Acute responses: protocol matters more than “heavy lifting” in general
Classic work by Kraemer and others showed that protocols using large muscle mass, moderate-to-high intensity, higher volume, and short rest intervals produce the biggest immediate rises in testosterone, GH, and cortisol (typically 15–30 minutes post-exercise). Low-volume, high-intensity work with long rests produces smaller or non-significant changes in those hormones when total work is matched or low.
A direct comparison (McCaulley et al.) equated volume across three squat-based sessions:
- Hypertrophy: 4 × 10 at 75% 1RM, 90 s rest
- Strength: 11 × 3 at 90% 1RM, 5 min rest
- Power: jump squats at 0% 1RM
Only the hypertrophy session produced significant immediate rises in testosterone, cortisol, and SHBG versus rest. Strength and power sessions did not.
Häkkinen and Pakarinen (1993) compared 20 sets of 1RM squats versus 10 × 10 at ~70% 1RM (same 3 min rests) in strength athletes. The 10 × 10 session raised total and free testosterone, cortisol, and GH. The 20 × 1RM session produced essentially no testosterone change and only a small GH rise. Lactate tracked GH. Morning testosterone was still suppressed the next two rest days after both sessions.
True 1RM testing or competition attempts are even lower volume than those 20 singles. Expect modest anabolic-hormone responses and a larger catecholamine (epinephrine/norepinephrine) and arousal response. Anticipatory catecholamine rises occur before heavy work; men who maintain force better across a hard session often show higher pre- and during-exercise catecholamines. These support force production, contraction rate, energy availability, and blood flow.
Free-weight compounds (squat vs. leg press at similar intensity) typically elicit larger testosterone and GH responses than machines, consistent with greater muscle mass and stabilization demand. Exercise order that hits large muscles first also tends to produce bigger IGF-1 and testosterone responses in normal-weight men.
Competition and powerlifting-specific data
In an international powerlifting meet, saliva cortisol and DHEA rose after the event in both men and women. Testosterone rose significantly only in men. End-competition cortisol related to performance in women; end-competition testosterone related to performance in men. No meaningful change occurred from the day before to weigh-in.
Some cross-sport endocrine snapshots have reported relatively low resting testosterone (and sometimes low free T3 or GH-axis markers) in male powerlifters versus other athletes. Causes are unclear—selection, body composition, training style, or sampling timing—and should not be over-interpreted as “powerlifting lowers T.” Age and physique differences across sports also contribute.
Testosterone, cortisol, and the T:C ratio
Testosterone supports muscle protein synthesis, neuromuscular function, and recovery. Acute post-lift rises of ~15–40% are common with sufficient volume and large-muscle work; they are brief. Resting levels often do not rise chronically despite strength and size gains. The more durable effects appear to be upregulation of muscle androgen receptors (after an initial dip in some protocols) and favorable body composition. Higher baseline muscle AR content has correlated with 1RM in some data.
Cortisol is catabolic and rises with metabolic stress, volume, and psychological demand. The testosterone-to-cortisol ratio is used as a recovery/overreaching marker. A drop of ~30% from an individual’s baseline has been proposed as a flag for insufficient recovery (not a diagnosis by itself). Chronically high cortisol can suppress the HPG axis. Powerlifters managing high CNS and joint stress need to watch total load, sleep, and life stress to keep this ratio from drifting down for weeks.
GH, IGF-1, and local vs. systemic signals
GH rises more with volume, lactate, and short rests than with pure 1RM work. Circulating IGF-1 can rise after resistance exercise (partly GH-driven hepatic output), and some training studies show modest chronic IGF-1 increases, especially early in a program or in older adults. Muscle-produced IGF-1 splice variants (including mechano-growth factor) respond to mechanical load and are more relevant to local remodeling than a brief blood spike.
Recent reviews and unilateral-training studies argue that acute systemic T/GH/IGF-1 spikes are not required for hypertrophy or strength gains and do not reliably predict them. Mechanical tension, mTOR signaling, and intramuscular factors (including AR content and load-dependent AR-DNA binding) appear primary. High-load work can increase AR-DNA binding even without large changes in circulating androgens.
Insulin is nutrition-dependent (post-workout carbs + protein). Thyroid hormones influence metabolic rate; isolated findings of lower free T3 in some strength athletes are not well established as causal.
Practical takeaways for 1RM and powerlifting
- Do not design sessions around “maximizing the hormone spike” if the goal is a bigger squat, bench, or deadlift. Specificity (heavy singles, doubles, triples, long rests, technique) drives neural and technical adaptations. Volume work still has a place for muscle mass, work capacity, and some endocrine/recovery stimulus.
- Catecholamine and arousal management (warm-up structure, psych-up, caffeine, environment) matter more on max-attempt days than chasing testosterone.
- Recovery variables that support a better T:C environment: adequate calories (especially not prolonged deficits), sleep, not stacking endless high-intensity volume, and managing non-training stress. Overreaching with daily max-effort work can raise exercise-induced catecholamines while performance drops.
- Compound free-weight movements and large-muscle-group work still produce the most reliable acute endocrine responses when you want them (e.g., off-season or accessory blocks).
- Women show smaller testosterone responses but still adapt; GH and IGF-1 patterns can differ by sex and training status.
- Individual variation is large. Training status, age, obesity, and genetics blunt or amplify responses.
Anabolic-androgenic steroids and related PEDs produce supraphysiological effects on both size and neural drive; powerlifting cycles historically emphasize more androgenic compounds for performance than typical bodybuilding mass cycles. That is a separate medical and regulatory topic.
The dominant drivers of a bigger 1RM remain progressive overload on the specific lifts, technique, bodyweight/muscle mass in the relevant ranges, and recovery—not the size of a 20-minute post-workout hormone bump.