Many folks (me included some years), trying to stay healthy and active by running 10Ks and marathons, developed a high maximum oxygen uptake and low pulse rate. However, exercise science has discovered that we were exercising only half our muscles. Likely to our detriment.
Our bodies have three types of muscle fibers: slow, fast, and faster. These descriptions have nothing to do with how fast they contract, but the amount of time it takes for them to fatigue. Slow twitch are mobilized during aerobic exercise -- jogging, rowing, cycling -- and rely on oxygen. The fast twitch are mobilized in the transition from aerobic to anaerobic -- sprinting and intense weight lifting -- and rely on both oxygen from your blood and glycogen, stored in your muscles. The fastest fibers, which are mobilized for only a few seconds of the most intense exertions and called white muscle fibers, rely solely on glycogen.
Unfortunately, if you only do aerobic activities, your fast twitch fibers sit idle and unused. You might wonder so what? Because you are compromising your long term health and well-being. They play a vital role in your health by helping your body naturally produce human growth hormone (HGH), which is especially important to a TOJ.
Once we pass our twenties, our bodies start to produce about 14% less human growth hormone per decade, a process that is called somatopause. This leads to a host of potential long term health problems. The most visible one is the tendency to carry more fat in your belly and hips. But the less visible ones are more serious, including loss of muscle mass, cognitive decline, decreased bone density, decreased totally body water, and insulin resistance, to name a few.
Watch this informative discussion between Dr. Joseph Mercola, a burnt-out runner, and Dr. Phil Campbell, trainer and author of Ready, Set, Go! Synergy Fitness. Campbell provides an insightful explanation on the role of intense exercise and natural production of human growth hormone. The good news is that very intense anaerobic exercise give you the same natural HGH boost as an injection.
Campbell has a training system that relies on extreme exertion. He often uses sprinting because he professionally coaches athletes who want to run faster, but his technique can also be applied to exercise bikes and other training apparatus. It is very simple: you go all out for 30 seconds, rest for 90 seconds, then go all out again for 30 seconds. Until you have done 8 reps. He says if you can do more, you aren't going all out. Mercola says in the last few seconds of these reps he was "nauseous" and "almost unconscious."
What Campbell advocates is at the root of all types of anaerobic training and has a sound physiological basis. It might sound extreme, but it's really not. You might feel very uncomfortable, but it's only for a short time, and there's a big payoff. You cannot stop the body changes that come with aging, but you can slow them.
So an aerobic/anaerobic balance is good for you. Yesterday, I enjoyed a leisurely trail run. The weather was clear and beautiful. I always run a few days a week. It releases endorphins giving me the runner's high, and my slow twitch muscles love it.
Today, it's snowing. Perfect for a fast twitch day.