3 The period is a vital sign of health
The changes in hormones that result from RED-S impact on many systems of the body with bone and reproductive health being particularly at risk. In Activity 2 Dr Emma Ross from The Well HQ [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] explains how and why low energy availability will impact on the menstrual cycle, and the reproductive and skeletal systems.
Activity 2 Loss of periods – a red flag to female athletes
Timing: Allow about 15 minutes
Watch the video where Dr Emma Ross explains the ‘brain to ovary’ link and how it is affected by low energy availability. Then answer the following questions:
- Why does the brain choose to switch off the menstrual cycle when there is low energy availability?
- Why is the maintenance of bone health so vital to young female athletes?
Download this video clip.Video player: boc_sfps_1_session7_activity2.mp4
Transcript
EMMA ROSS
The hormones of the menstrual cycle, even though they are released by the ovary, are actually regulated by the brain. And it’s this brain to ovary signal that can be interrupted when we have low energy availability in the body.
Now, what that means is that we’re not getting the right amount of fuel to meet the demands of our training and our life, and that creates low energy availability. And what that means in a woman’s body is the brain has to decide what do I not need to be working for life to still be able to go on? And the only system that a woman can lose without it risking her ability to sustain her life is her reproductive system.
So the brain switches off our reproductive system because we can’t sustain a pregnancy when we don’t have enough energy available to us. And what that does is not just limit our ability to become pregnant, but it also suppresses those really important hormones that are associated with the menstrual cycle.
When the menstrual cycle is suppressed, it means that periods will stop. And actually this is a real red flag for female athletes because when periods stop, it’s probably a sign that they’re not getting the balance of training, recovery, and fuelling right.
We know that the hormones of the menstrual cycle are absolutely vital, not just for reproduction, but for lots of other systems within our body, like our immune function, our cardiovascular function, our brain function. And so it’s no surprise that when the menstrual cycle hormones are suppressed during periods of low energy availability, that interrupts the function of all of those systems.
One particularly important effect of suppression of the menstrual cycle is the lack of oestrogen and its impact on bone health. And so oestrogen plays a really important role in building bone density and bone strength. And so when we don’t have oestrogen, we can’t build bone strength.
And one of the telltale signs that an athlete is suffering from low energy availability is often bone fractures, because the bone strength has been lost because oestrogen hasn’t been there to help it develop. It’s not just the short-term effects of low energy availability that are important. There are also really significant impacts on the long-term health of an athlete.
For example, when we think about bone health, a woman actually lays down all of her bone density and her bone strength before she’s 30. And from that age onwards, we’re either maintaining or declining in terms of bone strength.
And so we really need to make that peak bone strength as high as possible. And if we haven’t got oestrogen helping us do that in our teens and 20s, that can have significant impact on bone health across our life.
The coach can play a really important role here. So ensuring that athletes arrive to training well fueled, ensuring that they are eating the right things after they've been training or performing, because those things are really important for maintaining good energy availability and avoiding the consequences of energy deficiency.
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Discussion
- While oestrogen is produced by the ovaries, its production and release are controlled by the brain through the brain to ovary axis. The brain switches off the menstrual cycle to conserve energy for other processes that are vital for life. The reproductive system is the only system a woman can lose without risking their life, and a pregnancy will increase the energy demands of the body. As a result the menstrual cycle is disrupted to prevent a pregnancy that could not be sustained, and the period stops. However, this impacts oestrogen levels, and this is a vital hormone in its role in building and maintaining bone strength.
- Maintaining long-term bone health is really important for young female athletes, as the teenage years and twenties are times when the female is building bone to achieve peak bone strength, which occurs by around age 30. From this point on bone density will slowly decline across the lifespan. For women in particular, whose bone health can be impacted significantly by the loss of oestrogen after the menopause, building bone strength in the teens and twenties is vital to achieving a high peak bone density, to offset bone loss throughout later life, and to reduce the risk of osteoporosis and bone fractures.
RED-S will affect other body systems as well as the reproductive and skeletal systems. The following figures show the impact of RED-S on other body systems (from Mountjoy et al., 2018).
Cardiovascular system (heart and blood vessels)
Impact of RED-S:
- Irregular heart beat
- Lower heart rate
- Lower blood pressure
- Low red blood cell count (anaemia)
Digestive system
Impact of RED-S:
- Slower digestive speed
- Increased time food spends in intestines
- Constipation
Immune system
Impact of RED-S:
- Increased likelihood of illness
- Increased colds and flu
- Increased body aches
- More headaches
Endocrine system, including the thyroid gland
Impact of RED-S:
- Reduction in rate at which calories are burned
- Increase in the hunger response
As you will see in the next section some of these have a profound impact on physical performance.