Breast anatomy
The breast is made up of three major components:
- Connective (fibrous) tissue
- Glandular (mammary) tissue
- Adipose (fat) tissue
The breast contains no muscle or bone, it is a unique soft tissue which has very poor internal support.
Individuals vary considerably in terms of the size, contour, and density of their breasts at maturity.
- Chest wall: The ribs are the foundation for the breasts to sit on.
- Pectoralis muscles: The breast lies on the Pectoralis major muscle, and usually extends from the 2nd to the 6th rib.
- Lobules: The breast is made up of sections called lobes and each lobe is made up of smaller lobules, which are the glands that produces milk in nursing women. These make up the functional aspect of the breast.
- Nipple surface: Milk exits the breast at the nipple, which is surrounded by a darkened area of skin called the areola.
- Areola: The areola contains small, modified sweat glands known as Montgomery's glands. These glands secrete fluid that serves to lubricate the nipple during breastfeeding.
- Milk ducts: Both the lobes and lobules are connected by milk ducts, which act as tubes to carry the milk to the nipple.
- Fatty/adipose tissue: The female breast is mostly made up of a collection of fat cells called adipose tissue. This tissue extends from the collarbone down to the underarm and across to the middle of the ribcage. Within the adipose tissue is a network of ligaments, fibrous connective tissue, nerves, lymph vessels, lymph nodes, and blood vessels. Cooper’s ligaments are connective tissue in the breast that help to maintain its structural integrity and are thought to provide some support to the breast.
- Skin: Thought to be the main supporting structure of the breast
Breast changes during the life cycle
Menopause and ageing
Glandular tissue in the breast is supported by oestrogen, meaning that during menopause and beyond there is a natural atrophy of this tissue. There is a decline in breast skin elasticity and thickness from a woman's mid-20’s, women may therefore benefit from a more supportive bra with increasing age.
Weight changes
Fatty tissue in the breasts will respond to systematic weight gain and weight loss. It is important to reassess your bra fit if you have recently gained or lost significant body weight.
Pregnancy and breastfeeding
Physical changes that the body experiences during pregnancy mean that the tissues attached to the breast are stretched even more, particularly during breastfeeding. Pregnant women undergo an increase in breast mass of one cup size or more, therefore frequent bra fits and appropriate breast support during pregnancy and breastfeeding is important to reduce breast pain and discomfort associated with breast changes.
Menstrual cycle
The menstrual cycle affects breast size and tenderness. For some women there is a significant increase in breast size just prior to menstruation (as much as one cup size) which may require a change in bra. A more supportive bra may be necessary when breasts are more painful.
Breast pain (mastalgia)
Pain is one of the most frequent breast symptoms experienced by women.
There are 3 main types of breast pain:
- Cyclical breast pain: varies in its presentation, severity and relationship to the menstrual cycle.
- Non-cyclical: persistent or intermittent pain not linked to the menstrual cycle.
- Exercise-induced breast pain: this is a more recent term used to describe breast pain that is caused by breast movement when exercising due to the breast’s limited internal support.
Interestingly the exact cause of breast pain is unknown. There is certainly a link between breast movement and breast pain, and therefore firm breast support is recommended to reduce breast pain during exercise. Firm breast support is also recommended for women who experience severe cyclic and noncyclic breast pain, as this can reduce pain without the need for drugs that can cause undesirable side-effects. In breast pain research it was found that within the general population women who were older, larger-breasted and less active experienced more breast pain.
Recreational and elite athletes also report experiencing breast pain which can affect their performance and ability to put 100% into training or competition. A well-fitted and supportive sports bra can help to relieve symptoms of breast pain for women of all breast sizes.
Breast sag (ptosis)
When a female ages her breasts will naturally lose their elasticity and due to the force of gravity will eventually become more ptotic (ie, sag more). It has been proposed that repeated loading of the supporting structures of the breast (Cooper’s ligaments and skin) due to excessive breast movement may lead to irreparable damage of these structures. This stretching is thought to result in breast sag; hence the use of a supporting bra during exercise has been promoted. During running, the strain on the breast skin can be excessive, especially for larger breast volumes. Lift is required in the bra cup (especially at the sides) to help reduce this strain.
A sports bra providing extra support can alleviate anxiety for those who are concerned that high impact exercise may contribute to breast sagging. However, it is unknown how detrimental excessive breast movement is on delicate breast tissue in the long-term.
Breast size
It is difficult to get reliable data on bra size as this is generally self-reported or based on bra sales, when ~80% of females may be wearing the wrong bra size. However, it is evident that bust circumferences are increasing globally and ~35% of women have either large (breast volume, 700-1200mL) or hypertrophic (breast volume, >1200mL) breasts.
The most common self-reported bra size by police officers was a 34B, although there was a large range of sizes reported. Female police officers with larger breasts have reported more issues with rubbing / discomfort, which could be related to a lack of breast support for larger breasts, or poor fitting of body armour.
It is simple physics - Force = mass x acceleration. Therefore as breast mass increases, the forces created when the breast moves during exercise are increased, which can lead to an increase in breast pain.
There are many negative effects of having larger breasts (cup size D and above)
Breasts as a barrier to exercise
The breast can be a barrier to exercise for women. In one study within the general population it was found that 17% of women aged 18 to 65 years felt their breasts were a barrier to physical activity participation. The most popular responses were: “I can’t find the right sports bra”, “I am embarrassed by excessive breast movement” and “My breasts are too big”. The breast was the 4th highest barrier reported, above cost and facilities!