Photo: Ian Dobson
Jenny Higgins Graduated with a 1st class honours BSc in Sport and Exercise Science (University of Limerick). She is currently working towards her PhD in the Department of Physical Education and Sport Science, looking at the interaction of nutrition and exercise on bone health in female athletes. In Jenny’s spare time she is working on a consistent block of training with the goal to be back on track racing soon.
Thank you Jenny for contributing this extremely valuable information on the Female Athlete Triad and bone health for the Belle Lap readers.
Photo: Geraldine Malthouse, Photos in Mind.
Belle Lap: How did you get into running & studying bone health?
JH: I started running when I was about 12 or 13 but only really did schools races for the first few years as I was still swimming quite a bit and playing hockey. It was more of a fun outing than anything but I quickly fell in love with the mud, and hills (I think Irish cross country courses are a bit different to the typical US ones!). I probably didn’t actually start taking running seriously until I was about 16 when I joined a local club. Unfortunately (or maybe fortunately for my research) about 18 months later I ended up sick and injured and haven’t really run well since.
During my time as an undergraduate Sport and Exercise Science student at the University of Limerick, Ireland I was really lucky to be involved in a few research projects and discovered it was something that I actually really liked and could make a difference to someone.
So when I got the opportunity to apply for PhD funding it seemed like a great opportunity to integrate two passions of mine and you’d be surprised how many similarities there are between the demands of research and running.
Belle Lap: What is the Female Athlete Triad?
JH: The female athlete triad is a term used to explain the interaction between energy availability, menstrual function and bone health. It is widely associated with eating disorders or disordered eating however in recent years the definition has been updated to “inadequate energy availability with or without disordered eating” which an important consideration on a physiological level. The presence of one or two components increases likelihood of the third being present. Recently there was a move towards “relative energy deficiency syndrome” (RED-S) which also includes males and other factors affected by low energy availability. There’s currently a bit of debate as to whether the triad should be replaced by RED-S or if there’s room for them both.
Belle Lap: Why are female athletes prone to suffering from the Female Athlete Triad?
JH: There are several psychological and physiological factors that contribute to the female athlete triad.
From a mental health viewpoint there are certain characteristics that increase an athlete’s risk of developing an eating disorder but can also increase the risk of eating disorders not being detected early. These include:
Over-emphasis of the role of weight or body composition on performance
Competition and training clothing which can increase body consciousness
High drive for success or perfectionism
Discipline with training/ diet often encouraged for performance
Stress including pressure to perform and balancing training and competition demands with other lifestyle factors
On a physiological level high intensity & volume training also have a role to play by sometimes suppressing key hormones in the regulation of menstrual function. Exercise is beneficial for bone health but high volume exercise without adequate nutrition can affect bone metabolism and predispose athletes to injury. Intense training requires greater energy intake to support both training and recovery, if these energy demands aren’t met athletes are at increased risk of developing the other two components of the triad.
Belle Lap: Why do some females suffer from insufficient menstrual cycles?
JH: An exact reason hasn’t been pinpointed yet as to why some athletes have irregular or absent menstruation, it’s most likely a multi-factorial problem. Several risk factors have been identified including starting training at a young age, more intense training, psychological stress, inadequate nutrition (both energy intake and inadequate macronutrients (carbohydrate, fat or protein)), low body mass, low body fat, rapid changes in body mass or training. Genetics and training status (particularly overtraining) also influence hormonal health.
The menstrual cycle is regulated by feedback mechanism between various hormones. Strenuous exercise can reduce the activation of these hormonal pathways through the release of exercise and stress related hormones. Fat mass is also a key regulator of endocrine (hormone) action as it contains factors which activate signalling pathways for the female hormones. Low fat mass and negative energy balance are associated with increased levels of certain hormones which negatively impact on menstrual function so this can also explain irregular menstruation.
In a nutshell when the body detects anything that poses a risk it activates mechanisms to protect the body and preserve energy in many cases this includes suppressing hormones to prevent a pregnancy that it cannot support.
Belle Lap: How many cycles does an athlete need per year to be in the ‘healthy’ bracket?
JH: I actually haven’t read anything reporting a set number of cycles a year to be “healthy”. But there is an increased risk with fewer cycles per year. Eumennorrhea or “normal” menstruation is defined as anything between a 24 and 35 day cycle with oligomenorrhea or abnormal menstruation defined as a cycle longer than this. If your cycle is falling outside this range it may be an indication of inadequate hormone levels. That said, if you notice any significant changes in your cycle length (even if within the documented range) it may be a warning sign. In this case it’s advisable to speak to your medical practitioner. This is particularly relevant if a change occurs shortly after a change in training or diet.
It’s important to remember that hormones have many effects on training & recovery not just in bone so even a small change could increase your risk for injury or other health concerns.
Belle Lap: If an athlete is not regularly menstruating, what is the first step to resolve this?
JH: I would always advise an athlete to speak to their medical team and coach if they have any concern. By catching a problem early it can often be resolved relatively easily but if hormone levels are suppressed for a long time it can be much more challenging to restore normal, healthy levels along with having a greater impact on your overall health. Usually increasing energy intake, reducing training volume or intensity or a combination of both is effective in restoring normal menstrual function. The level of change required often depends on the severity of the issue. As we already spoke about strenuous exercise in itself can have a negative effect on menstruation so even though reducing training might be a difficult decision to make it’s important to look at the big picture. The training benefit acquired during the time it takes to resume normal menstruation will be irrelevant if your long term health is compromised or you end up with a stress fracture and can’t race anyway.
Restoring energy balance will often rectify the issue but if you are experiencing prolonged menstrual disturbance it’s definitely important to seek professional help to investigate if there’s any other issues.
Belle Lap: What happens between the stages of disordered eating and the body shutting off menstrual functions?
Again there’s no one simple answer as disordered eating and inadequate energy intake have many physiological effects which in turn influence menstrual function. These include changes in energy availability, body composition and body mass, changes in macronutrient (carbohydrate, fat, protein) intake, psychological and physiological stress which affects the release of hormones.
Each of these factors has a role to play in menstrual function but acting together they have a compounding effect which highlights the risk of disordered eating or low energy availability in an athlete’s health. With regard to the changes that occur between normal menstruation and amenorrhea they can be outlined as follows:
Regular cycles with normal hormone levels
Regular cycles but progesterone production stops early
Regular cycles with low levels of progesterone produced
Regular cycles but egg is not developed
Irregular cycles but still ovulating
Irregular cycles with no ovulation
Absence of menses and ovulation (amenorrhea)
The apparent normal cycles despite low hormone concentration highlights the importance of addressing the problem if menstrual irregularity is detected.
Belle Lap: How is lack of menstrual cycle connected to bone health in athletes?
JH: Over the course of a menstrual cycle several hormonal interactions that also regulate bone occur. Regular menstruation is associated with higher bone mineral density which is an indicator of risk to bone injuries including stress fractures. Oestrogen is a hormone released during the menstrual cycle which also has a key role in maintaining bone health although its exact mechanisms are not fully understood. Healthy bone is continually being removed and formed in the bone remodelling process. Oestrogen has a role in both of these. A lack of oestrogen has a negative effect on normal bone remodelling resulting in lower bone mineral density. This becomes even more apparent in response to exercise when the formation of bone is reduced despite increased damage.
Belle Lap: Which steps can athletes take to help with bone health?
JH: The easiest (and yet possibly not so easy in practice) way to promote bone health is to maintain energy availability through sensible training and adequate nutrition to support this training. Any abrupt changes in training or diet can increase your injury risk but can also impact on your overall physiological and hormonal health so in general I’d recommend make changes gradually and make sure you’re making them for the right reason.
Some simple tips to promote bone (and overall) health:
Make changes in training volume or intensity gradually
Consume a well-balanced diet with a variety of foods
Value your body for what it can do and embrace it’s strengths rather than seeking a body type that just isn’t you – strong consistent training is a far greater indicator of performance than body composition or weight achieved through restriction
Make sure you’re adequately recovering from training and any other life demands – stress from exams or work deadlines can also impact on health so make sure you have some switch off time
Listen to your body (Belle Lap had a great article on what this actually means a little while ago) and rest when needed.
Keep track of your normal menstrual cycle in your training diary – if you have a concern speak to your coach & medical team.
Keeping an eye on hormone levels as part of a regular blood check can sometimes pick up issues before they present in menstruation or lack thereof.
Belle Lap: Can the female contraceptive pill help bone health?
JH: There’s mixed findings on effectiveness of oral contraceptive pills on bone health. As you’ve probably figured out at this stage there’s no one simple answer to what causes poor bone health or menstrual irregularity meaning there’s also no one simple solution. So while the pill might help stimulate bone formation in response to exercise by re-activating that pathway which is oestrogen dependent it cannot address all of the factors that lead to poor bone health as a result of menstrual irregularity and low energy availability.
Belle Lap: Which supplements/ foods can help with increasing bone density?
JH: Normally for specific dietary advice I’d recommend speaking to a dietician but in general consuming adequate energy and macronutrients (carbohydrates, fat, protein) from a variety of sources will help support overall health including menstrual function.
A calcium rich diet also promotes bone health in athletes and non-athletes alike. From the dieticians I’ve worked with they usually recommend consuming dairy products when you can. Obviously if you’re intolerant you’ll have to find other sources but nut and plant based milks usually contain far less calcium.
If you need to avoid certain food groups it’s a good idea to consult with a registered dietician so that you can assess how to meet your requirements from other sources.
Supplements are just that – a supplement not a substitute. It’s best to seek dietary advice before taking them and also be aware of what you’re taking as the food industry isn’t as well regulated as medical industry so the risk of cross contamination with a banned substance can be greater.
Belle Lap: How can bone density be measured?
JH: A dual x-ray absorptiometry scan (DXA) can give a measure of bone mineral density. DXA is often used to measure body composition but was actually designed to evaluate bone density. Body composition measures usually include bone but to get a more accurate picture site specific scans (usually at the hip and spine) are needed. Your results are then analysed compared to a reference population of your age.
Belle Lap: What are the steps to overcoming the triad?
JH: It’s important to remember that the female athlete triad, in particular with an eating disorder is much more than a nutrition issue so a multi-discipline approach is needed. Physiologically improved nutrition and reduced exercise can restore energy availability and menstruation but in order to promote overall health and wellbeing and prevent a recurring problem it’s important to address the key issues behind disordered eating with a suitably qualified professional.
A final note from Jenny:
I’ve spoken about female athletes throughout this article but it’s important to remember that eating disorders are not just a female issue. Numbers reported may be higher in female athletes and while oestrogen doesn’t have such a key role in males, low energy availability still has negative consequences for overall health and performance. The consequences of low energy availability on bone health are quite widely documented but there are also many other physiological implications.