Strength Training's Effects on Longevity



Aging’s Effects on Our Musculoskeletal System
When we are born, our muscular and skeletal systems undergo growth at an incredible rate during infancy, followed by a second growth spurt at puberty which lasts through most of our adolescence. This growth occurs naturally in the absence of any limiting factors. Once we reach adulthood, this natural growth rate reaches its peak and within a few years begins its long, steady decline.

After reaching peak strength at around 25 years of age, our muscular system plateaus and then declines at a rate of about 3 to 5 percent per decade after the age of 30. This is known as Sarcopenia. This same time frame can be applied to bone density as well where, after it peaks, bone strength naturally weakens (a process known as osteopenia), and for many, leads to osteoporosis (a disease characterized by low bone mass and structural breakdown).

This decline and eventual failure of our musculoskeletal system will have a more profound effect on how we live in our later years than it will on the actual number of those years. As our physical abilities degrade, we could compensate for its effects by reducing the amount and intensity of our activities, thereby greatly reducing the direct risk of injury or death. This seems to be the approach that most people opt for.

While this may seem like a logical approach to aging, the years we gain in the short run will be taken from us in the long run. As we get weaker, we will get slower, our balance will diminish, and we will start using the tools and devices available that will allow us to still get around. This process will become a downward spiral that will lead to our ever-decreasing mobility and eventually frailty.

It is not just that we are slowing down, it is our entire body’s systems that are slowing down. Arguably, we are not only allowing this to happen, we are making it happen. And by doing so, we are actually telling our body’s systems that we have reached the end of our physical usefulness and are ready to expire. Whether this is a built-in obsolescence, or just a random occurrence, it is what happens nonetheless.

This process is not inevitable, well not entirely. Eventually, no matter how hard we try, our body’s systems will weaken, break down, and finally quit on us. But the idea is to push that process further (much further) back in our aging timeline. We want to dictate the terms of our physical demise, not the other way around. Our goal is to cross the finish line beaten and battered, tattered and torn, and grateful for every bit of it.

So, how do we do it?


Strength Training is a Start
It could be said that our musculoskeletal system doesn’t weaken from aging, it weakens from disuse. Not just sedentary-type disuse, but the lack of intensity that it was built for. We need to subject our muscles and bones to the type of stress induced repair and recovery that can only occur after a sufficient training session.

There are four conditions necessary for proper strength training:
  • Intensity - the resistance should be enough that the working muscle reaches fatigue after 8 to 12 reps (any more and the intensity is insufficient, any more and you risk injury)
  • Duration - 2 to 3 sets of a given exercise should be sufficient to reach fatigue for each muscle group being worked.
  • Volume - A given muscle group should be worked at least every 4 to 7 days. (a bigger rest between workouts and the muscle fibers begin to relapse back to their previous state, a shorter rest period may not allow the muscle group to fully recover).
  • Type - The best overall benefits will come from a training regimen that focuses on the bigger muscle groups (legs, back, chest, and core). This will generate the largest production of the hormones needed for repair and overall growth.
    • Functional strength training is useful and may be even necessary for improvement in a given sport or activity. Integrating functional strength workouts into an overall program is highly advisable.
Benefits Beyond Strength
The body’s response to a strength training session of sufficient intensity, duration, volume, and type is to produce a myriad of hormones required for the post-workout recovery, repair, and growth phase. These hormones include testosterone, human growth hormone, and cortisol.

Note - acute, short-term elevation of cortisol levels will bring about the production of ( ) which will neutralize its harmful effects, whereas the chronic production of cortisol via long-term, continuous stress will not trigger the same beneficial counter measures.

These same hormones along with Insulin and Insulin-like Growth Factor 1 are crucial for bone growth as well and are reported to increase after strength training sessions.

Additionally, exercise of sufficient intensity has been shown to increase levels of dopamine, norepinephrine, and serotonin (the feel good hormones), which are not only necessary for mental health, but they also compete for receptor site positioning at the cellular level with cortisol (study from BrainPlacticity). So inducing production of these hormones would logically assist with bringing our cortisol level back down to resting levels after exercise.

Read more - Testosterone, Cortisol, and Chronic Inflammation (coming soon)

Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals (from PubMed).


What About Diet?
Strength training alone will not get our musculoskeletal system where we need it to be. We also need to give it the proper nutrition necessary for growth. While this will be the subject of another post (coming soon), just be aware that our bones need the right minerals (calcium, vitamin D, and phosphorus), and our muscles need protein. Neglecting the dietary need for them would make our strength training workouts nearly futile.

Conclusion

It is no secret. We know we need to exercise. But more than just exercise, we need the right type of exercise. Walking, while a great first step in getting on the right track, is not enough. Even running or, better yet, trail running, is great and necessary, but it is not enough. We must build strength as well if we want to maintain our ability to get out and challenge ourselves. An adventurous life not only requires it, it demands it. And our longevity will reap the ultimate consequences of this lifestyle choice!

Oh, one more thing - we are never too old to start.