Get Fit: Menstrual Cycle To Your Fat-burning Advantage

First, a primer on menses

The menstrual cycle is measured from day one of your period up to day one of your next menstrual cycle. The length of the average menstrual cycle is 28 days (though cycle length can vary anywhere from 21 to 35 days).

On day one of your cycle — the day when bleeding starts — both estrogen and progesterone are low. During the first part of your cycle (days 1-14), progesterone remains low as estrogen begins to rise, peaking around day 14. Mid-cycle is typically when you would ovulate: the follicle, stimulated by the luteinizing hormone, releases the egg. The follicle becomes the corpus luteum, which produces progesterone. The first part of the menstrual cycle can be thought of as estrogen-dominant.

After ovulation, on days 15-28, estrogen decreases as progesterone rises. You can think of the second part of the menstrual cycle as being progesterone-dominant.

This continual rise and fall of estrogen and progesterone has an effect on fat storage and fat burning. These two hormones also influence two primary fat-regulating hormones — insulin and cortisol. Estrogen decreases insulin’s capacity to store fat, making the body more sensitive to insulin. Both estrogen and progesterone help buffer the negative effects of cortisol, the stress hormone that promotes fat storage.

So what do we make of all this?

How to exercise during the first half of your cycle

Higher estrogen = More fat burning and muscle building

When estrogen is rising during the first 14 days of your cycle, your body will have a higher tolerance for more exercise overall. It’s an ideal time to focus on weight training.

According to Teta, estrogen is an anti-stress hormone; a fairly good anabolic hormone (meaning that estrogen encourages cellular growth and contributes to building muscle); and an insulin-sensitizing hormone, which means that you’ll be less likely to store fat.

Higher estrogen levels also mean that you can consume more carbohydrates and exercise more without negative consequences.  Your body is able to handle more stress, including more exercise overall, and a higher carbohydrate consumption — just don’t go overboard!”

How to exercise during the second half of your cycle

Higher progesterone = More fat storing and muscle sparing

As progesterone rises and estrogen falls the two weeks after ovulation, or during days 15-28, your body will have less tolerance for too much exercise. Aim to pair higher intensity and shorter duration exercises (like heavy weight lifting) with moderate-intensity and longer duration cardio — and lots of leisure walking on most days.

With higher progesterone levels,  you need  to go easier on exercise and lower your carbohydrate intake. During this time, you are less insulin sensitive, which means that consuming carbohydrates (especially refined sugars and starches) — in excess of what you need — will likely be stored as fat.

Exceptions to the rule

Using your menstrual cycle to lose fat won’t work for you if:

• You are naturally more insulin resistant
• You have polycystic ovarian syndrome
• You have hypothyroidism (low thyroid)
• You have adrenal fatigue
• You have irregular periods
• You take birth control pills
• You are on hormone replacement therapy

The hormonal shifts that eventually lead to menopause can begin from age 35 — though many women “feel” these shifts in their 40s. This transitional period is known as perimenopause. You’re still getting your period, but there may be wild fluctuations in your estrogen and progesterone levels that affect your mood, body temperature, mental focus, sleep and appetite.

Perimenopause is very much like experiencing prolonged premenstrual syndrome. Estrogen and progesterone begin dropping, but estrogen levels are higher relative to progesterone. Because progesterone levels are not as high as they should be, a woman will usually be in an estrogen-dominant state. This means that perimenopausal women tend to have increased food cravings. During perimenopause, hormonal changes also affect the thyroid and adrenal glands, which — when combined with lower levels of estrogen — contribute to insulin resistance. This means that perimenopausal women are less able to tolerate carbohydrates and more likely to gain fat.

If you’re in perimenopause — and losing weight is a health goal — it’s important to notoverexercise and to decrease your carbohydrate consumption. Too much exerciseincreases hunger and cravings, especially for starchy carbohydrates. But, your body will be less likely to burn them during perimenopause.