Episode 107 - Female Athlete Series: Part 1: Physiological Differences Between Male and Female Triathletes

Female Athlete Series: Part 1: Physiological Differences Between Male and Female Triathletes

We know that women are physiologically different to men. But how do they differ? And what does that mean when it comes to training for triathlon, coaching females and providing nutrition support?

We’re kicking off Part 1 of a new Female Athlete Series on the podcast with the physiological differences between male and female athletes: Body Fat levels, Muscle mass and strength, Vo2max, Lactate Threshold, Thermoregulation, Fat Oxidation and Hormones.

As you can see, there are lots of differences that we need to take into consideration. 

There is no one size fits all. When we understand female physiology, we can do better and be better. Athletes, coaches and sports dietitians.


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Episode Transcription

Episode 107: Female Athlete Series: Part 1: Physiological Differences Between Male and Female Triathletes

Taryn Richardson  0:00

Welcome to the Triathlon Nutrition Academy podcast. The show designed to serve you up evidence-based sports nutrition advice from the experts. Hi, I'm your host Taryn, Accredited Practicing Dietitian, Advanced Sports Dietitian and founder of Dietitian Approved. Listen as I break down the latest evidence to give you practical, easy-to-digest strategies to train hard, recover faster and perform at your best. You have so much potential, and I want to help you unlock that with the power of nutrition. Let's get into it.

Taryn Richardson  00:36

Today, I'm kicking off with a bit of a series that I want to start all about the female athlete. So today is part one and we're going to talk about the physiological differences between male and female athletes. And what I want to do is drop these episodes over the coming months. I'm not going to do it weekly because all of the male listeners will disengage, although if you have a female in your life, this sort of information is actually really good and useful to know and understand. And what I want to do is get some researchers and some experts in this space to come and join us and share their absolute knowledge bombs around the female athlete because it is a very hot topic at the moment.

Taryn Richardson  01:29

The research in this space is just absolutely exploding. And we saw that begin in around 2020/2019 with COVID. So many more people are aware of the differences of female athletes, and how they differ to males and what we need to do differently to treat them from a coaching perspective, from a nutrition perspective. It is one of the most frequently asked questions that I get is how do we eat or how do we fuel because I'm a female and I'm peri menopausal or a menopausal and my body is changing and things are doing weird things. So how do I actually know what to put in my body to get the most out of it at this stage of life?

Taryn Richardson  02:12

Now I like to teach really systematically and build knowledge without overwhelming you. It is the way that I run the Triathlon Nutrition Academy program each week and each phase systematically builds on the one before it. So what I want to do with this series of the female athlete is to do that, to build strategically and systematically on your knowledge. So thank God we have some cool researchers doing a lot of work in this space at the moment so stay tuned. But historically, there's not been a lot of female representation in the literature and a lot of our evidence based guidelines and what we do is based on men, based on the male. It's been I guess harder to study women, thanks to our beautiful physiological differences compared to our male counterparts. And it's harder to control for things in research for the menstrual cycle phases and to get females at that exact point in time at the exact same part of their menstrual cycle so that we're not confounding the results with changing hormones and things like that.

Taryn Richardson  03:20

But we've seen a huge increase of female participation in sport which is awesome. And we can also see in more recent years, the gap in terms of performance that females are closing in on the men which is also pretty cool. The research shows that females differ from men from a performance perspective of between 10 to 20% depending on the discipline, so swim, bike run, and the race distance. So women differ in men from a sprint perspective but then also a full distance Ironman. And there is a bigger difference in performance the shorter the distance there is. The other thing that depends on our performance difference is the level of the athlete too. So somebody that is more an age grouper type athlete that they are researching versus our very well trained elite athlete into the spectrum as well. There's a cool paper that I'll link in the show notes for you if you do want to dive into the research.

Taryn Richardson  04:23

But if we're talking about elite athletes, so top 10 male and female finishers, the sex differences in Kona World Champs in that Ironman Distance event, we've seen performance decrease over the last few decades. So back in 1990, the difference between male and female performances were about 15%, so females 15% slower than the men. But in 2011, they close that gap further so that their difference was only about 11%. Now if we look back historically at 2018, the race in Kona that year, thanks to a really strong bike performance, Daniella was only 4% slower on the bike compared to the male record holder. So lowering that sex difference in performance in total Ironman performance to 7.1%, which is just crazy. So we are closing the gap on men, which is pretty cool as a female athlete. And I want to talk you through some of the reasons why.

Taryn Richardson  05:27

Now there are a number of physiological differences between male and female triathletes. And so I want to run you through what they are so we can build on this knowledge when we start to talk about nutrition interventions, we start to talk about coaching and training athletes differently from a male and female perspective. Females typically have a higher level of body fat compared to males and that is a physiological thing. We are the ones that become pregnant, carry a baby, and it is an adaptation to protect our internal organs is having more body fat in that area. Elite female athletes generally have 7 to 12% more body fat compared to males. I can link that study for you if you do want to dive into the research.

Taryn Richardson  06:17

And as a result of that, we actually get an advantage in the water because fat is more buoyant in the water. So our time difference or our performance differences in the swim are way less compared to things on the land like cycling and running. Males typically have a larger muscle mass than females. They have the benefit of testosterone, helps to build muscle and we see that particularly in male triathletes. They have much more muscle mass on and have greater muscular strength and lower relative body fat compared to female triathletes. We do know that that whole body composition and morphology has evolved over the last 30 years though. And it's something with a trained eye, you can really visibly see the shift from very lean, very light, kind of almost skinny triathletes, endurance athletes, like think marathon runner build, into much more higher muscle mass, stronger, more robust bodies over the last 30 years as well. So that is going to change that total composition of body fat and muscle mass, male versus female over the last 30 or so years.

Taryn Richardson  07:32

We know also that females typically have a lower VO2 Max and that's irrespective of the exercise modality. Millet and Bentley 2004 found that for elite junior and senior triathletes, the sex difference in VO2 Max was equal to 22%. So 74 versus 61 mils per kilo per minute for males and females respectively. And the ventilatory threshold was similar in senior males and females and corresponded to 74 to 77% of VO2 Max. Now, that sex difference, male versus female in VO2 Max still persists even when we express it per kilograms of fat free mass and there's probably a few reasons for this. Part of it is contributed to the higher body fat levels in females and also our lower red cell mass and hemoglobin for any given body weight.

Taryn Richardson  08:34

Interestingly, lactate threshold appears to be about the same in male versus female. Now, a lactate threshold is the exercise intensity associated with that marked rise in our blood lactate and is usually expressed as a percentage of VO2 Max. So females seem to have the same ability to increase the mitochondria in our muscle. And our mitochondria, if you don't know what that is, it's kind of like the powerhouse of the cell and we can increase those as a result of training in the same way or the same rate as a male, which is pretty cool. Physiologically, females also seem to be better than males at thermo regulation. Typically, females have a smaller body size, so are able to better tolerate hot and humid racing conditions compared to males. So in things like running, a lighter runner is going to produce and store less heat at the same running speed compared to somebody that is larger. So females might be less susceptible than males to overheating during some of those really long races in hot, oppressive conditions.

Taryn Richardson  09:47

Females seem to burn more fat compared to males. Now, we appear to oxidise proportionally way more lipids and less carbohydrate during endurance exercise which is pretty cool. And we need to translate that knowledge into practice. Females have a lower respiratory exchange ratio. And we can kind of hold on to our muscle glycogen and liver stores and utilise those for longer compared to males because we are using more fat as a fuel source, so we're kind of sparing it better than males. So in theory, endurance events that last several hours, we can spare our fuel tank and our fuel tank is going to theoretically outlast the males. But we definitely need more research in this space and this is some of the stuff that's happening right now which is really cool. Because there's differences in our oxidation of substrate, so whether we're burning fat or burning carbohydrates at different phases of the menstrual cycle, too.

Taryn Richardson  10:54

And then how do we then translate that into practice? What do we put in our mouths at certain types of the cycle or if we're racing at certain parts of our cycle, or we're trying to carb load at certain parts of our cycle? What do we do then to maximise everything we can out of our body and perform to the best of our ability? And then finally, obviously, females have different hormones to males. Males are very much more stable, you don't change much. Your testosterone is relatively the same, like we have daily fluctuations but on a monthly basis, you're pretty cool, calm, collected stable dudes some of the time. Whereas females, we have this beautiful flow of our hormones across the cycle. And then, what I love to term that roller coaster shitshow ride at perimenopause, where things just go AWOL, and then changes post menopause as well. Not to mention the impact of things like pregnancy, breastfeeding, postpartum, the use of oral contraceptive pills, IUDs, any form of contraception, and all of those things that go into changing and affecting our female sex hormones.

Taryn Richardson  12:05

And we know that these hormones do affect us. If you're a female, you know exactly what I'm talking about right now. But there's times where we feel like we're training the house down, and other times where we're doing the exact same thing, and it feels like we are flogging a dead horse. Your performance is affected, your recovery can get affected, your sleep can get affected. And I don't know about you, but my food choices change across that monthly cycle as well. And if we have different oxidation rates at different phases, then we really need to dive into this deeper and understand what is going on with our menstrual cycle and how we can then eat to support training based on where we're at. And that's not something we're going to talk about today. I want to set the scene with our physiological differences and we're going to dive deeper into that in another part of this female athlete series.

Taryn Richardson  12:59

So as you can see, there are lots of differences that we need to take into consideration when we are coaching females, when we are trying to nutritionally support females and you know, maybe mentally and emotionally support females as well. There is no one size fits all. And even if we understand what a menstrual cycle does, the textbook menstrual cycle is 28 days, but I don't know many women that have a 28 day perfect textbook menstrual cycle. So like anything with nutrition and our physiology, we need to understand us, n equals one, and manage and adapt this for ourselves. What works for you may not work for your training buddy. But when we understand what's going on, we can do better, and we can be better.

Taryn Richardson  13:29

So I will drop some references in the show notes of this episode if you do want to get a little bit nerdy. Like I said, the research is absolutely exploding in this space at the moment and we are a little bit behind, to be honest. It's actually a little bit embarrassing about how little we know about our female physiology and how to manage that better. But it is coming, be patient. We're gonna get some experts on the podcast to dive deep into what is happening in the labs right now so that our knowledge and understanding is not delayed by 5,10,15 years. 

Taryn Richardson  14:26

Next up in our female athletes series, we're going to dive into some of the nutritional considerations for the female athlete. So keep your eye out for Part 2 coming soon.

Taryn Richardson  14:37

Thanks for joining me for this episode of the Triathlon Nutrition Academy podcast. I would love to hear from you. If you have any questions or want to share with me what you've learned, email me at [email protected]. You can also spread the word by leaving me a review and taking a screenshot of you listening to the show. Don't forget to tag me on social media, @dietitian.approved, so I can give you a shout out, too. If you want to learn more about what we do, head to dietitianapproved.com. And if you want to learn more about the Triathlon Nutrition Academy program, head to dietitianapproved.com/academy. Thanks for joining me and I look forward to helping you smashed in the fourth leg - nutrition! 

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