Lately I’ve noticed something about breasts.
More specifically, what women choose to wear and support them. Bras.
I noticed there is a perceptible difference between how I breathe while wearing a bra and while not.
Without a bra, I feel my breaths can be full and free. With a bra, especially a sports bra: not so much.
Curious, I started asking other women “Do you think that wearing a sports bra impacts your breathing?”
After a moment of consideration, the majority responded with a definite, “YES.” Given the resounding affirmation, I started to dig, wondering if there was anything beyond anecdotal evidence.
I searched PubMed for scientific research on the impact that bras have on breathing and was surprised to find only a single article.
This single investigation found no significant difference in measured lung volumes between bra and no bra conditions while performing sub-maximal treadmill exercise or maximal bicycling.
I won't nit pic the details of the study, but until science does more to disprove that sports bras affect breathing, the paucity of evidence encourages us to ask better questions and hypothesize on what might occur.
Below I have outlined questions I have and an educated guess on why and how respiration might be influenced by wearing a sports bra.
We start by looking at ways breathing is assessed.
1) Respiratory kinematics – the mechanics of the musculoskeletal system
2) Pulmonary function tests - the amount of respiratory impairment
3) Subjective – observations by the individual
Do sports bras affect breathing patterns – how the thorax and muscles work to move air?
Breathing is a movement behavior and respiratory kinematics can be broken down into 2 phases: inhalation and exhalation. During these phases we can simplify the mechanics of respiration by these descriptions:
Inhalation = active thorax expansion
Exhalation = passive (or active) reduction of that expansion
Sports bras vary in design and fit, providing a range of external pressures on the ribcage. Is this enough to affect our capacity to expand the thorax upon inhalation?
The adaptations of a thorax made over a lifetime are highly individual making a study on ribcage mechanics tough. But we can still wonder. I wonder if a sports bra, because its supportive band encircles the caudal end of the ribcage, restricts bucket handle movement of the ribs?
less bucket, more pump?
For breathing to be economical the breath pattern must adapt to the mechanical properties of the respiratory system. Resisted expansion of the thorax from compressive forces may cause the muscles of inspiration to work harder or differently.
Pulmonary Function Tests
Do sports bras affect the amount of air we can inhale or exhale at rest or with exercise?
There are many components to respiratory physiology. Pulmonary function tests, such as spirometry, lung volume tests, pulse oximetry and arterial blood gas tests help quantify lung function.
The most common and practical of the measures is ‘volume of air’.
In several attempts to model the effect of restrictive respiratory disorders, chest-wall strapping has been used to simulate restricted thorax expansion. These studies verify that the mechanical restriction of the chest induces breathing at low volumes. (2)
In restrictive lung conditions the adaptation to decreased tidal volume is often an increased respiratory rate. Perhaps this happens to a smaller degree with sports bras in some individuals.
Comparing elastic sports bras to inelastic chest strapping or restrictive lung disorders helps us propose a potential effect. We need more studies.
Does the compression from a sports bra change how breathing feels?
Perhaps more than mechanics and measures of ventilation, the effect of bras may be one of perception.
The experience of dyspnea occurs in various cardiopulmonary and musculoskeletal disorders that mechanically restrict inhalation. Exertional dyspnea is common with exercise. Described with various terms like "effortful", difficult" or "uncomfortable" dyspnea, like pain, is a stress output- highly individual and multifactorial. (3)
We “feel” breathing by processing sensory stimuli imparted by chemoreceptors and mechanoreceptors in the respiratory system, including the chest wall.
If mechanoreceptors detect a lack of expansion upon inhalation, they likely signal to the central control system that changes in motor recruitment are needed to complete the work of breathing. The perceived effort of muscles working harder to get the job done or the tightness in one's chest could feel uncomfortable. You might adjust to not feel the discomfort.
While there are several scales to measure dyspnea, simple tools like the Visual Analog Scale and the Modified Borg scale are easy to employ. (4)
We could speculate all day but you probably want to know.....
WHAT SHOULD WE DO?
1) Don’t demonize bras OR breathing
To be or not to be a bra wearer is an individual choice. Suggesting someone do their meditation or breathing-based exercises without a bra is different than declaring that their breathing will be screwed up if they wear one.
Perhaps we can simply ask: Do you feel constricted in your clothing? Do you feel better able to breathe and move freely without it? If yes, then they can make a choice.
2) Encourage the right fit
80% of women wear the wrong size of bra, and of those, 70% of women wear bras that are too small. (5)
A study in BJSM showed that respiratory state significantly affects bra size. (6) There is an average increase of one band size for chest circumferences during inhalation. Standardizing bra fitting to include respiratory state would be a positive step.
As movement practitioners we should encourage women to inhale and exhale while trying on bras/sports bras to ensure they feel comfortable.
It’s also important to remember that bra-fit may change with hormonal fluctuations and weight gain or loss. An optimal bra fit can help lower pain, raise exercise tolerance and even be associated with the ease of breathing.
3) Discuss Intention
The pros and cons of wearing sports bras will be highly individualized based on one’s body, sport and the intensity of activity.
An exercise designed to promote thorax expansion in a static position likely doesn’t require a sports bra for most. In this scenario, an environment that facilitates expansion, including loose fitting clothes, is ideal. Suggesting a patient performs a breathing-based exercise with, and then without, a bra on may help with many things including awareness.
On the other hand, most women will rely on the support and control of a sports bra for activities including, but definitely not limited to, running, boxing, or horseback riding.
Having a conversation about the intention of an exercise/activity or the intent of wearing a sports bra is a valuable venture.
4) Discuss the triple Ds
Donning, doffing and dosing.
Donning and Doffing are fancy terms for putting on and taking off. Dosing refers to the amount we participate in something and can be applied to how frequently or how long we wear sports bras.
If wearing a sports bra makes breathing uncomfortable or effortful suggest a restricted wearing time frame. Matching use to activity requirements and personal preference could lead to different daily choices.
Leisurewear, including sport bras, is commonplace nowadays. Many women wear sports bras all day long when they don’t necessarily need to.
My bias is that sports bras do affect breathing but recognize it lies on a spectrum, dependent on things like: bra-type and fit, body type, activity type, intensity, and other health factors.
Why does this question matter? Respiration is used in the rehab or fitness setting to facilitate a variety of gains.
Therapeutically to gain movement
Nasal breathing to promote upper airway patency and improve sleep
Resisted inspiratory training to enhance performance
Slow, deep breathing for relieving pain and stress
Breathing, like movement, should have variability. Whether you are going to take a deep breath in at rest or not, you should be able to.