How Diaphragmatic Breathing Boosts Your Lifts, Cardio and Stress Levels After 40.
You take somewhere between 17,000 and 23,000 breaths every day. It happens automatically, without any conscious input, which is both a marvel of human biology and the reason most people never think about it. But here’s the thing — just because breathing is automatic doesn’t mean it’s optimal. And for people over 40 who want to train harder, recover faster, manage stress better and get more out of every session, learning to breathe properly is one of the highest-return skills available.
This isn’t a niche topic for yogis or meditation enthusiasts. The way you breathe affects your intra-abdominal pressure during a heavy lift, your oxygen efficiency during cardio, the tension you carry through your neck and shoulders, and the state of your nervous system throughout the day. It influences your performance, your recovery and your resilience to stress — all things that become increasingly important as you move through your forties and beyond.
The good news is that diaphragmatic breathing — breathing that uses the diaphragm properly rather than relying on the chest and accessory muscles — can be learned relatively quickly, applied immediately, and felt within sessions almost straight away. It’s one of those rare things in health and fitness where the learning curve is short and the benefits are genuinely broad.
What diaphragmatic breathing actually is
The diaphragm is a large, dome-shaped muscle that sits beneath your lungs, separating the chest cavity from the abdominal cavity. When you inhale, the diaphragm contracts and flattens downward, creating a pressure change that draws air into the lungs. As it descends, it pushes gently on the abdominal contents, causing the belly to rise outward. When you exhale, the diaphragm relaxes and rises back to its domed position, pushing air out of the lungs.
This is how breathing is designed to work. But for a large proportion of adults — particularly those who sit for long periods, carry chronic stress, or have spent years sucking in their stomach for aesthetic reasons — the diaphragm has been partially replaced by the accessory muscles of the chest, neck and shoulders as the primary drivers of breathing. The result is a shallow, chest-dominant breathing pattern that uses more muscular effort, moves less air per breath, keeps the nervous system in a subtly elevated state of arousal, and contributes to the chronic neck and shoulder tension that so many desk workers and over-40s carry as a default.
A simple self-test: sit or lie comfortably and take a normal breath. Does your chest rise first, or your belly? If it’s your chest, you’re breathing predominantly with your accessory muscles rather than your diaphragm. If your belly rises first and your chest follows gently, your diaphragm is doing its job.
Why breathing changes after 40
Several factors conspire to shift breathing patterns as we age, and understanding them makes the solution feel more intuitive.
Posture is one of the biggest contributors. The thoracic rounding and forward head position that develops from years of desk work and sedentary habits physically compresses the chest cavity and limits the diaphragm’s ability to descend fully during inhalation. A rounded upper back is not just an aesthetic concern — it mechanically disadvantages one of the most important muscles in your body.
Stress accumulation is another major factor. Chronic stress keeps the autonomic nervous system running in a state of low-level sympathetic activation — the fight-or-flight mode. One of the hallmarks of sympathetic dominance is faster, shallower, chest-based breathing, which both reflects and reinforces the stressed state. After years of this pattern, it can become the default even in situations that don’t call for it.
Core dysfunction also plays a role. The diaphragm is not only a breathing muscle — it is a core stability muscle, working in coordination with the pelvic floor, the deep abdominal muscles and the spinal stabilisers to manage intra-abdominal pressure. When this system isn’t functioning well, the body often defaults to bracing patterns that restrict diaphragmatic movement in an attempt to compensate for missing stability.
Breathing and lifting: the intra-abdominal pressure connection
If you’ve ever heard a powerlifter talk about bracing before a big lift, you’ve heard references to intra-abdominal pressure — though perhaps not by that name. This concept is one of the most important and least understood aspects of safe, effective strength training, and diaphragmatic breathing is central to it.
Intra-abdominal pressure is the pressure generated inside the abdominal cavity when the muscles surrounding it — including the diaphragm above, the pelvic floor below, and the deep abdominals around the sides — contract together around a held breath. When properly generated, this pressure creates a rigid column of support around the spine, protecting it from the compressive and shear forces that occur during heavy lifting. It is essentially your body’s internal weight belt, and it is vastly more effective than any external support when it’s working properly.
The sequence matters enormously. Before a heavy squat, deadlift, press or any loaded spinal movement, the correct preparation involves taking a deep diaphragmatic breath in — filling the belly, creating 360 degrees of expansion around the trunk — and then bracing the entire midsection firmly around that breath before the movement begins. This is called the Valsalva manoeuvre, and when done correctly it creates the intra-abdominal pressure that protects the spine and allows maximal force production.
Many people do the opposite — they exhale and then try to brace, or they brace without breathing first, or they breathe shallowly into the chest which doesn’t create sufficient pressure in the abdominal cavity. The result is a compromised brace that offers less spinal protection and limits how much force the body can generate through the movement.
For people over 40 whose spinal health is an increasing priority, learning to generate proper intra-abdominal pressure through diaphragmatic breathing before each significant lift is not optional — it is foundational. An Exercise Physiologist can teach this in a single session and the improvement in both safety and performance is often immediately noticeable.
One important nuance: the full Valsalva manoeuvre — a hard breath hold during maximal effort — is appropriate for healthy individuals performing heavy resistance training but should be used thoughtfully by anyone with existing cardiovascular conditions or very high blood pressure. An Exercise Physiologist will advise on the appropriate version of this technique for your individual health situation.
Breathing and cardio: efficiency, not just effort
The relationship between breathing and cardiovascular performance is equally significant, though it plays out differently. In cardio training, the goal isn’t to hold your breath — it’s to breathe as efficiently as possible so that the respiratory muscles themselves don’t become a limiting factor in your performance.
Most recreational exercisers breathe with a chest-dominant pattern during cardio as well, which is inefficient for several reasons. Chest breathing moves less air per breath than diaphragmatic breathing, meaning more breaths are required to achieve the same oxygen delivery. This increases the work of breathing — the energy cost of the breathing process itself — which competes with the muscles doing the actual exercise for available oxygen. It also tends to promote a faster, more chaotic breathing rhythm that can accelerate the onset of breathlessness and make sustained aerobic effort feel harder than it needs to.
Diaphragmatic breathing during cardio allows for fuller, more efficient breaths — more oxygen in and more carbon dioxide out per breath — which reduces breathing rate, lowers the work of breathing, and frees up more oxygen for the working muscles. For runners, cyclists and swimmers in particular, developing a relaxed diaphragmatic breathing pattern can meaningfully extend the pace that feels comfortable before breathlessness sets in.
Nasal breathing during lower-intensity cardio is worth exploring in this context. Breathing in through the nose rather than the mouth naturally slows the breath, warms and filters the air, and encourages diaphragmatic rather than chest breathing. Nitric oxide — a vasodilator that improves oxygen delivery to tissues — is also produced in the nasal passages and delivered to the lungs with nasal inhalation. Many experienced endurance athletes use nasal-only breathing during easy and moderate efforts as a training tool to develop respiratory efficiency, switching to mouth breathing only when intensity demands it.
For people over 40 returning to cardio after a break, learning to breathe efficiently can make the difference between a run that feels unmanageable and one that feels controlled and enjoyable — not because the cardiovascular system has suddenly improved, but because the respiratory system is no longer fighting against itself.
Breathing and stress: the nervous system connection
Of all the applications of diaphragmatic breathing, its effect on the nervous system may be the most immediately powerful — and certainly the most broadly applicable to daily life beyond the gym.
The autonomic nervous system has two primary modes: the sympathetic mode, associated with arousal, stress and the fight-or-flight response, and the parasympathetic mode, associated with calm, recovery and the rest-and-digest response. These two modes are not fully voluntary — you can’t simply decide to switch from one to the other. But breathing is one of the very few physiological processes that sits at the interface between voluntary and involuntary control, which means it provides a rare direct lever on the autonomic nervous system.
Slow, deep, diaphragmatic breathing — particularly when the exhale is longer than the inhale — activates the vagus nerve, the primary nerve of the parasympathetic system, and produces a measurable shift toward parasympathetic dominance. Heart rate slows. Blood pressure drops. Cortisol levels begin to fall. Muscle tension reduces. Digestive function improves. The body shifts, quite literally, from a state of threat response toward a state of recovery and calm.
For people over 40 managing the stressors of careers, family, finances and the health challenges that tend to accumulate through middle age, this is not a small thing. Chronic sympathetic dominance — the state of being perpetually slightly stressed — is associated with elevated cortisol, disrupted sleep, impaired recovery from exercise, increased cardiovascular risk, and a general sense of being perpetually wound up that is both exhausting and difficult to shift.
A simple breathing practice done deliberately for even five to ten minutes a day can produce meaningful reductions in baseline stress and cortisol over time. The physiological effect is real, measurable, and well-supported by research. It requires no equipment, no medication and no gym membership — just the willingness to pay attention to something you’re already doing thousands of times a day.
Practical breathing techniques to start using now
Box breathing is one of the most effective and accessible stress-management techniques available. Inhale for four counts, hold for four counts, exhale for four counts, hold for four counts, and repeat. The equal timing creates a balanced, rhythmic breath pattern that engages the vagus nerve and shifts the nervous system toward calm. It is used by military personnel, athletes and clinicians for exactly this reason, and it works within minutes. A session of five to ten rounds is enough to produce a noticeable effect.
Physiological sigh — two quick inhales through the nose followed by a long, slow exhale through the mouth — is one of the fastest ways to offload acute stress. The double inhale pops open any partially collapsed air sacs in the lungs, maximising the gas exchange that drives the following exhale. The long exhale then activates the parasympathetic system powerfully. It sounds almost too simple, but the research behind it is strong and the effect is immediate.
Diaphragmatic breathing practice can be done lying on your back with one hand on your chest and one on your belly. The goal is to breathe so that the belly hand rises and the chest hand stays relatively still. Spend five minutes on this daily for two weeks and the pattern will begin to carry over into your resting breathing and eventually into training.
Pre-lift breathing, as described above, involves taking a full diaphragmatic breath before any significant loaded movement, bracing the entire midsection around that breath, completing the movement, and exhaling on the way back to the start position or between reps depending on the exercise and load. An Exercise Physiologist can coach this precisely and ensure the technique is appropriate for your training.
How an Exercise Physiologist brings it all together
Breathing technique is one of those areas where knowing the theory and actually applying it correctly during a heavy squat or a hard interval are two quite different things. The patterns that have been established over years of habitual chest breathing don’t change overnight, and the tendency to revert under load — when the nervous system is demanding oxygen and effort is high — is strong.
An Exercise Physiologist can assess your current breathing pattern, identify where the compensations are occurring, and teach the correct technique in the context of the movements you actually do. They can cue you during lifts until the new pattern becomes automatic, monitor your breathing rhythm during cardio and help you find the pace at which efficient diaphragmatic breathing is sustainable, and design a brief daily breathing practice tailored to your stress levels and recovery needs.
For people with any pelvic floor considerations, core dysfunction, or existing respiratory conditions, breathing technique takes on additional clinical significance — and the guidance of a professional becomes even more valuable.
At Inspire Fitness in Balwyn North, breathing is something we weave into every aspect of the programs we design. It’s not an add-on or an afterthought — it’s a foundation. Because when you breathe well, everything else works better.