As you age changes take place in your cardiopulmonary, musculoskeletal and nervous systems. These affect you as an athlete and your activities of daily living. Fortunately through exercise you can slow down many of these changes and in some cases reverse them!
The cardiopulmonary system is composed of the heart, lungs, arteries and veins. Every activity from taking a nap to exercising vigorously requires a well-functioning cardiopulmonary system. As you age:
Your cardiac output decreases by about 30% between the ages of 20 and 80. Cardiac output is a function of heart rate and stroke volume, how much blood your heart pumps per beat. While your maximum HR inevitably declines, through exercise you can maintain your ability to sustain a reasonably high HR and slow the decrease in the elasticity of your heart, which is what reduces stroke volume. In fact, with moderate-intensity exercise you can improve your maximal oxygen uptake by 20-30% over a sedentary lifestyle, which is comparable to the increases observed in younger subjects. Exercise capacity, the ability of the heart to support a high level of exertion, has been shown to be a stronger predictor of mortality than hypertension, smoking and diabetes!
When exercising, getting enough oxygen depends more on breathing more frequently rather than the depth of breathing, due to the decreased elasticity of the lungs, increased stiffness of the chest walls and weakening of the respiratory muscles. However, with training, improvements in ventilation take place and pulmonary function doesn’t seem to be a limiting factor for physical activity.
Flow of blood to the limbs is reduced at rest in older individuals; however, fortunately the ability to deliver sufficient oxygenated blood during exercise is not affected, provided that you keep exercising.
Bottom line: If you exercise regularly and consistently, then you can significantly slow the aging process in the cardiovascular system, which will continue to deliver enough oxygenated blood to the muscles to support more exercise, whether you are cycling for health, overall fitness or for performance!
The musculoskeletal system includes all of the skeletal muscles that move our bodies in different ways. As you age:
Your muscles atrophy. The cross-sectional area of your muscle fibers decreases, resulting in a loss of strength. You have two types of fibers: slow-twitch (ST), which fire slowly and have great endurance, and fast-twitch (FT), which fire explosively when you need power. You differentially lose muscle mass in the FT fibers because as you age you tend not to do activities that require a lot of power. Even though you have a greater proportion of ST muscles due to differential atrophy, your endurance is not enhanced. (ST and FT refer to how rapidly the fibers contract, not your cadence.)
Unfortunately, as your muscles atrophy from less use, they are replaced by fat and connective tissue.
However, the rate of atrophy can be slowed with exercise, and most of it can even be reversed with resistance training! Note that only the muscles that you train regularly retain or regain muscle size. Progressive resistance training has the same effects on the muscles of nonagenarians as it does on 25-year-olds!
In your body different metabolic pathways produce energy, and the particular pathway(s) used at any given time depend on the fuel source and the intensity of activity. These pathways use enzymes to produce energy, and with aging the production of the different enzymes decreases; however, with exercise the enzymes available increases!
Bottom line: Through regular resistance exercise you keep your muscles from atrophying and keep your metabolic pathways functioning at a sufficient level. Thus, muscle strength doesn’t have to be a limiter to your exercise for health or for performance.
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The book describes the physiological changes that take place as you age, how to assess your current fitness and the training principles that apply to older roadies.
Coach Hughes incorporates the latest research and most of it is new material not published in his previous eArticles on cycling past 50, 60 and beyond.
Anti-Aging: 12 Ways You Can Slow the Aging Process gives you the tools you need to slow the inevitable decline in your health and fitness.
Anti-Aging describes the physiological changes that take place as you age, how to assess your current fitness and the training principles that apply to older roadies.
The nervous system includes the Central Nervous System (CNS) and the Peripheral Nervous System (PNS)
The CNS is made up of your brain and the brain stem, the vital link between your brain and the spinal cord. Your brain receives sensory inputs from all parts of your body and makes decisions, conscious and unconscious, about how to respond. Your brain starts to shrink in your 30s, and its weight can decrease by about 10% by the time you are 90. Fortunately, physical activity may slow the progress of tissue loss in the brain.
The PNS includes the nerve receptors throughout the body that send messages to the brain, the motor units that fire in your muscles, telling them to contract, and the nerve pathways between all of this and the brain. As you age it takes longer for signals to travel both directions on the nerve pathways. This doesn’t appear to affect functionality. However, you have a striking decline in the number of motor units beginning in your 70s.
Power and pedaling economy on the bike are the result of not only aerobic capacity and leg strength, but also neuromuscular facilitation, the ability of the body to coordinate precisely via the motor units the contraction of individual muscle fibers. Even if you do resistance training to prevent atrophy, later in life you slowly lose power as a result of the loss of motor units.
Your reaction time slows, too, as a result the loss of motor units and slower conductance of nerve signals, and may be exacerbated by the atrophy of FT fibers. You can’t sprint as fast and, more importantly, this slower reaction time has consequences for activities of daily living. Suppose your foot encounters something unexpected. It takes slightly longer for the message to get to your brain, your brain to process the data and for the instructions to get back to your leg and foot. As a result, you may fall.
Your posture may get worse as you age, in part because of increasing stiffness but also because of the decline of the nervous system that controls your posture.
Physical activity may also retard the degradation of the conductance of nerve signals as well as a recovery from injury.
Bottom line: If you continue to exercise, you can slow the aging of your nervous system, which will be adequate to support your exercise program and activities of daily living for decades to come!
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Dan Boice says
Thanks for the hopeful and helpful reminders, Coach!
Could you also speak to how to better retain bone density? A few years back, I was diagnosed with osteopenia. Since then, I’ve been taking calcium supplements and have started running, but haven’t rechecked the density. Seems like a concern that many cyclists might share.
Richie Fletcher says
This is true for me as well. I believe that one must also do progressive resistance training. Running is good impact training for musculoskeletal and weight training for the entire system is an added benefit. As we know, taking calcium, magnesium, vitamin D, etc. alone will not prevent bone loss.
Edward Custer says
As a 75 year old cyclist most of what you say is true. My major problem as I age is mental. I am gradually becoming slower, and during the winter I have to dig deep down to get on my bike. I don’t keep track of my average speed anymore. I have some real bad days, but sometimes I have a real good ride. I’ve had my share of bad crashes, illnesses, surgeries. Being older is a little bit different as you ride because you love doing it. I don’t push myself to my limit anymore, as I will blow up. Riding is more-less a life style. I hope to ride into my 80’s. Don’t quit. When you get passed by another rider, smile and say have a great ride! No one can stop the aging process, but don’t go down without a fight.
Bill Wegesser says
Good article. I’m 65 and where I used to be able to ride forever with a pulse of 154 ~10 years ago, I find now I really have to push myself to get up to 140. Remember to keep biking though! If you stop biking, you’ll fall over!
Steven Koester says
Most of the research shows that calcium supplementation is not helpful for prevention or treatment of bone loss. Men or women. Strength training and weight bearing exercise seem to help, and maybe food selection [look up acid-alkaline diets as it pertains to osteoporosis.] Good luck.
Gerry Mitchelmore says
JAMA (doi:10.1001/jama.2017.19344) – Calcium, Vitamin D Supplements Not Associated With Lower Risk of Fractures RESULTS: “Supplements were not associated with less risk for new fractures, regardless of the dose, the sex of the patient, their fracture history, calcium intake in their diet or baseline vitamin D blood concentrations.” STUDY CONCLUSIONS: “These findings do not support routine use of supplements containing calcium, vitamin D, or both by older community-dwelling adults for prevention of fracture.” BOTTOM LINE: Supplements containing calcium, vitamin D or both did not appear to protect against hip fracture and other bone breaks in older adults.
Dan Boice says
Thanks, Gerry. And I know that supplements are always a dicey proposition. Good to get JAMA’s take on it.