Bodies are like machines, if you use them a lot they will wear out because of over-use. If you use them very little they will atrophy.
The balance is probably somewhere in the middle, yes, exercise but don't overdo it.
This is a poor analogy. Bodies can heal (i.e. regenerate tissue). Machines cannot. If this analogy was true, ultra-marathoners would be wearing out their joints rapidly. That's not what is being observed though.
What is true is that you can injure joints by increasing the workload too fast. Joints can strengthen and adapt to increased loads but it happens slowly. So don't go from running 5 miles per outing to running 10 miles. Limit yourself to a gradual increase.
http://journals.plos.org/plosone/article?id=10.1371/journal....
http://content.time.com/time/health/article/0,8599,1948208,0...
The issue here is more if the oxidative stress put on your components is offset or even completely overshadowed by the biochemical benefits of exercise, and there is indeed reason to believe that a moderate exercise regime - not unsurprisingly - may yield optimal results.
Exercise too little and your body's machinery will start to suffer from use-it-or-lose-it symptoms. Exercise too much and you will cause an inordinate amount of mechanical wear that cannot be regenerated, plus there may be some biochemical stresses as well.
I know "do it in moderation" makes for a shitty headline that interests nobody, but all things being equal that should probably be the take-away here. I agree with you about gradual increase being advisable, but perpetually aiming for your physical limits may not be the most appropriate course of action for individuals who are already fit.
Underrated point. This is especially noticeable carrying packs. If you don't train to improve your joint strength (tendons and surrounding tissue, not muscle) you will injure yourself. Slowly you can build up to heavier weights. I now regularly train with 10kg, occasionally 15kg and alternate with 1kg. 2000km this year.
The one I have is one of these -- http://www.electrabike.com/bikes/townie/original-3i-3i-eq?g=...
Eh, yes and no. The modern road bike geometry looks the way it does because of the rules in the governing body (the UCI). Up until very recently, they were more interested in keeping tradition, then technological improvements. Think of a bike geometry and design much like an F1 class of race cars.
A faster bike on the road would be a recumbent, and by quite a bit, as recumbents are much more aerodynamic. An added benefit to some is any saddle issues could go away, as there's no saddle, just a seat.
I could also see that the aggressive posture needed to maximize aerodynamics on a regular road bike in an attempt to squeeze out the maximum amount of aerodynamic advantage on a platform that's really not all about that could cause problems in some people, and relaxing this would be more comfortable, without a doubt - exactly like you have observed. You do need an amount of strength and flexibility to stay in those aerodynamic postures.
I've had minor knee issues with riding bikes (and I ride a lot of them!) I was fearing the worse - overuse sounded plausible. Rather, it was simply a muscle imbalance from riding so much, which was pulling me knee in funny ways. PT, stretching, and specific exercises - as well as getting fit for my bike correctly, I've cleared that up, and since have ridden thousands and thousands of miles.
I'm asking these questions because I have been seeing more and more comments along the lines of exercising wears the body out and it breaks, so do not exercise. Exercising with proper form and rest should not do this. In fact the body should be getting stronger. One of the big things I see, particularly with runners and cyclists is very little thought to proper form. Running and cycling appear easy so I think people often do not think about form or technique.
One crucial difference between humans and machines is that humans regenerate and can grow stronger through careful exertion.
With that said, many (most?) top athletes go their entire careers without a joint problem at all.
It does take one 4-5 years to build up to that even from non-sedentary active lifestyles, otherwise maintaining energy for everything else will be impossible.
And my (completely speculatory) hypothesis is that amateur sports (or some pro-sports) or serious goal-oriented strength/physique training will offer benefits down the line, as long as you quit "heavy" exercise after a reasonable amount of time and maintain a moderate amount of exercise for the rest of your life.
After all, Tour de France riders of the past century outlive us by many years, despite most allegedly having been on quite a comprehensive cocktail of anabolic steroids, erythropoietin stimulating drugs, amphetamines, etc..
For those non-repairable components what you want to do is build up the muscle around them. People are so scared about hurting their backs that they avoid doing any exercises to make the muscles that stabilize the lower back stronger. I routinely have people tell me at the gym they do not dead lift because they do not want to hurt their backs. The problem is a) learning to DL will teach you how to lift properly and b) it will strengthen the muscles in your back.
For the record I tore my ACL doing inverts on the wakeboard. Not exactly typical exercising.
1) any individual cell, once X energy passes through them, they senescence
2) from the ovum you grew out of until the last cell alive when you die, only 128 cell divisions happen in that line.
That means there is a finite supply of these repair components, these cells, and so there is a limit to how much energy can go through your body before you die.
Therefore, you probably want to make sure "peak" effort in any reasonable time interval (e.g. a month, maybe a week) is pretty high, to encourage the machinery to remain well-maintained, but average effort is as low as possible.
You should exercise to have a huge amount of effort for maybe 10-15 minutes per month, sprinting for instance, getting your heartrate up to 130+, and keeping it up for a short while, maybe 20-30 minutes, no more. Other than that, you should probably avoid exercise and eat healthy.
There are other reasons gym is not a particularly good kind of exercise. It's just not very realistic. Running or biking in the real world, aside from being more fun than in a gym, is also a lot better for you. And probably, having a weekly game of basketball is far better than that.
Long bouts of endurance exercise can be very taxing and destructive to many body parts.
Exercise as a whole can be done efficiently and effectively without wearing your body out.
Anaerobic exercise (lifting weights) can improve collagen and muscle production via several hormonal pathways. These same pathways tend to have negative feedbacks from excess aerobic exercise (i.e. high cortisol, low GH output in distance athletes).
The data on intense weight-lifting on the other hand is much more conclusive. Heart enargement, aortic dissection and a host of other heart related risks are sharply higher for extreme weightlifters.
Lifting a couple of days a week and doing cardio 3-4 days a week and not going completely nuts with either is probably the safest. But sometimes it's fun to go nuts and shoot for a goal. In the big scheme of things, there are a lot worse hobbies to have.
Again with the extremes; people don't get "big" on accident, and moderate strength training provides a whole host of benefits without the dangers. More people should be lifting, with proper form and modest goals.
How much of that is due to exercise regimes, and how much is due to PEDs? Steroid use is rampant even among semi-serious lifters, and not many people on drugs admit to it.
Interesting. I have a single anecdata point that short-duration heavy lifting cures the degenerative effects of putting miles on one's knees and hips.
The habit stuck, but over time, my knees (right knee in particular) really began to ache and swell badly. Overall energy began declining also, but that's beyond the scope of this context.
At the suggestion of some local "gym bros", I swapped out carbohydrates for fats and switched half of the endurance exercise for resistance exercise. At first it hurt, but over the course of a couple months, my knee issues disappeared completely.
But again, single anecdata point.
BTW, started lifting based on a book suggested on an HN thread years ago: "Starting Strength: Basic Barbell Training" by Mark Rippetoe.
It's a fantastic book for getting into novice strength training, and is fairly entertaining to boot.
10 years ago I got rather bad back problems. I tried karate, running, walking in mountains. It did not help. Then 6 years ago I went vegan for ethical reasons resulting in a drastic diet change. I expected that would affect my health - something for better (like back pain), something for worse. To my surprise that had no effects for health.
Then 3 years ago I read book from www.bodybyscience.net and started strength training. That really helped. Chronic back pain gradually became less bothering. The last time I experienced its acute form when one has to lay for few days was 18 months ago when previously it was 2-3 times per year. The best pert is that I only train once per week for 15-20 minutes.
Also, I like to make it intensive cardio, which (I'm just picking it up again now, so past tense) tended to leave me with the most energy I've ever had in my life.
Over the years, improving my lifting has helped with my posture, hip flexor problems etc.
I guess this may be common knowledge in some exercise circles... but it is probably not common knowledge with the general public.
This article has a summary, though there may be better ones:
http://gettingstronger.org/2013/07/antifragile/
How does the barbell strategy apply to health? A great example is combining occasional, high intensity weight lifting or interval training, alternating with long stretches of rest, recovery and “doing nothing”. The intermittent stress of lifting an extreme weight pushes the body to overcompensate and prepare for an even greater future challenge, but the interlude of rest and recovery is restorative and avoids the downside of chronic overuse. We can extend this idea of a bimodal “barbell” strategy to practices such as intermittent fasting or cold showers. The barbell strategy is the exact opposite of the conventional wisdom to engage in moderate aerobic exercise on the treadmill every day, or to eat regular small meals throughout the day.
This concept is absolutely false. With a proper setup, you should be able to ride all you want without anything "wearing out". Bodies don't "wear out", in fact they respond well when stress is applied correctly. It gets harder as you age, but that's an orthogonal issue. Injury and recovery is part of being active.
I've done 10 Ironmans and seen many, many people in their 40s, 50s, 60s happily cranking out miles and ending up looking younger than when they started. What wears bodies out is not using them.
Or the other option is maybe your hip was doomed if you biked or not... not sure how to totally tease that out with out identical twins studies..
Can you define what you mean by "a lot" in both number of years and typical time spent? Typical routine?
My knees are actually better, though. I've had 3 operations on my left knee and if I don't walk it gets very arthritic. With walking, it's fine.
I've observed having an higher cadence seems to impact less my knees and my back, I've no hard evidence though, it is just modifications I made along the years on my training.
http://www.ncbi.nlm.nih.gov/pubmed/19633305
Atherosclerosis =-=-=-=-=-=-=-= http://www.ncbi.nlm.nih.gov/pubmed/21200345
http://www.healio.com/cardiology/chd-prevention/news/online/...
http://www.ncbi.nlm.nih.gov/pubmed/18426850
Oxidative Stress =-=-=-=-=-=-=-=- http://www.ncbi.nlm.nih.gov/pubmed/16941810