Wisdom of Age 2: The Physiology of Aging
Hands up who secretly wants to put a pump in the spokes of the Masters racer who keeps putting the hurt to you on the club rides? Aren’t we supposed to get slower as we get older? Let’s examine the research on aging and see what changes are inevitable and what we can address by keeping fit…
While there are inevitable changes in our physiological capacities as we age, how much of it is real and how much of it is due to the way research on aging has traditionally been conducted?
The Problems with Research
In looking at the literature, surprisingly little is actually known or understood about the process of aging in healthy and fit individuals. In large part, this is due to the focus on health research and also the lack of available subjects. You have two basic options when designing a study to compare the effects of aging in humans: 1) Track the same group for many years as they age. Great but obviously logistically difficult, insanely expensive, and not for the impatient. 2) Compare a group of “young” versus a group of “elderly.”
Most of the work in option #2 above have used elderly subjects who were relatively non-fit compared to the “young” group. That’s mainly because it’s difficult to find a large group of highly active elderly subjects who have comparable levels of physical activity as the typical young and highly active subjects used by most research studies. It is also because “sick” individuals have been the target of health research rather than “fit” or “healthy” subjects. Basically, health research funding has largely focused on understanding the nature of diseases rather than the limits of human performance or the role of physical activity in preventing diseases.
Get to the Point!
Why am I prattling on about research design like I’m back in the classroom with my students? The point is that we ultimately know VERY LITTLE about how the natural process of aging impacts physical capacity. Therefore, don’t believe most of the dire predictions you hear or read about the “inevitable” declines with aging! With sustained physical activity and a sound training plan, age really becomes just a state of mind, and physical performance can be maintained at near personal best levels through decades.
So What Gives?
What do we know actually change with age? With the above research gaps in mind, there is or may be a gradual decline in:
• Muscle mass. This will affect your peak force generation and maximal power output. However, by focusing on technique, you can often compensate for this decline by an improved efficiency of movement. Recall that Dr. Alejandro Lucia found that, even in top level pros, riders with a lower VO2max generally compensated with a greater pedaling efficiency. This makes technique drills, from one-legged pedaling through to sprint practices, essential through the years. Also, a focus on high cadence becomes more essential as we age.
• Slightly lower aerobic capacity and lactate threshold, brought about by decreases in hemoglobin concentration and blood volume, along with a slight slowing of other metabolic processes during exercise. This will shift you more towards anaerobic metabolism and lactate production at a given set workload through the years.
• Changes in flexibility is difficult to study. However, I would hazard to say that most of any age-related decrement is more due to an increasing sedentary lifestyle as we age than by any major physical changes. Therefore, the stretching you do through the years can really pay off down the road.
• Overall metabolism may also decrease, though this may again be mostly due to lower activity levels as we age. From my own diaries the math becomes simple. Exercising 200 h/y now vs. 450 12-16 years ago, it’s simply suicide to assume you can eat as much as you once did. Keep an activity AND dietary log for a few days to see where you’re at or else consult a sports nutritionist. Make sure you tailor your intake to your current activity levels!
• You hear a lot anecdotally about a decreased ability to “recover” between hard workouts. This is most likely true and due to a cumulative effect from all the above factors. In most cases, it becomes essential for us to focus even more on the quality of our workouts and to pay even more attention to developing a sound recovery program.
Stephen Cheung is an Associate Professor of Kinesiology at Dalhousie University in Halifax, Nova Scotia, Canada, and is freaked out to be twice as old as his freshman students. His company, Podium Performance, also provides elite sport science and training support to provincial and national-level athletes in a number of sports. He can be reached for comments or coaching inquiries at [email protected].