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The Female Cycle and Training - Part 3


Coach Caron continues her series on the female cycle and how it affects exercise.

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Luteal Phase – Cravings, Bloating and Core Body Temperature

Chocolate, chips, hell anything sweet and starchy will do! Why do women crave more of these foods during the high-hormone, PMS phase of their cycle?

For starters, estrogen reduces our carb-burning ability while it increases our fat burning and the availability of fatty acids.  This is great if you are doing an endurance sport or activity, but for high-intensity training, you will need to eat more carbs.  While you may not need any additional carbs for a typical 60min Madlab class, any workout over 90mins will require additional protein and carbs before your work out and proper fueling for each additional hour (think marathons, triathlons etc.).

The high hormone phase also influences women’s metabolism, increasing caloric burn about 5-10%.  So, during the premenstrual period, women burn about 100-200 additional calories each day.  (Coincidently that is about the number of calories in a small chocolate bar or bag of chips).

The days before a woman’s period begins her clothes may feel a bit tight because high estrogen and progesterone affect the hormones that regulate the fluid in the body.  

Estrogen increases a hormone called vasopressin (aka arginine vasopressin or AVP) which is responsible for water retention and constricting the blood vessels, which in turn increases your blood pressure enough to signal a drop in plasma volume by as much as 8% (so your heart doesn’t have to work as hard). 

Progesterone affects another fluid regulatory hormone called aldosterone which is responsible for retaining sodium.  Progesterone causes less aldosterone which sets off another chain of events that ultimately leads to a reduction in blood volume due to less total body sodium retention. This causes a reduction in cardiac output and blood pressure.

These hormone interplays cause a woman to feel bloated along with the drop in plasma volume. While this may make it difficult to fit into our skinny jeans, it also affects athletic performance. When our plasma volume is low, our blood is thicker, and less blood is pumped out with every heartbeat and all of this can make exercise feel harder. 

While progesterone makes you shed more sodium it also elevates your core body temperature.  Pair this with estrogen lowering blood volume and high hormone days it is harder for women to sweat and therefore cool themselves down. This increases a woman’s risk of heat stress and can cause dangerously low blood sodium levels during endurance events. 

So, to compensate for these effects it is important to keep hydrated and to get enough sodium, especially if you are exercising for extended periods in the heat. There are plenty of hydration products available on the market and consider a high sodium broth like chicken broth or veggie broth the night before an endurance event.