As a younger man, my body was all but indestructible, or so I thought. I could train hard every day, party hard every night and still get up ready to pound the roads or hit the iron early the next day. Every injury was all-but ignored or worked around and rest days were rare. Training sessions were long, intense and frequent. Overtraining wasn’t part of my vocabulary and, despite doing everything “wrong”, my body thrived. I even set my lifetime personal best for 10 miles after no sleep and suffering a hangover!
Sadly, those halcyon days of physical indestructibility were relatively fleeting and by my late twenties and early thirties I discovered that for every hard workout I endured I needed to make sure I put back into my body what my training was taking out. It was necessary to switch my focus from training quantity to training quality. Now, in my mid-forties, I know I have a finite amount of energy and recovery resources available and that I must respect these limits. If I push too hard too often the wheels soon fall of my training wagon. So what happened? Sadly, the effects of aging have finally begun to catch up with me.
Like death, taxes, wet English summers and political scandals, aging is one of life’s inevitabilities. While some of us age more gracefully and slowly than our contemporaries; the result of good genetics combined with a healthy lifestyle, we will all one day experience old Father Time tapping on our shoulders and reminding us that, physically at least, our best days are behind us. Chances are that, like me, your first age-related rude-awakening will come when you have to bend down to pull on your socks and hear an involuntary groan coming from your knees, hips and/or lower back. It’s then you realize that from now on, your training is more about halting decline than scaling new fitness heights.
The Causes of Aging
Aging is an immensely complicated cascade of physiological changes that occur within your body. While life extensionists are quick to point a finger at a small group of specific lifestyle factors such as over eating, exposure to microwaves or excessive use of plastics, all of which allegedly influence the rate at which we age, the truth is that a great many factors are responsible for aging; both physiological and environmental. Some of the changes associated with aging can be minimized by specific exercise or nutritional regimes but they only really slow the inevitable decline we will all experience.
The Physiology of Aging
Your endocrine or hormonal system is essentially the governor of all but a few of the metabolic functions of your body. Hormones tell your cells and therefore tissues, organs and systems how to behave. Hormones are produced by groups of cells called glands and glands tend to shrink as we get older. This means that levels essential hormones such as oestrogen, testosterone and growth hormone decline as we get older. Hormones can be classified as anabolic or catabolic. Anabolic hormones build and repair while catabolic hormones break down and destroy. A reduction in anabolic hormone production means that the stresses of daily life go unchecked and tissue breakdown outweighs tissue building. This is one of the primary reasons that, as we age, it takes longer to recover from injury, illness and heavy exercise.
Many of the physical changes associated with aging can be attributed to hormones – specifically the reduction of anabolic hormone production. Our inevitable physical breakdown is simply a matter of catabolism outpacing anabolism or breakdown outpacing growth, recovery and repair. In essence, our bodies just wear out.
Changes associated with increased catabolism and decreased anabolism include muscle atrophy, reduced functional strength, increased body fat (middle age spread!), decreased bone mass, reduced maximum heart rate, slower digestion, arthritic joints, loss of muscle flexibility and joint mobility. Peak muscle strength and bone mass gradually decline after the age of around 50 although that decline can be minimized with regular resistance training.
In addition, mitochondria, the cells responsible for producing the essential energy-yielding compound ATP, reduce both in size and number. This means that older bodies often tire sooner than younger bodies. This is especially true regarding high intensity exercise. Interestingly, as you age, powerful type two fast-twitch muscle fibres start to morph into slow-twitch type one fibres which means that although strength tends to decline with age, muscular endurance may actually increase. This is one of the reasons that many feats of endurance such as ultra-distance running are dominated by older athletes.
External Factors That Affect the Aging Process
Although aging is the result of the inevitable, natural, slowing down of numerous metabolic processes, there are number of things that can increase the speed at which you age. Needless to say, limiting or eliminating these age accelerators will not keep you young forever. Your individual genes play an important role in the rate at which you age but doing your best to minimize your exposure to these age accelerating factors might just help make your golden years more productive and enjoyable.
Age Accelerators – Free Radicals
Free radicals are unbalanced molecules that contain unpaired electrons in their outer shells. Also known as ROS or Reactive Oxygen Species, free radicals are produced naturally as a result of aerobic metabolic processes and are another reason we age. Ironically, the very fact we need oxygen to survive is also the reason we age. Five percent of all consumed oxygen “goes bad” and results in ROS formation. The very stuff we need for life also results in our demise! Holding your breath will not reduce ROS formation but keeping stress levels as low as possible, not smoking, limiting your exposure to toxins, moderating sun exposure and avoiding pollutants will.
ROS are responsible for many of the changes associated with aging. ROS production is linked to stress, smoking, pollution, sun bathing and a poor diet. I bet you know at least a few people who look “older than their years” and now you know why!
The following are attributable to the effects of ROS
- Decreased skin elasticity leading to increased and deeper wrinkles
- Macular degeneration leading to age-related reduced vision
- Degeneration of synovial fluid producing membranes leading to drier, less mobile joints
- Reduced blood vessel elasticity leading to increased blood pressure and lowered maximal aerobic fitness
- Reduced muscle, tendon and ligament elasticity leading to reduced range of movement
Exercise and Free Radicals
Ironically, exercise increases ROS production. Increased mitochondrial activity and muscle ischemic reperfusion injury both increase free radical production. Mitochondrial activity describes the taking in of fuel and the production of ATP. When you exercise, mitochondria must work much harder than usual to provide your muscles with the necessary energy to power you through your workouts. Like a furnace burning coal, the more fuel you process, the more waste products are produced. In the case of increased mitochondrial activity, the more energy you need for movement, the greater the production of ROS. Mitochondrial activity is highest in cardiovascular and endurance training.
Before you heavy weight trainers start to congratulate yourselves on hitting the weights instead of pounding the pavements thinking that you have escaped the threat posed by ROS – think again! When you contract your muscles to lift heavy weights, blood flow is essentially shut off for a split second and this creates a significant build up in blood pressure. The blocking off of blood flow is called ischemia. As your muscles relax, blood flows rapidly back into your muscles. This is termed reperfusion. Ischemic reperfusion injury is the cellular trauma caused the on again/off again flow of blood through your muscles. The result? ROS.
Before you decide to live a life of sloth in an attempt to put of your inevitable demise, it’s important to note that exercise also results in an increased production of anti oxidative enzymes which neutralize ROS. These enzymes counteract many of the harmful effects of ROS and include Super Oxide Dismutase (SOD), Catalase, Methione Reductase and Glutathione Peroxidase (GPX). Anti oxidative enzyme production increases with exercise performance so you can forget using not exercising as an excuse for life extension! In fact, exercise provides the most effective antidote to aging and can help stave off many of the degenerations associated with the advancing years. The old joke of “you only have so many heart beats to spend in a life so don’t waste them exercising” is exactly that – a joke.
Longevity versus Quality of Life
It wasn’t that long ago, at least in evolutionary terms that, if you become weak, ill, injured or otherwise unable to fend for yourself, you would be left in your cosy cave to expire at your leisure. If you were unable to physically contribute to the hunting and scavenging essential for primitive survival then, unfortunately, it was time to cash in your metaphorical chips. Chances are that, right up to a short time before your ultimate demise, you were fit and strong and healthy. As soon as you were unable to catch food to eat or fight off predators, your days were numbered. Chronic diseases didn’t really exist in those days and many of the conditions that now plague modern man such as obesity, diabetes and arthritis were not the global epidemics that they are today. In fact, many of the diseases that plague modern man are a direct result of our longer lives. For example, Stone Age man didn’t suffer from degenerative diseases like CHD and osteoarthritis simply because his body never got the chance to accumulate the necessary stress required to bring on these sorts of chronic conditions. Pre-industrialised life may have been brutally hard, dangerous and comparatively short but, one can argue, quality of life was much higher. Our ancestor’s lives burned bright and short whereas the life of modern man tends to burn longer but much less brightly. Modern medicine and surgical procedures are now able to prolong life significantly but is a long life necessarily that desirable especially if life quality is low?
In part two of this series on aging, we will examine strategies, both nutritional and physical, that may result in not a longer life but certainly one that is more productive.
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Excellent piece of writing and really looking forward to part 2!
Thanks for the kind feedback Malcolm – more articles on aging later in the week!
I feel so terribly tired and weary today. Why? Am I eating the wrong food, am i just too old.!!
You’re never too old Rita but as we get older, it’s important to listen to your body and rest when it tells you. Keep moving to maintain mobility but pick your exercise battles wisely as recovery does become slower as the years advance.