9 Reasons Your Middle-Aged Body Ain’t Like It Used to Be

“What cannot be altered must be borne, not blamed.” ~ Thomas Fuller, M.D.

Me… racing toward finish line of a local 5K in May 2012, two months after my 55th birthday.

In yesterday’s post, I was a little whiney about how the aging process has affected my running.

Since “knowledge is power”, I decided to research the physiological changes that cause the “slow down”.

The following list came from ACSM’s Certification Review, 3^rd Ed. (pg. 50-51). [Comments in italics are my personal remarks.]

Age-Related Physiologic Changes in Older Adults

1. Maximum heart rate (220 minus age) decreases by 6 to 10 beats per minute each decade.
2. Maximal stroke volume decreases.
3. Decreases in both Maximal Heart Rate (HR) and Stroke Volume (SV) cause significant decline in maximal Cardiac Output (because Cardiac Output = HR x SV).
4. Arterial compliance decreases and arterial stiffness increases (so the heart has to work harder to force the blood through).
5. Blood flow to the muscles decreases.
6. VO2Max typically declines by 5% to 15% per decade after age 25. (However, this rate of decline can be slowed by regular physical activity.)
7. A decline in muscle mass occurs because of progressive decrease in the number and size of muscle fibers. This is particularly true of FAST TWITCH FIBERS (yes, the ones that give runners their SPEED!).
8. Aging brings a 20% increase in the work load of respiratory muscles, but a decrease in the strength of those muscles (No wonder I’m breathing so hard!).
9. Muscle strength declines by roughly 15% per decade in the 5^th, 6^th, and 7^th decades and about 30% each decade after that (I’m 55, so I’m in my 6th decade. I’d better keep lifting those weights at least twice a week!).

The bottom line: I may work as hard as I can to beat the aging process, but it is unavoidable. That’s why I have grown to love age-graded calculators, such as this one at RunnersWorld.com. I also have an app or two on my iPhone that calculate age-equivalent times. When I plug my times into those, I don’t feel so bad after all.

The best news of all is I’m still running after all these years… and THAT is what is most important!

If you’re in your 40s or beyond, when did you begin exercising? Have you noticed a decline yet? Before reading this post, did you know even physically active older adults can’t totally avoid the aging process?