No ladies - I am not talking about going for a bike ride with your BFF. I’m talking about your other ‘friend’ - you know the one that visits you once a month. You know….
Aunt Flo is visiting
Clean Up at Aisle One.
Come on - it could be worse. I could be making puns about PERIODization Training..
But from a training and racing perspective does it make any difference ?
Here’s why it does.
Your typical cycle is 28 days long and so your first day of menses would be considered day 1. You typically complete that by about day 5-7 and then the mucosal lining of your uterus begins to rebuild and proliferate in preparation for the potential of an egg implantation. From day 1 all the way up to ovulation, which is usually about day 14-15, is called your follicular phase and then you move in to what’s called the luteal phase
You’ve got your follicular phase; you’ve got your luteal phase. During these phases you have different levels of hormones based off the need or the lack thereof to repair the endometrial lining in the uterus. As a lot of women know, there are different symptoms that can accompany this cycles and some women don’t get any of those symptoms, some women get lots of these, some women get some pretty significant discomfort. From a training and racing perspective however it’s just not changes in your mood or the way that you feel. There are also some pretty significant changes in exercise performance and also the way that you respond to fats and proteins and carbohydrates based off of where you’re at in your menstrual cycle.
In simple terms we’ve got our low hormone phase, which occurs early in the cycle, and a high hormone phase, which occurs later on. In the High hormone phase women produce a lot of estrogen and estrogen will decrease how much you rely on your liver’s storage carbohydrate, your muscle storage carbohydrate and increase your use of fat. This means that when you’re producing a lot of estrogen, you have a bigger capacity for burning fat and for sparing muscle and liver carbohydrate or what’s called your storage glycogen. When you want to go up to a very high intensity during exercise such as for HIIT sets, swim sprints, TABATA etc., when you’re in that high hormone phase you might need a little bit more carbohydrate. During the low hormone phase, when you are producing less estrogen, you can ingest less carbohydrate because you’re going to tap into your liver and into your muscle carbohydrate a little bit more efficiently.
During the high hormone phase (day 14 - 28) you may need more carbohydrate in order to support HARD interval sets.
It is also why you might feel flatter doing exactly the same set later in the cycle (high hormone) than earlier (low hormone) as you are less efficient at tapping into the 'fast' energy source - glycogen.
The other really interesting thing that happens is that during that high estrogen phase you’re using more fatty acids. This means you return to your pre-exercise metabolic rate much more quickly with the impact on training being that your post exercise feeding window when insulin sensitive is high is much shorter. You should prioritise your post workout meal to get it in right after you finish your workout when you’re in that latter phase of your cycle if you want to optimize restoration of things like your storage glycogen or restoration of amino acids. Whereas men might be able to wait a good 2 or 3 hours because their metabolic rate is still elevated and they’re still able to restore a lot of those metabolites, Women, especially during their latter phase when in their high hormone phase, have a much smaller window and should aim to refuel as soon as possible after the session.
Whilst I’ve spoken about Estrogen and its impact on glycogen usage there are actually other hormones that cycle through the time frame. During the high hormone phase you not only have high amounts of estrogen but you have a high amount of progesterone as well. Progesterone increases how much protein is used during exercise which means if you’re going to use amino acids you'll most sensitive to them during the High Hormone phase.
What does this mean?
During days 1-14 (Low Hormone Phase) you might do better with higher intensity or harder workouts as you are better able to tap into storage glycogen, less reliant upon amino acids and less efficient at burning fat as a fuel. Once you shift into days 14-28 you might do better during longer workouts where you’re actually got more estrogen to be able to tap into fat more efficiently, you’ve got more progesterone and you’re able to utilize amino acids more efficiently and that might be a better time to do your longer slower workouts.
Hydration is also important here. When you have elevated level of progesterone you’re baseline body temperature is increased significantly and when your baseline body temperature goes up not only you’re going to sweat more but you’re also going to need more fluid typically to maintain body temperature. Now when you get high estrogen AND high progesterone you get a reduction in your plasma volume and that’s why you get a lot of swelling a lot of times during the latter phases of your cycle. A lot of the volume from blood plasma goes between cells instead and causes bloating that you typically experience. Because of this blood volume drop, you might need a little bit more water and a little bit more electrolytes when you are in that phase of elevated progesterone and elevated oestrogen (High Hormone phase)
Due to this reduction in blood volume during the High Hormone phase you might find that you tolerate hot exercise a little bit less and when you go for a run or a ride you need a little bit of extra fuel, you might do better with a little bit more electrolyte intake like salting a little bit more of your food during that part of your cycle.
Finally, when you’re producing more progesterone and more estrogen, you are also going to get increased production of specific hormone called relaxin and relaxin is something that pregnant women are gonna produce in high amounts but also that you’re gonna produce towards the latter phase of your cycle in higher amounts and this is responsible for softening and relaxation of ligaments especially the pubic symphysis (hips). When you have a high amount of relaxin circulating in your bloodstream, it can do things like weaken your spine a little bit so you’re unable to withstand impact and twisting forces quite as much. You might get increase propensity for knee injuries or hip injuries or ankle injuries so once again during the high hormone phase you MAY want to drop the weight slightly or, more importantly, be super careful with technique knowing that your body is a bit ‘looser’ and less able to protect itself.
Days 1-14. Better suited to high intensity exercises, weights
Days 14-28. Better suited to longer sessions but be conscious of lower blood volume (heat sensitivity) and shorter refueling window.