Pregnancy is an Endurance Sport
Trends in Resting Heart Rate, HRV and Sleep
Neuro Athletes,
Happy Tuesday! I hope if you're reading this, you're feeling energised, and you have an Organifi drink in your hand.
If you aren’t part of the premium newsletter, you might want to check it out here. This weeks premium newsletter will be a recording of me answering Q&A’s that have come through on health, supplementation, brain performance and more…
Over the last week, I've been thinking more and more about this topic, which is: how does pregnancy disrupt sleep and why.
This came from a recent Twitter thread I was tagged in:
This area, in my opinion, hasn’t gotten much attention especially when it comes to sleep performance. I’m not sure why since so many physiological changes occur during pregnancy. Although some of these changes influence normal biochemical values, others mimic symptoms of medical disease 🤯
Among the many biochemical changes that takes place is that of sleep. However, little research has directly examined how sleep deprivation may affect maternal and fetal outcomes.
This newsletter highlights the important changes in sleep that take place during normal pregnancy.
If you were forwarded this newsletter, or you’re not a current subscriber, join 35,000+ individuals who subscribe to Neuro Athletics.
This email is brought to you by
I've been wearing a WHOOP for several years now, and it has made a massive difference in my life. It's the only tech product that I wear 24/7. So it's pretty cool to see people like Patrick Mahomes, Rory McIlroy, Michael Phelps, and Justin Beiber wearing one.
WHOOP automatically measures your respiratory rate, oxygen level, resting heart rate, heart rate variability, calories, and activity levels throughout the day. Sure, it might sound complex, but WHOOP interprets the data for you so it’s easy to digestible and actionable.
The best part?
No matter your wellness or performance goals, WHOOP’s mission is to help you live your healthiest life, and I can’t recommend it enough.
Try WHOOP’s new 4.0 for yourself and tell them I sent you.
Primer
Struggling to sleep well during pregnancy is not uncommon and for many women, sleep can be evasive during pregnancy. Physical discomfort, changing hormones, excitement and anxiety about being a new mother leads to a host of sleep problems. In fact, it’s believed that at least 50% of pregnant women suffer from insomnia.
A multitude of factors leads to insomnia during pregnancy. Beginning in the first trimester, fluctuating hormone levels cause generalized discomfort and other problems that can make it difficult to fall asleep and stay asleep.
Sleep Trends During Pregnancy
Sleep in women is affected by physiologic changes in neuroendocrine hormones, body temperature, mood, and emotional state during puberty, the menstrual cycle, pregnancy and menopause.
The hormonal and physical changes that occur during pregnancy are associated with altered sleep architecture as pregnancy progresses. While total sleep time increases marginally in the first trimester compared with the non-pregnant state, thereafter it progressively decreases and is significantly reduced during the third trimester.
During the first trimester, sleep increases (on average 7.4 to 8.2 h) and then decreases in the third trimester (6.6 to 7.8 h). One study showed that the rate of sleep disturbances also changes across trimesters, ranging from 13% in the first trimester, 19% in the second, and 66% in the third.
In the first trimester, the most common causes of poor sleep are nausea/vomiting, urinary frequency, and backache, while in the second and third trimesters the causes are fetal movements, heartburn, cramps or tingling in the legs, and shortness of breath.
Night waking is the most common sleep disturbance; by the end of pregnancy almost all women are waking up and for longer periods of time. The higher levels of estrogen and progesterone are thought to contribute to insomnia and they also influence other hormones such as the cortisol-melatonin ratio. Because progesterone and cortisol share binding sites on corticosteroid binding globulin, this leads to higher free cortisol which may increase arousal.
Respiratory Changes During Pregnancy
Once we fall asleep, the pace at which we breathe is determined by our metabolic rate. Most people breathe more slowly when they are asleep, and breathing evens out and becomes less variable with each successive stage of sleep. However, research shows that we also breathe faster and more erratically during the rapid eye movement (REM) sleep stage.
Many women report sleep disturbance during pregnancy, those with severe snoring, observed irregular breathing with sleep, or excessive daytime somnolence should be referred for clinical polysomnography. Pulmonary mechanics (measured during the day) are markedly altered during pregnancy, with a 20% reduction in functional residual capacity (FRC) arising from elevation of the diaphragm to accommodate the enlarging uterus.
Any condition that causes maternal hypoxemia will be worsened during sleep, particularly in the supine position. Although high circulating levels of progesterone increase respiratory drive during sleep, in at least some women this protective mechanism is insufficient to prevent sleep-disordered breathing and hypoxemia.
A number of physiological changes occur during normal pregnancy which may potentially compromise the respiratory system. Many of these changes are compounded during sleep due to a combination of both postural and sleep related phenomena. Related to these factors, the incidence of snoring is increased during pregnancy. While the true incidence of OSA during pregnancy is not yet known, recent studies by our group and others have shown that the severity of OSA is increased during pregnancy.
Hormonal changes associated with altered respiratory function during pregnancy
Circulating oestrogen and progesterone levels increase markedly during pregnancy, both primarily being responsible for maintaining the pregnancy. However, there are many other physiological changes produced by these hormones which are unrelated to maintenance of the pregnancy. Progesterone markedly upregulates ventilatory drive at the level of the central chemoreceptors.
The uterus and the hormonal effects produce anatomical changes to the thoracic cage. As the uterus expands, the diaphragm is displaced cephalad by as much as 4 cm; the anteroposterior and transverse diameter of the thorax increases, which enlarges chest wall circumference.
Sleep Disruption has Vast Health Consequences
What This Means for You
Women experience significant sleep disruption, inadequate sleep, and high rates of symptoms of sleep disorder throughout pregnancy. Pregnant women particularly need sufficient sleep to nourish the development of their infants and the energy they need for the labor and delivery process. Sleep deprivation during pregnancy has been associated with longer labor, elevated perception of pain and discomfort during labor, higher cesarean rates, preterm labor, and higher levels of pro-inflammatory serum cytokines.
In saying this, make sleep your best friend during pregnancy. Skipping out on sleep is going to happen but learning how to regulate your sleep-wake cycles and take control of your sleep stages is what is necessary for optimal sleep during pregnancy.
Until next time,
Louisa x
Product of The Week
VoxxLife combines the best of technology and wellness science to help you achieve your wellness goals, drug-free and without invasive treatments. This is your drug free competitive advantage!
When your skin comes in contact with the Voxx HPT pattern, a sensation is triggered, sending information to your brain.
I started wearing their socks 3 months ago!
The results?
Greater balance and support.
You can learn more and take advantage of their exclusive Neuro Athletics discount.