. He suggests about two sessions a week of something that demanding, since it involves real suffering from load and lactate [1]. For a weekend warrior who wants to stay in shape and look good, he'd pair those two very hard sessions with others that either drop the intensity and use higher rep ranges (12, 15, 20), or drop the volume and raise the intensity, to hit different goals [1].

Short-term stress helps; long stress doesn't. Huberman notes the popular assumption: "We always hear about stress suppressing testosterone, stress suppressing the immune system, all these terrible things, but in the short term, you're saying it can actually increase the release of testosterone." French answers: "Correct" [1]. His PhD work, inspired by older studies of combat parachute jumpers, found that athletes facing a workout they knew would be brutal had adrenaline and noradrenaline rising about 50 minutes before it started [1]. Those with the biggest stress response sustained force output longer, and those with lower arousal performed worse [1]. Repeated exposure to the same challenge produces less stress response over time, so the stressor has to evolve [1]. Huberman's summary is that discomfort is beneficial as long as the stress doesn't go on too long [1].

Recovery is part of the program. French says the best athletes aren't necessarily training harder than anyone else. They can do quality work "again and again and again," day after day, which makes recovery central to performance [1]. For skill work he'd take a 90-minute quality session over a three-hour one: "As soon as fatigue is influencing that repetition, it's time to stop" [1]. He also treats cold as a stressor, noting that to your nervous system an ice bath, a lion or a hard workout all trigger the same adrenaline cascade: "Your body does not know the difference" [1]. There are now robust data, he says, that cold can reduce strength, power and muscle growth by dampening mTOR and other growth signaling. So elite sport avoids cold during heavy muscle-building blocks and saves it for competition phases, when the gains "should be in the bank" [1].

Fuel the work. French rarely recommends a fully ketogenic diet for athletes in high-intensity, stop-start sports, because those efforts need carbohydrate [1]. He calls his approach "needs-based eating": more carbohydrate when training is intense, less when you're mostly walking around or taking time off [1]. He suggests testing any new approach for about 12 weeks while logging training, mood and sleep, since 15 people doing the same workout will have 15 different responses [1]. He calls his overall philosophy "adaptation-led programming" [1].

Kyle Gillett: the one-hour threshold and the danger of hard training on too little food

Dr. Kyle Gillett, a physician board-certified in family medicine and obesity medicine who specializes in hormone optimization, supplies the clinical half of the story: what over-training looks like in blood work [2][3].

Resistance training as a pillar. In Gillett's framework, diet and exercise are the two strongest lifestyle levers, and "For hormone health, specifically resistance training is particularly helpful" [3]. He opens with a principle that applies directly to training volume: "The law of diminishing returns applies. So doing a little amount of what I call lifestyle interventions over a long period of time is going to be far more helpful or efficacious than doing a lot and then doing nothing" [3].

Huberman's own warning signs. Huberman describes what happens when he overdoes it: "when I go out for runs that are excessively long, two hour runs, or I spend 90 minutes in the gym too frequently, start to feel like garbage. Everything suffers. My sleep starts to suffer" and no amount of food seems to help him recover [2]. His best routine, he says, is:

• a 10-minute warm-up
• 45 to 50 minutes of weight training in the 6 to 10 rep range with two to three minutes' rest, rarely to failure
• easy jogging on other days [2]

He adds that his blood profiles, including testosterone and estrogen, move the wrong way if he skips a weekly 45-minute jog [2].

Gillett's dose. "For really vigorous exercise around three to four times a week is very sustainable over a long period of time. On top of that, you could add in three or four more instances of less vigorous exercise" [2]. By vigorous he means weight training or high-intensity intervals. Less vigorous means zone 2 cardio, where you can just hold a conversation [2]. Lighter weight training can be done more often and still helps collagen in tendons and ligaments [2].

The hour. Gillett says studies of vigorous exercise show that "it is not hormonally helpful to train, especially regularly train vigorously for longer than an hour" [2]. Huberman sums up the consensus: "it sounds like for most people that hour of work is really the threshold" and "an hour a day of exercise is just a great program that most anyone can follow. And beyond an hour, you start running into challenges" [2]. He adds that the occasional long session is fine: "the occasional 90-minute or two-hour workout is no big deal. But if you start doing that more than once every two months, I think you're headed for trouble" [2].

What over-training does to blood work. The worst blood work Gillett sees combines heavy vigorous training with a large calorie deficit, often with low carbohydrates and too little iron or vitamin D, and produces very low free testosterone [2]. Quick-result tactics like cutting all carbs or jumping into six intense days a week may undermine long-term hormone health [2]. His guiding principle is consistency: "So 80 or 90% of the benefit over many, many months is far better than 100%, but only half the time" [2]. He also flags the nervous-system cost. Very hard morning workouts can leave cognitive workers drained for the day. Huberman adds that training before 9 a.m. gives him more energy, while mid-morning sessions bring an afternoon crash [2].

Food and body fat. The calorie story cuts both ways. "If you're obese or you have metabolic syndrome caloric restriction will improve your testosterone," Gillett says. But a study in young, healthy men found testosterone fell with restriction [3]. For lean people, restriction means fewer building blocks for hormones, a more catabolic state, less growth hormone and IGF-1 signaling, and higher SHBG, so free androgens and estrogens drop [2]. He also notes that the more zone 2 cardio someone does, the less important long stretches of calorie restriction become [3].

What training releases locally. Gillett adds a mechanism that supports French's high-volume work. Referring to the growth-hormone-raising regimens French described, he says "During those training exercises it usually does it transiently for a period of a few hours and a lot of this IGF1 is released by the muscle itself" [2]. That local, muscle-made IGF-1 "is likely part of the reason why you get a improved body composition response after exercise" [3].

Supplements come later. Gillett's ladder puts supplements after the basics. Creatine, for example, "does slightly increase total testosterone" and raises conversion to DHT [2]. Huberman's rule, which Gillett shares, is behaviors first, then nutrition, then supplements, then prescription drugs only with a real need and a doctor [2].

Andrew Huberman's hormone episodes: heavy, not to failure, lift before cardio, protect sleep

In his solo episodes on testosterone and estrogen, Huberman builds the case from mechanism [4][5].

Why testosterone makes hard work feel different. Testosterone binds to the amygdala, the brain's threat-detection hub, "and changes the threshold for stress." That's what Huberman means when he says "testosterone has this incredible effect of making effort feel good" [4][5]. Competition itself raises testosterone: "short-lived competitive scenarios, can liberate testosterone from the adrenals," and even winning works indirectly through dopamine signaling to the pituitary [4][5]. A hard, short training session is a controlled version of that kind of challenge.

The lifting prescription. Huberman says the more mechanistic studies show heavy weight training, but not training to failure, produces the biggest testosterone increases. That means roughly a one-rep max up to about six to eight repetitions, in both men and women, with effects lasting about a day and sometimes up to 48 hours [4][5].

Order matters. "Endurance activity if performed first leads to decreases in testosterone during the weight training session as compared to the same weight training session done first followed by endurance activity" [4][5]. His conclusion: "weight training first and doing cardio type endurance activity afterward is the right order of business," but "when these are done on separate days it doesn't seem to have an effect" [4][5]. High-intensity intervals and sprinting somewhat mimic the neural activity of moving heavy loads [4][5].

Why chronic stress and poor sleep undercut training. Huberman explains that sleep adjusts testosterone and estrogen largely through cortisol. Cholesterol is the raw material for these hormones, but "the cholesterol will turn into cortisol and not testosterone or it'll turn into cortisol and not estrogen if stress levels are too high" [4][5]. Deep sleep also supports the cells in the testes and ovaries that make hormones and sperm or eggs [4][5]. Sleep apnea is one of the behaviors most associated with low testosterone or estrogen compared with age-matched peers [4][5]. Illness works against you too: "inflammatory cytokines like IL-6 are bad for sex-steroid hormones" [4][5].

Cold and heat. Huberman says ice baths and cold showers may help sex hormones indirectly, probably through a rebound in blood flow to the gonads. But "we don't know whether or not cold and heat directly affect the production of testosterone and estrogen" [4][5].

Caution. He repeatedly warns that "more is definitely not better" when it comes to hormones, and recommends blood work before and during any attempt to change them [4][5].

Where They Agree, and Where They Don't

Where they agree.

• Resistance training raises testosterone. French shows it experimentally [1], Gillett names it a core pillar [3], and Huberman ranks heavy lifting as a leading behavioral tool [4][5].
• Intense and short beats long and slow. French's protocol is dense and brief with short rest [1]. Huberman concludes that high intensity, short duration "is probably the way to go" [1]. Gillett and Huberman put the ceiling for regular vigorous sessions at about an hour [2].
• Hard days need company. French pairs about two brutal sessions with easier, varied ones [1]. Gillett suggests three to four vigorous sessions plus three to four lighter ones [2]. Huberman keeps easy jogs on other days [2].
• Acute stress helps; chronic stress hurts. French shows short-term stress can boost testosterone and performance, while Huberman notes it shouldn't go on too long [1]. Huberman's cortisol-competition mechanism explains why ongoing stress costs hormone output [4][5]. Gillett's over-trained, under-fed patients show it in their labs [2].
• Recovery, food and sleep are part of the program. French puts recovery at the center of elite performance and matches carbohydrate to training [1]. Gillett warns against pairing hard training with large deficits and low carbs [2]. Huberman calls sleep and breathing the foundation [4][5].

Where they differ.

• Heavy low reps or moderate reps with volume? Huberman's summary of the literature favors heavy loads, roughly one to six-to-eight reps, not to failure [4][5]. French's protocol is ten reps at 80%, and he explicitly found that ten sets of six with heavier weight didn't create the same metabolic load and lactate signal [1]. The two views aren't incompatible. French argues testosterone responds to intensity and volume together, and he keeps the load high enough to be demanding (80%) while adding enough reps and short enough rest to build metabolic stress. Huberman's range emphasizes load. Both avoid true failure: French lowers the weight rather than letting sets fail [1], and Huberman says rarely to failure [2][4][5].
• How many hard days? French suggests about two sessions a week of his specific protocol [1], while Gillett allows three to four vigorous sessions [2]. The difference is mostly one of definition. French's protocol is deliberately punishing, and Gillett's "vigorous" covers any weight training or intervals.
• Rest periods. French wants about two minutes and says three minutes weakens the growth stimulus [1]. Huberman's own routine uses two to three minutes [2], and he admits that his "slow and lazy" habit is probably not optimal [1].
• Cold. Huberman sees possible indirect benefits for sex hormones through blood flow [4][5]. French warns that cold during muscle-building phases can blunt strength, power and growth [1]. They're measuring different things, hormone levels versus muscle adaptation, so the practical takeaway is to keep cold away from the hours after a hypertrophy session in a building phase.
• How much the acute spike matters. Huberman describes the post-lifting rise as lasting about a day, sometimes up to 48 hours [4][5]. French cautions that the field is still divided on whether these short-term spikes or long-term baseline levels drive muscle growth [1].

Why It Works

The sources describe several interlocking mechanisms:

• Mechanical and metabolic stress are the signal. Heavy loads and accumulated lactate act as a stressor that triggers androgen release through adrenal and gonadal pathways [1]. That's why French keeps the load at 80% and the rest short: the metabolic environment itself is part of the message [1].
• Testosterone responds to volume and intensity; growth hormone mainly to intensity. Enough total work at a demanding load is needed for the testosterone response [1].
• Muscle makes its own growth signal. After training, IGF-1 rises for a few hours, much of it released by the muscle itself. This local IGF-1 likely helps explain the improved body composition after exercise [2][3].
• Short stress is anabolic; long stress is catabolic. Brief stressors raise adrenaline and can increase testosterone and performance [1]. Sustained stress diverts cholesterol toward cortisol instead of testosterone [4][5], and repeated long vigorous sessions push blood work in the wrong direction [2].
• Energy availability matters. Hard training on a big deficit leaves fewer building blocks for hormones, a more catabolic state, less growth-hormone and IGF-1 signaling and higher SHBG, so free testosterone falls [2]. Missing iron or vitamin D make it worse [2].
• Sequence matters within a session. Endurance work done first lowers testosterone during the lifting that follows [4][5].
• Testosterone feeds back into effort. By raising the amygdala's stress threshold, testosterone makes effort feel good. That's part of why well-dosed training can be self-reinforcing [4][5].
• Recovery is where adaptation happens. The soreness and inflammation after training are the stimulus for adaptation, which is why French warns against blunting them with cold during building phases [1].

Where It Applies, and Where It Doesn't

Where it applies.

• Adults who already know how to lift safely. French wouldn't start a beginner on the six-by-ten protocol [1], and Huberman frames his question for someone who knows "the difference between a dumbbell and a barbell" [1].
• Both sexes. Huberman says the heavy-lifting response occurs in men and women [4][5]. French notes women's rise is smaller and comes only from the adrenals, but still meaningfully improves their anabolic environment [1].
• People carrying extra body fat, for whom training plus sensible calorie restriction can raise testosterone [3].

Where it needs adjusting.

• Lean people cutting hard. For young, healthy, lean people, calorie restriction is likely to lower testosterone, and combining it with heavy training is the pattern Gillett links to the worst labs [2][3].
• Endurance-heavy athletes and long-session lovers. Regular vigorous sessions over an hour, or long runs done often, are where Gillett and Huberman see hormones and recovery suffer [2]. Endurance athletes also need more carbohydrate to fuel long efforts [3].
• Beginners. Start with easier, higher-rep work before brutal short-rest sessions [1].
• People with poor sleep, apnea or ongoing illness. Training can't make up for cortisol-driven or cytokine-driven suppression [4][5].
• Anyone considering hormones or supplements. Training is the natural route. Beyond it, Gillett and Huberman urge blood work and physician guidance [2][4][5].

If you have symptoms of low testosterone, or you plan to combine hard training with aggressive dieting, get blood work and talk to a physician before and during the change.

What To Do With It

1. Schedule one or two short, brutal lifting sessions a week. Use French's template: six sets of ten at about 80% of one-rep max on a big compound lift like the back squat, lowering the weight when needed so every set reaches ten reps [1].
2. Time your rest and keep it short. Aim for about two minutes between sets rather than three, so the metabolic stress builds [1]. Pack the work into a 45 to 60 minute session instead of drifting [1].
3. Cap regular vigorous sessions at about an hour. Treat 90-minute or two-hour sessions as rare exceptions, not more than about once every two months [2].
4. Build the week around three to four vigorous and three to four easy sessions. Vary the non-brutal lifting days with higher reps (12, 15, 20) or lower volume at higher intensity, and add zone 2 cardio where you can hold a conversation [1][2]. Keep at least one easy jog or cardio session in the week, as Huberman does [2].
5. Lift before cardio. If both happen in one session, do the heavy loads first and the endurance work afterward. On separate days, order doesn't matter [4][5].
6. Don't train to failure routinely. Heavy loads, rarely to failure, is the common thread across Huberman's routine and the studies he cites [2][4][5].
7. Eat for the work. Don't pair hard training with large calorie deficits or zero carbs, especially if you're lean. Match carbohydrate intake to training intensity and check iron and vitamin D [1][2].
8. Protect sleep and manage ongoing stress. Breathe through your nose, deal with suspected apnea, and treat poor sleep as a hormone problem, since high stress diverts cholesterol toward cortisol [4][5]. If long sessions are wrecking your sleep, as Huberman describes, cut the duration [2].
9. Keep cold away from building phases. If muscle growth is the goal, avoid ice baths right after hypertrophy sessions and save cold for recovery-focused periods [1].
10. Run a 12-week test and log it. Keep a simple log of training, mood and sleep for about three months, and get blood work before and during any change to see whether your hormones are actually moving [1][2][4][5].

Sources

1. Dr. Duncan French: How to Exercise for Strength Gains & Hormone Optimization · Huberman Lab
2. Dr. Kyle Gillett: Tools for Hormone Optimization in Males · Huberman Lab
3. Dr. Kyle Gillett: How to Optimize Your Hormones for Health & Vitality · Huberman Lab
4. How to Optimize Testosterone & Estrogen | Huberman Lab Essentials · Huberman Lab
5. The Science of How to Optimize Testosterone & Estrogen · Huberman Lab