In 1985, a research team at McMaster University recorded the blood pressure of five experienced bodybuilders while they pushed leg press sets to failure. The group average peaked at 320/250 mmHg, and one lifter went past 480/350. A typical resting reading is around 120/80. The same recordings showed mouth pressures of 30 to 50 Torr, which told the authors that part of the surge came from a Valsalva manoeuvre (MacDougall et al., 1985).
That is the short version of the question behind how to breathe when lifting weights. Holding your breath under a heavy bar does something measurable. Whether it helps, hurts or does both depends on the load, the lift and the person holding it.
What the Valsalva manoeuvre actually is
The Valsalva manoeuvre means trying to exhale against a closed glottis, the gap between your vocal cords. Air cannot leave, so pressure builds in your chest and abdomen. Lifters often call this bracing, and many describe it as pushing the belly out against a belt.
The pressure is real and large. A 2019 systematic review by Blazek and colleagues screened 1,125 studies and kept 16 that measured pressure inside the abdomen (intra-abdominal pressure) and chest (intrathoracic pressure) during hard resistance exercise. Squats produced the highest abdominal pressures, above 200 mmHg. Deadlifts, slide rows and leg presses landed between 161 and 176 mmHg. The bench press was lowest at 79 mmHg, with a standard deviation of 44 mmHg. Pressure depended on body position and on the external load.
Does your breathing technique change the lift?
In a 2021 study, 24 healthy men performed a one-repetition-maximum (1RM) bench press under four breathing techniques: Valsalva, simple breath-holding, lung packing (taking extra gulps of air on top of a full breath) and reverse breathing (exhaling during the lowering phase and inhaling on the press) (Blazek et al., 2021).
Reverse breathing lowered the load the men could lift. Valsalva shortened the concentric phase, the pushing part of the rep, compared with the other techniques. Simple breath-holding did not cost much load, but it lengthened the lift and the time spent in the sticking region, the hardest point of the rep. The authors concluded that Valsalva or lung packing can be chosen by preference, and they advised against reverse breathing for 1RM attempts.
So for a true max, a braced hold seems to serve strength. That says nothing about what the same hold does to the rest of your body.
What it does to blood pressure
A 2023 study by Drury and Green asked 14 people, 8 powerlifters and 6 controls, to hold four 15-second Valsalva efforts at 30 percent and at 50 percent of their maximum expiratory pressure. Pushing harder meant bigger swings. During the manoeuvre's second phase, heart rate rose by 39.9 beats per minute at 50 percent against 24.5 at 30 percent, and systolic blood pressure rose by 43.6 against 35.3 mmHg. Powerlifters showed larger responses than controls, which the authors linked to their higher expiratory pressures.
The effect also reaches the vessels. In 2015, Mak and Lai had 18 healthy young men do biceps curls with a Valsalva during each contraction. Carotid pulse wave velocity, a measure of how stiff the large neck arteries are, rose from 4.67 to 4.91 m/s right after exercise and was back at 4.66 m/s fifteen minutes later. A 2007 study by Heffernan and colleagues with 14 men found a similar direction: repeated Valsalva manoeuvres raised central pulse wave velocity from 7.1 to 7.8 m/s, while a resistance exercise bout with comparable blood pressure swings left it at 7.2 m/s.
A 2021 narrative review by Perry and Lucas adds the brain to the picture. The Valsalva manoeuvre affects how cerebral blood flow is regulated, and resistance exercise can lead to adverse events such as syncope, meaning fainting.
The honest limit
The samples are small: 5, 14, 18 and 24 people. Nearly all participants were young, healthy men, and most protocols were single laboratory sessions. The stiffness changes lasted minutes in the study that followed them. None of the primary studies tracked injuries over months or years, so they cannot say whether habitual bracing harms a healthy lifter.
The two arterial stiffness studies are also hard to line up. They used different exercises, different muscles and different comparison conditions, and the second one found no change after the exercise bout itself. And none of this data covers people with high blood pressure, heart disease or eye conditions. For them, the numbers above are a reason to talk to a doctor, not a green light.
The 2019 review authors also draw a practical line from their pressure data. They suggest the bench press and the slide row for beginners and for people with high blood pressure, and they advise untrained people to avoid heavy squats, deadlifts, box lifts and cleans until they have adapted to high loads. That is the reviewers' recommendation, not a tested training protocol.
How to use it in the gym
Pressure depends on load and lift, so match your breathing to the set. On light warm-up sets there is little reason to hold anything, and you can simply keep breathing.
On heavy sets, if you brace, keep the hold short. Take your air before the hardest part of the rep and let it out once you are past it. Holding through a whole high-rep set is the situation where pressure keeps repeating without any lifting benefit.
Skip reverse breathing on maximal attempts, since it lowered 1RM load in the bench press study.
Stop the set if you feel dizzy, see spots or get a pounding headache, and ask a doctor before heavy lifting if you have high blood pressure or a heart condition. If you also train endurance, this fits with the idea that breathing routes and rhythm matter for different jobs, as in our piece on controlled nasal breathing for athletes and the basics in why mouth breathing is bad for your health.
FAQ
Should I exhale on the way up?
Many gym guides say so, but the studies above did not test it for moderate loads. For a heavy single, the bench press trial favoured Valsalva or lung packing over reverse breathing. For lighter sets, exhaling through the hard part is a reasonable habit that keeps pressure lower.
Is the Valsalva manoeuvre dangerous?
It raises blood pressure sharply for a few seconds, and larger efforts raise it more. In healthy young lifters the studied vessel changes were temporary. Whether that holds for people with cardiovascular conditions is not answered by these papers.
Breathing decisions under a bar come down to one trade: more pressure for more stability, paid for in blood pressure swings. Use it on the heavy part of the heavy set and breathe normally the rest of the time. This article is general information and no medical advice. If you have lasting symptoms such as dizziness or chest discomfort during training, have them checked by a doctor.
Sources
- MacDougall JD, Tuxen D, Sale DG, Moroz JR, Sutton JR (1985). Arterial blood pressure response to heavy resistance exercise. Journal of Applied Physiology 58(3):785-790. doi.org/10.1152/jappl.1985.58.3.785
- Blazek D, Stastny P, Maszczyk A, Krawczyk M, Matykiewicz P, Petr M (2019). Systematic review of intra-abdominal and intrathoracic pressures initiated by the Valsalva manoeuvre during high-intensity resistance exercises. Biology of Sport 36(4):373-386. doi.org/10.5114/biolsport.2019.88759
- Blazek D, Kolinger D, Petruzela J, Kubovy P, Golas A, Petr M, Pisz A, Stastny P (2021). The effect of breathing technique on sticking region during maximal bench press. Biology of Sport 38(3):445-450. doi.org/10.5114/biolsport.2021.100362
- Drury K, Green S (2023). Effects of intensity and training on cardiovascular responses to the Valsalva manoeuvre. Journal of Basic and Clinical Physiology and Pharmacology 34(1):111-119. doi.org/10.1515/jbcpp-2022-0029
- Mak WYV, Lai WKC (2015). Acute effect on arterial stiffness after performing resistance exercise by using the Valsalva manoeuvre during exertion. BioMed Research International 2015:343916. doi.org/10.1155/2015/343916
- Heffernan KS, Jae SY, Edwards DG, Kelly EE, Fernhall B (2007). Arterial stiffness following repeated Valsalva maneuvers and resistance exercise in young men. Applied Physiology, Nutrition, and Metabolism 32(2):257-264. doi.org/10.1139/H06-107
- Perry BG, Lucas SJE (2021). The acute cardiorespiratory and cerebrovascular response to resistance exercise. Sports Medicine - Open 7:36. doi.org/10.1186/s40798-021-00314-w