Humans are designed to improve

When we regularly perform endurance exercise, many positive changes occur inside us. I believe that this is due to the way our ancient ancestors adapted our bodies to walk and run for long distances. Assuming then that our physical design and purpose is long distance forward motion, it’s no surprise that we feel so good when we do it—we are going back to our roots.

Is our body lazy?

Maybe this is too strong a statement. Let’s say that our bodies want to conserve resources by doing the smallest amount of work they can get away with. If we are sedentary and never exercise, the heart slowly loses it’s efficiency, deposits build up in the arteries, the lungs become less efficient because they don’t have to be efficient. Only when we put these important health components to a gentle test, as in long runs, is the body forced to respond by improving in dozens of ways.

Teamwork

When called into action, the heart, lungs, muscles, tendons, central nervous system, brain, and blood system are programmed to work as a team. The right brain intuitively solves problems, manages resources, and steers us toward the many lasting health benefits resulting from running and walking.

Your leg muscles significantly help to pump blood back to the heart. By gradually extending the length of your long run, you produce very fit muscle cells. They get stronger and more efficient in moving blood in, and pushing waste produces through the system and back to the heart. Some cardiovascular experts who study the heart believe that the cumulative effect of endurance-trained leg muscles can pump significant blood flow back to the heart.

Why does long distance exercise keep the heart healthy?

Your heart is a muscle, and responds positively to endurance exercise. The slight increase in heart rate, maintained during a gradually increasing long run each week, keeps this most important muscle in shape. A strong and effective heart pumps blood more effectively not only when you exercise. Heart specialists say that this “fit” heart is more resistant to heart disease at all times.

But, if your diet is full of artery clogging foods, a strong heart will not make you immune to heart disease. A diet that is high in saturated fat and trans fat has been shown to significantly increase the chance of heart attacks, strokes, etc.

The lungs

On our long runs, the muscles demand oxygen, and must have an adequate supply to burn fat and exercise aerobically. Each muscle is like a factory composed of thousands of muscle cells who do the work. Unlike some factory workers, these are passionate and dedicated team members ready to work 24/7 to keep us moving—even when we push them too far over and over again. Running, even in short amounts, done slowly, calls them into action, stimulates them to go to exhaustion, and serves to mold them into a team.

Endorphins kill pain, make you feel good

Another important member of the team, the endorphins, manage the muscle pain and provide a positive lift.

What is endurance exercise?

The essence of endurance is to go farther—to keep doing an exercise long enough, so that the body must find more efficient ways of moving, of processing energy, sending blood, etc. For untrained muscles, a run-walk of 10 minutes will do this. As we push back this threshold, our goal is to get to 2 sessions a week of 30 minutes each, with a long one that pushes up to the current endurance limit or beyond (more than 30 minutes).

Long one once a week pushes back the endurance limits

+

Two 30 minute sessions which maintain the adaptations gained on the long one

=

You the endurance athlete.

Stress plus rest produces improvement

When we run and walk a little farther than we’ve gone in the past month or so, this gentle stress breaks down the muscle cells, tendons, etc. Our bodies are programmed to rebuild stronger than before if you have enough rest afterward (usually 48 hours), so that the rebuilding can take place.

It all starts by gently stressing the system

When we exercise about every other day, our body becomes adapted to the speed and distance currently done. To improve endurance, we start by doing a run-walk that is slightly longer than we have been doing. As you exceed the current distance limit, tired muscle fibers keep working beyond their capacity. The extra work of an additional half mile or mile may not be perceived during the longer run, but produces after-effects the next day: sore muscles, a longer time needed to feel smooth when walking, and muscles that feel tired.

Looking inside the cell, afterward, you’ll see tears in the muscle cell membrane. The mitochondria (that process the energy inside the cell) are swollen. Glycogen (the energy supply needed for the first 15 minutes of exercise) is significantly reduced. There are waste products from exercise, and even bits of muscle tissue, and other after effects from a hard effort. Sometimes, breaks in the blood vessels and arteries occur with leakage of blood into the muscles.

The body rebuilds, stronger and better than before

Gentle overuse tells the body that it must improve. The damage to the muscles caused by going slightly beyond capacity is not only repaired, but the whole system is challenged to become more efficient so that more stress can be handled in the future.

If you have rested well, and look inside the cell again 2 days later, you’ll see thicker cell membranes, so that they can handle more work without breaking down. The mitochondria have increased in size and number, so that they can process more energy next time. The damage to the blood system has been repaired. Waste has been removed. Over several months, after adapting to a continued series of small increases, more capilliaries (tiny fingers of the blood system) are produced, improving and expanding the delivery of oxygen and nutrients and providing a better withdrawal of waste products.

These are only some of the many adaptations that the incredible human body makes, at all levels, when we exercise: bio-mechanics, nervous system, strength, muscle efficiency and more. Psychological benefits follow the physical ones.

You are becoming part of the process of improving health and performance, which produces a positive attitude. Mind and body are connecting up for great teamwork. These are only some of the reasons why runners have been shown to be more positive people than they were before they became runners.

Quality rest is crucial: 48 hours between workouts

Without sufficient rest, the rebuilding will not proceed as quickly, or as well as it could. I’m not talking about staying in bed all day after a workout. If you have run a hard workout in the morning, you’ll actually recover faster if you gently walk around the rest of the day. The day after a run, it’s usually fine to perform gentle movement, as in walking. There are other options for easy days in the chapter on cross training.

The key to rebuilding stressed muscle cells is to avoid exercises that strenuously use the calf muscle (stair machines, step aerobics, spinning out of the saddle) for the 48 hour period between running workouts. If you have other aches and pains from your individual “weak links”, then don’t do exercises that aggravate them further. As long as you are not continuing to stress the calf, most alternative exercises are fine.

If you don’t have time on the non-running days to do the alternative exercise, don’t feel guilty. Cross training is not necessary for running improvement. Why do it? Well, it helps those who want to burn more fat. Also, many new runners like the way they feel after running, and want to feel that way every day. Even running 2 days in a row produces significant damage, and requires much more recovery than an every-other day run schedule. Once you find the cross training mode that works best for you, you can enjoy the post exercise glow every day.

Junk miles

Some beginners feel so good when they start a running program that they “sneak in” a few miles on the days they should be resting. They often lie to themselves, assuming that this short distance isn’t really running.

The problem is that these short runs, which improve your conditioning, don’t give your muscles the rest needed for maximum recovery. They are called “junk miles.” It’s always better to stay with a 48 hour period between runs—the standard, proven recovery interval. With gentle increases, as noted in the training programs in this book, your body should rebound stronger than before, ready for a new challenge.

Regularity

To maintain the adaptations, you must regularly exercise every 2-3 days. Waiting longer than this will cause a slight loss in the capacity you have been developing each day. The longer you wait, beyond 3 days, the harder it will be to start up again. Staying regular with your exercise is the best policy.

“Muscle memory”

This is the process by which your neuro-muscular system remembers the patterns of muscle activity which you have done regularly over an extended period of time. The longer you have been walking and running regularly, the more easily it will be to start up when you’ve had a layoff. During your first month of running, for example, if you miss 3 days of running, it will take a week to get back to the same level, and feel the same way. But, if you have run regularly for 6 months, and you can’t run for three days, you won’t notice hardly any interruption in your running.

Tip: Cramped for time? Just do 5 minutes

The main reason that beginners don’t make progress is that they don’t run regularly. Whatever it takes to keep you getting out there, even for 10 minutes, three days a week—do it! Yes, even as little as 5 minutes will maintain some of the adaptations. If you do 5 minutes, you will do 10 on most days, and that will maintain most of the adaptations.

Difference between aerobic and anaerobic exercise

Aerobic means in the presence of oxygen. If you are running aerobically, you will be running slow enough to be within your current capabilities, so that your muscles can get enough oxygen to process the energy in the cells (burning fat in most cases). The minimal waste products produced during aerobic running can be easily removed.

Anaerobic running means going at a pace that is too fast or too long for you, putting you outside of your trained range. Your muscles can’t get enough oxygen to burn the most efficient fuel, fat, so they shift to the stored sugar, glycogen. The waste products from this fuel pile up quickly in the cells, tightening the muscles, and causing you to breathe heavily. If you keep running an aerobically, you will have to slow down significantly or stop. Anaerobic running requires a lot longer recovery period.

Fast-twitch or slow-twitch

Why are some people able to run fast, and others slow and steady for the duration? Several decades ago the mystery was solved through research on muscle fibers: those with more fast-twitch fibers can pick up speed quickly for a short distance. Those with an abundance of slow-twitch fibers won’t run fast, but can keep running and walking for long distances. Since you are born with one or the other, you may thank your birth parents for the type you have.

Fast twitch fibers are capable of explosive action followed by exhaustion, which can get us into trouble. Once these muscles get in shape, it is easy to go faster at the beginning of a run than you should—without feeling that it is too fast. Most fast twitchers can’t understand why they “ran out of gas” at the end of a run because the pace felt so easy at the beginning. The preferred fuel for fast fibers is glycogen (stored sugar). It burns quickly, produces a significant amount of waste, and then is fatigued.

The good news for those with the fast fibers is that longer long runs can adapt these to work as slow twichers. As you extend the length of your long runs, the muscle fibers are recruited, and transformed to burn fat. The most difficult part of long distance training for a fast twitcher is the slowing down of the pace from the beginning of a run. But, once the pace is controlled (and the ego), fast runners find that they don’t get exhausted at the end, and significantly push back the endurance limit.

Slow-twitch fibers burn fat naturally, and are, therefore, designed for aerobic endurance exercise. But, unlike fast-twitch fibers, the fat burners cannot be trained to fire quickly to allow for fast running. So, slow twitchers shouldn’t count on winning a race by sprinting at the finish.