Walk into almost any commercial gym at peak hours, and you\u2019ll hear it: a sudden guttural grunt slicing through the hum of treadmills and clanking plates. Sometimes it accompanies a heavy deadlift or chest press. Othertimes, a pec deck set that barely warrants a raised eyebrow, let alone a primal yell.<\/p>\n
So, when is it OK to grunt, and is it fair that you are annoyed by hearing others do it? According to James Nestor,<\/a> New York Times bestselling author of Breath<\/a> and one of the leading voices in modern breathing science, the answer has less to do with gym etiquette and more with pressure, physiology, and control.<\/p>\n \u201cGrunting can help only when it\u2019s an accidental byproduct of good breathing,\u201d Nestor explained to Muscle & Fitness.<\/em><\/p>\n That distinction between accident versus intention may be the clearest line between performance breathing and what Nestor calls performative breathing.<\/p>\n At the center of the debate, Nestor explains, is intra-abdominal pressure. Heavy lifting demands a stable, pressurized torso that protects the spine and allows force to transfer efficiently.<\/p>\n The diaphragm, an umbrella-shaped muscle beneath the lungs, plays a starring role. When it contracts, it descends, the abdomen expands, and pressure builds around the torso like an inflated column. In layman\u2019s terms, it\u2019s often called belly breathing.<\/p>\n \u201cWhen this pressure is released slowly through the airway, a sound may occur, one might call a grunt,\u201d Nestor explains. \u201cGrunting is not the goal, but rather the aftereffect of pressure release.\u201d<\/p>\n He further noted that decades of sports science research examining breath control<\/a> during force production show that brief airway closure or resistance, including techniques similar to the Valsalva maneuver or controlled forceful exhalation, can increase maximal force output, often in the range of 2-10%, depending on the task. Improvements have been documented in measures such as grip strength, isometric force, and explosive power output.<\/p>\n \u201cThis isn\u2019t because the sound is loud, but because briefly closing the airway (the glottis) increases pressure inside the torso, which ramps up the ability of muscles to fire harder and more efficiently,\u201d he notes, adding that when the grunt becomes theatrical, something breaks down.<\/p>\n \u201cThe moment a grunt becomes intentional, it\u2019s usually a sign that the diaphragm is no longer engaged,\u201d Nestor says. \u201cBreathing shifts upward into the neck, jaw, and face, muscles that were never meant to stabilize heavy loads.\u201d<\/p>\n One of the most persistent myths in gym culture is that louder breathing signals greater power. According to Nestor, physiologically, that\u2019s nonsense.<\/p>\n \u201cThere is zero evidence that increasing the volume of a grunt yields more endurance,\u201d Nestor says, noting that studies examining breathing strategies during resistance exercise consistently show that coordination and timing matter far more than sound intensity.<\/p>\n He explains that a \u201cfunctional grunt,\u201d or a short, controlled, conscious yelp, however, may be useful. From a mechanical standpoint, that\u2019s the body\u2019s response to airway resistance. Narrowing the vocal cords during exhalation increases resistance, helping maintain lung inflation and torso stability, similar to pursed-lip breathing used in pulmonary rehabilitation. The effect is comparable to air slowly leaking from a tire rather than rushing out all at once.<\/p>\n \u201cThe body doesn\u2019t care about sound. It cares about controlling pressure,\u201d Nestor says, adding that sound is merely a byproduct. When sound comes from throat tension instead of controlled diaphragm engagement, pressure dissipates rapidly, which may result in less stability.<\/p>\n Another gym myth is that breathlessness or gasping for air is a sign of a lack of oxygen. According to Nestor, not quite.<\/p>\n \u201cYou almost never run out of oxygen,\u201d Nestor says. \u201cWhat breaks down performance is rising carbon dioxide.\u201d<\/p>\n Rising CO\u2082 levels stimulate chemoreceptors that trigger an emergency signal in the brain to breathe, shifting the nervous system\u2019s priority from performance to survival. Initially, your brain is telling your body to stop focusing on lifting the weight and just breathe instead. According to Nestor, that\u2019s why elite athletes train specifically to tolerate higher CO\u2082 levels.<\/p>\n \u201cThe more carbon dioxide your body can comfortably tolerate, the more oxygen you will get to your hungry cells, and the longer and stronger you\u2019ll be able to perform,\u201d he says, noting that many of the noises you might hear in the gym, like forced exhales, moans, and grunts, are the result of the body reaching the limit of carbon dioxide tolerance and the brain putting on the emergency break.<\/p>\n Hence, grunting should support the lift, not show it off. \u201cIf you\u2019re grunting during warmups, every rep, or whenever people are close, you have an issue, physical or psychological,\u201d Nestor points out, adding that grunting through pain might signal poor load management and breathing mechanics.<\/p>\n How you breathe should change based on your training program, the load you\u2019re moving, and the physiological demand being placed on your body. Here\u2019s how Nestor breaks down how you should breathe based on your workouts:<\/p>\n Maximal lifts:<\/strong> The priority is pressure and timing. Heavy loads need high internal pressure at the correct time to keep the spine stabilized. This can occur either through a short-term breath hold or through a \u201cleak\u201d exhalation that is timed and deliberate.<\/p>\n Rep work, like AMRAP:<\/strong> The main focus is to complete the greatest number of reps possible during a set time window. This requires a consistent breathing pattern that stays organized and rhythmic while maintaining pressure without leading to panic. Breathing excessively or holding your breath dramatically will often cut the number of sets you complete and limit the total volume.<\/p>\n Endurance and conditioning:<\/strong> Priorities shift to efficient ventilation and the ability to tolerate carbon dioxide. He points to nasal breathing here as it slows down your breathing and makes it more efficient. Plus, it also promotes the release of nitric oxide, which allows your body to go longer and harder without breaking down.<\/p>\n Nestor underscores that studies have shown that when recreational athletes train to use nasal breathing, they are able to reach up to 85% of their maximum oxygen uptake (VO2max<\/a>) for intense periods of exercise.<\/p>\n \u201cThey are often able to achieve the same peak performance and oxygen consumption as when they used mouth breathing; however, they breathed approximately more than 20% less volume during the time,\u201d he explains, adding that the same output for less effort means you can be stronger for longer. But there is a time and place for everything. In upper Zone 4 and Zone 5 training, consciously switching to mouth breathing for short bursts can instill benefits.<\/p>\n Before you roll your eyes the next time you hear someone across the gym grunting mid-set, it\u2019s worth considering what that sound might represent. In some cases, it reflects a controlled release of pressure during a demanding effort. In others, it signals a breakdown in breathing mechanics, load management, or nervous system regulation. Don\u2019t be the latter. The difference matters.<\/p>\n \u201cThe body doesn\u2019t care about how twisted your face is or the timbre of your voice,\u201d Nestor said. \u201cIt only cares about how to generate pressure efficiently, keep the nervous system stable, and support all the mechanisms of the body.\u201d<\/p>\n<\/p><\/div>\nThe Role of Intra-Abdominal Pressure in Heavy Lifting<\/h2>\n
Does Grunting Increase Strength and Power?<\/h2>\n
![\"Fit](\"https:\/\/i0.wp.com\/www.muscleandfitness.com\/wp-content\/uploads\/2026\/02\/Fit-older-male-breathing-and-grunting-during-a-difficult-workout-using-dumbbell-rows.jpg?quality=86&strip=all\")
<\/div>What Happens When You\u2019re Gasping for Air During a Workout?<\/h2>\n
How to Breathe Properly During Heavy Lifts<\/h2>\n
When It\u2019s OK to Grunt in the Gym<\/h2>\n