Let's Talk About Sex-- Differences in Physiological Response to Exercise in Men vs. Women
It’s a common fear among women that strength training will cause them to “bulk-up” creating a masculinized effect. The muscle hypertrophy (increase in size or mass) seen in men is due to a hormone, mainly testosterone, which women's bodies only make a very small amount of. Let’s look at some of the physiological differences between men and women and what does, and doesn’t happen with exercise.
Sex-specific differences in body composition don’t begin to occur until puberty in boys and girls. Testosterone (in males) and Estrogen (in females) begin to work their magic on a plethora of our body’s processes. In males, testosterone causes increased bone density and a gain in muscle, or, fat free mass (FFM). Estrogen causes fat-deposition in women, mainly in the thighs and hips. On average, women are 40-50lbs lighter in FFM, and 7-13lb heavier in fat mass than men (lucky us).
For both men and women at about mid 20’s FFM begins to decrease by about .66lb per year, or 6.6lbs per decade. Strength training and cardiovascular exercise become increasingly imperative throughout life in order to maintain or rebuild this loss. It’s a common misconception that strength training is just for men—the truth is it benefits EVERYONE—Ladies this means you too! There are numerous reasons why building FFM is crucial for health.
An increase in FFM= Increase in metabolism
Increased Metabolism= You Burn More Calories Each Day!
If we were to take a piece of muscle from a man and one the same size from a woman, their strength would be equal. This having been said, women have smaller cross-sectional areas of muscle and less mass than men.
When comparing cardiovascular response, men and women are fairly equal in the amount of blood their heart can pump out (cardiac output). Women however, have higher heart rates and a smaller amount of blood pumped out each stroke, due to smaller body size. Women have been found to have resist muscle fatigue more so than men, for reasons that are not quite understood.
Ongoing exercise produces adaptations in females that are different from those of males. Because of hormonal differences, women gain much less FFM with strength training than men. While men experience classic muscle hypertrophy, women only experience slight increases in muscle girth. No Arnold effect. Although contradictory to what you might think, women actually experience the same percentage of strength gains as men with strength training, even though their muscle mass gain is much less. Let me reiterate, women are fully capable of gaining as much strength as men!
Everyone benefits from a strength training and cardiovascular program. It is crucial for our health to increase our FFM and decrease our fat mass. So ladies, we’re not going to turn into Arnold, or even Coach Aaron. Women just don’t have the hormones that produce the increase in muscle mass the way men do. Go ahead and lift those weights, feel empowered, and reap the benefits of strong, healthy muscles!
Sources:
J.H. Wilmore, D.L. Costill, Physiology of Sport, 3rd Ed. 2004.
Forbes, G.B. (1976) The adult decline in lean body mass. Human Biology, 48. 161-173.
Sex-specific differences in body composition don’t begin to occur until puberty in boys and girls. Testosterone (in males) and Estrogen (in females) begin to work their magic on a plethora of our body’s processes. In males, testosterone causes increased bone density and a gain in muscle, or, fat free mass (FFM). Estrogen causes fat-deposition in women, mainly in the thighs and hips. On average, women are 40-50lbs lighter in FFM, and 7-13lb heavier in fat mass than men (lucky us).
For both men and women at about mid 20’s FFM begins to decrease by about .66lb per year, or 6.6lbs per decade. Strength training and cardiovascular exercise become increasingly imperative throughout life in order to maintain or rebuild this loss. It’s a common misconception that strength training is just for men—the truth is it benefits EVERYONE—Ladies this means you too! There are numerous reasons why building FFM is crucial for health.
An increase in FFM= Increase in metabolism
Increased Metabolism= You Burn More Calories Each Day!
If we were to take a piece of muscle from a man and one the same size from a woman, their strength would be equal. This having been said, women have smaller cross-sectional areas of muscle and less mass than men.
When comparing cardiovascular response, men and women are fairly equal in the amount of blood their heart can pump out (cardiac output). Women however, have higher heart rates and a smaller amount of blood pumped out each stroke, due to smaller body size. Women have been found to have resist muscle fatigue more so than men, for reasons that are not quite understood.
Ongoing exercise produces adaptations in females that are different from those of males. Because of hormonal differences, women gain much less FFM with strength training than men. While men experience classic muscle hypertrophy, women only experience slight increases in muscle girth. No Arnold effect. Although contradictory to what you might think, women actually experience the same percentage of strength gains as men with strength training, even though their muscle mass gain is much less. Let me reiterate, women are fully capable of gaining as much strength as men!
Everyone benefits from a strength training and cardiovascular program. It is crucial for our health to increase our FFM and decrease our fat mass. So ladies, we’re not going to turn into Arnold, or even Coach Aaron. Women just don’t have the hormones that produce the increase in muscle mass the way men do. Go ahead and lift those weights, feel empowered, and reap the benefits of strong, healthy muscles!
Sources:
J.H. Wilmore, D.L. Costill, Physiology of Sport, 3rd Ed. 2004.
Forbes, G.B. (1976) The adult decline in lean body mass. Human Biology, 48. 161-173.
Comment
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Comment by Amanda, Nutritionist on September 12, 2008 at 6:22pm - The weaker sex my foot! This is great Emily, thank-you.
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Comment by Suzie Haberland on September 12, 2008 at 3:21pm - There is a difference between bulky and toned. After I started Kinetix, everyone started commenting on how bulky my arms were and I keep reminding them that it's the same old arms with less fat and all toned! Just this morning, a woman behind me at the bank said, "wow, you must be a body builder!" I said no, just a Kinetix junky!
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Comment by Charlie Bailey - K-Mentor on September 11, 2008 at 11:15am - This is really informative. Thanks so much Emily.
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Comment by Coach Heather on September 9, 2008 at 7:20pm - Thanks for the post Emily. GO LIFT LADIES! Grrrrrr.
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Comment by Coach Emily on September 8, 2008 at 12:21pm - You're right. I changed the sentence to be a bit more accurate. Thanks!
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Comment by JR Ozone on September 4, 2008 at 4:01pm - Strictly speaking, women do have testosterone. If they didn't they wouldn't have any sort of sex drive. They do have a lot less of it than men do (unless you're one of the unlucky one's like me, who actually had less testosterone than the average woman before I started getting replacement therapy).
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Comment by Meagan on September 4, 2008 at 12:50pm
- Awesome post Emily!!! I used to love it when Jamie and I were doing the same weight for our last 15.....man he would burn out way faster than me and it would drive him crazy- LOL!!!
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Comment by Coach Lisa on September 3, 2008 at 8:48pm -
I love to feel strong.
My needs are simple:)
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Comment by Coach Danielle on September 3, 2008 at 7:40pm - Good point! We all have something to gain from strength training!
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Comment by Coach Emily on September 3, 2008 at 1:59pm
- Yes thank you for bringing that up!! I decided not to name off all the benefits, there are TONS! That is a great one thought!
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