Infertility, Hormone Changes in Women and Breathing

HORMONE CHANGES IN WOMEN AND BREATHING

Men and women do breathe differently! Women tend to suffer from more breathing pattern disorders (BPD) than men¹. Unfortunately the effects of BPD (also known as dysfunctional breathing) are still under- recognized by health care professionals, however they play an important role in contributing to fatigue, pain, poor sleep and changes to enzyme and hormone synthesis for example.

Hyperventilation plays a big part in BPD and is defined as breathing more than the body needs for normal metabolic requirements to remain stable (in homeostasis). It leads to a marked drop in partial pressure of arterial carbon dioxide (PaCO2) and a range of consequent physiologic changes such as poor oxygen delivery, vaso- and broncho-constriction (read more in the Article on Chronic Hyperventilation).

Back as far as 1905, it was discovered that the resting pressure of arterial (blood) carbon dioxide was about 8% lower in woman than in men1; and that airflow and gas exchange alter during the menstrual cycle².

Women breathe less than men on average as a result, in part, because of a smaller frame and airways, and a shorter diaphragm (by about 9%)3, however a woman’s ventilation volume and rate also varies with her menstrual cycle in response to hormonal changes and the same is true during pregnancy and menopause changes?

Up until recently most medication trials and methods have centred on testing males only – animal and human, and often have not taken into account the time of month nor hormonal changes that occur throughout much of a woman’s life ^{1, 4}.

There is now a move to do more studies on women however there are some things we know already that can be helpful. For example some current research suggests that ensuring healthy breathing – nasal, regular, slow and gentle breathing – can help to minimize the symptoms of premenstrual syndrome (PMS).

Progesterone, which is produced during the time between ovulation and menstruation (the luteal phase), and also during pregnancy, has been found to stimulate breathing. As a result, CO2 levels drop by around 25%. If levels become hypocapnic (lower than healthy arterial CO2 levels), the respiratory centre in the brain will register stress and cause the breathing rate to increase even more which can create a range of symptoms which often get called PMS (Premenstrual Syndrome)^5,6.

The follicular phase of the menstrual cycle is when the body is prepping for ovulation and is measured from the first day of your period until ovulation. This is the time that oestrogen production is increasing.

From the mid-follicular phase to the mid luteal phase (at between 10 and about 22 days), breathing issues such as wheeziness, breathlessness, congestion and coughing, often worsen ^{7, 8}.

In general, body temperature also affects the breathing rate. Just as progesterone levels increase during the luteal phase so too does body temperature and, in combination, will account for some changes to breathing after mid cycle such as an increase in breathing rate.

An interesting study in 2008 indicated that at times when progesterone increases, and breathing ramps up in volume and speed; pain thresh-holds drop⁹. This means that you feel pain more readily or intensely even when the pain stimulus is less intense than you would normally feel the same level of pain.

Unfortunately pain and dysfunction in general also contribute to changes to breathing rates, and so help “to create a reciprocally negative series of adaptations in which pain alters respiration, which in turn amplifies pain”¹⁰.

Menstruation has been linked to iron deficiency and aneamia which could suggest why it has been shown to impair cognitive and immune system function and even cause problems during pregnancy in nulliparous women (a woman who has not yet had a baby)¹¹.

Where breathing may tie into this, is that iron deficiency generally causes the breathing rate to increase. If a woman is already even mildly hypocapnic at baseline (see article on hyperventilation and hypocapnia) because of a faster than healthy breathing rate, then iron deficiency would reduce efficient oxygen delivery even further, impacting on health in general such as cardiovascular and cognitive function, and the immune system.

During pregnancy the breathing rate ramps up naturally so if a woman’s breathing rate pre-conception is already faster than functional, whether due to dysfunctional breathing or iron deficiency for example, then her increased breathing rate will likely have an even greater impact on her own and her baby’s health.

It makes sense therefore that breathing well is likely to be beneficial in moderating hormone changes in women and in helping to prevent BPD and to reduce symptoms of PMS.