Tour De France 2008 and Increasing Aerobic Capacity
Thursday, July 17, 2008
Jolie Bookspan, M.Ed, PhD, FAWM
The Tour de France is a 23-day bicycle race. This year it runs from July 5 to 27, 2008. It is a stage race, broken into individual races, from one town to another. The number of stages has varied over years since the tour began in 1903. Course distance runs approximately 3,000 km (1,864 mi) through most of France and often through one or more adjoining countries.
The synthpop song "Tour de France" was a 1983 hit single by the German group Kraftwerk. They put the motto of France in krautrock (krautrock is considered a fun and positive term by enthusiasts): Liberté, égalité, fraternité, French for liberty, equality, good company.
The Tour de France is a difficult event. Even with light bicycles designed for each stage, it is still grueling. Athletes must train for exceptional aerobic ability.
Cardiovascular endurance, also called aerobic capacity, determines how long you can continue activity at your chosen pace. When you exercise, your body needs more oxygen, so your cells extract more of the oxygen your blood provides. Aerobically fit people can extract more oxygen when exercising, and so, can do more exercise. Average exercise needs about 10 times more oxygen supplied to your active tissues, than at rest. Heavy exercise can increase need to around twenty times. If you do not have high enough capacity from training, you will be too out of breath to continue. World-class athletes have been recorded to reach over 30 times their resting rate.
With regular endurance activities, such as biking, running, swimming, your body makes many changes that improve function. You increase blood volume, the number of oxygen-carrying blood cells, expand the network of blood vessels, reduce incidence of vessels clogged with fatty deposits, increase number of cellular organelles and enzymes your body uses to process oxygen into energy, and other physical improvements, to be covered in future posts.
Breathing in more oxygen won't increase your ability to extract more oxygen. For that you need training. When your body senses it needs more oxygen than it is getting - during hard aerobic exercise or exposure to altitude - the kidneys secretes a natural human hormone called erythropoietin (EPO). EPO stimulates the bone marrow to make more red blood cells. Everyone can do this on their own through regular aerobic training. When some people want more EPO, they may try blood transfusions, called Transfusion Doping, an illegal procedure to increase maximum oxygen carrying ability. They may also inject various kinds of synthetic human erythropoietin. Whether having the money and access to these substances is fair play is topic of many debates in sports ethics. More important is that they are not healthy. Blood can thicken and cell count increases to a dangerous level leading to cardiac problems. Deaths have occurred in young athletes from blood doping practices. There have been experiments with artificial oxygen carriers based on recombinant, bovine (cow), and human hemoglobin or perfluorocarbons. These substances have potentially lethal side effects including renal toxicity, increased blood pressure, and immune depression. Champions don't need them. You don't need them.
Posts to come will cover more on performance enhancement, drugs, supplements, Le Tour and other bike races, The Olympics and other events. Posts on supplements and performance enhancing drugs:
Here is Friday Fast Fitness - How to know what heart rate will give you a cardiovascular training effect.
Several formulas calculate exact heart ranges and "target heart rates." There are a variety of commercial (expensive) heart rate monitors. Arguments in sports medicine continue on which is the right formula and if heart rates in water or at elevation can be calculated the same way. These issues will be covered in posts to come. For now:
Your body is smart. Heart rate generally follows "perceived exertion." If you feel your running or other exercise pace is moderate, your heart rate is likely to be at a moderate training range. If it feels light, then heart rate will likely be too low to give much training effect.
Find something you enjoy enough to continue more than ten minutes at a time.
Keep a pace that you feel is moderate to hard, depending how you like it.
If your running or other exercise pace feels moderate, it is also moderate for your cardiovascular system. If it feels hard, your heart and body and mostly likely working hard for your current level If it feels light, then it is too light to give much training effect.
Reader Mike sent this flawless Canadian commercial showing lack of exercise as a mindset. Have a laugh:
The commercial is for a company that sells products, but the message is right. A few years ago I was attending a major sports medicine conference. In the Grand Hall, was an escalator next to stairs. Both went to the same place. An easel with a plainly marked notice stated that a study was going on of exercise habits. Even with the written notice, by the end of the study, which consisted of a student sitting and counting, few took the stairs. Sports medicine professionals were overwhelmingly taking the escalator on their way to major presentations on disease consequences of sedentary behavior, and exhibit halls selling pedometers.
Fitness as a lifestyle isn't going to exercise class a few times a week. Check your mindset, and how you bend, lift, and move all day:
Respiratory Muscle Training for Swimming, Diving, and Running
Friday, July 06, 2007
Jolie Bookspan, M.Ed, PhD, FAWM
The previous post on training breathing muscles - Respiratory Muscle Training for Better Health and Exercise - covered how breathing exercises have been found to help increase respiratory capacity in people with various diseases, and more recently, to help physical training in athletes. At the diving and hyperbaric conference three weeks ago, I attended sessions on respiratory muscle training for underwater operations. It is a topic of interest for those in charge of combat swimmers.
In one study, Researchers at the State University of Buffalo at New York found that respiratory muscle training improves swimming and respiratory performance at depth. As you go deeper, the work of breathing can increase, even using high performance breathing devices, because of higher gas density and other factors. They tested the effect of resistance respiratory muscle training on respiratory function and swimming endurance in divers at 55 fsw (~16 m). They found that respiratory muscles were less fatigued following training, breathing rate was lower during the swims, and that the training increased the duration they could swim by about 60%. They concluded that respiratory muscle fatigue limits swimming endurance at depth, and the increase in swimming endurance may result from reduced work of breathing or improved respiratory muscle ability.
The second study by the same group looked at the different benefits of training the endurance and strength of the respiratory muscles. Eighteen SCUBA-certified swimmers were randomly assigned to a placebo group who didn't train their breathing muscles, a respiratory endurance training group, or a respiratory strength training group. Each group used a breathing resistance device five days a week for 30 min over four weeks. The endurance trained group decreased heart rate and ventilation during underwater swims. Both the endurance and strength groups improved fin swimming endurance. The placebo group experienced no changes.
The researchers concluded that respiratory muscle training is effective in improving swimming endurance. They told me they found it is also effective for endurance running, but perhaps not as effective. They are working on finding out why. My friends who do long stints in submarines mentioned they like to use respiratory muscle training to help keep them in shape since they can't go out for a run while on sub duty.
Respiratory Muscle Training for Better Health and Exercise
Monday, July 02, 2007
Jolie Bookspan, M.Ed, PhD, FAWM
At the American College of Sports Medicine conference last month, I attended an entire session on effects of training respiratory muscle function. Back when I was in school, we learned that the ability to breathe harder, better, faster, could not be trained with exercise or other modality, that it was fixed from person to person, like eye color, except that it got worse with aging, and that it didn't matter much, since ventilation did not do much to limit exercise potential anyway.
Even though the lungs don't have any muscles of their own, it didn't seem right to me, as the diaphragm and muscles that move the rib cage to voluntarily breath in and out are muscles like any other. What if there are people whose respiratory muscles are not trained to work hard enough and add to the metabolic cost of exercise, increasing fatigue and so, limit exercise? It is also true that many people are not in good enough shape to use more oxygen, so breathe most of the oxygen back out with each breath, even when exercising strenuously. What about someone in great athletic shape who could use that oxygen. Why couldn't they be trained to move more air faster if they needed some?
Exercising the muscles that you use to breath in (inspiratory muscle training) is known to improve the endurance of the respiratory muscles in people with spinal cord injury and cystic fibrosis, and is shown to improve exercise capacity in patients with heart failure. What about for people without these conditions or for athletes?
The diving medicine conference two weeks ago had several studies that showed interesting and promising results with breathing training. Combat swimmers have long used various breathing training to get in shape for swims and other strenuous work. The next post covering respiratory exercises - Respiratory Muscle Training for Swimming, Diving, and Running - tells about it.
Respiratory muscle training in the above studies did not involve popping corks from your lips, as in the accompanying photo. To improve your breathing capacity and do training at home without respiratory training devices, see the post Do Breathing Exercises Work? and the book Healthy Martial Arts.
Exercise and Fitness in Decompression Sickness Risk
Sunday, June 17, 2007
Jolie Bookspan, M.Ed, PhD, FAWM
In the post Train Exercise is Exercise Training I mentioned the ongoing question in diving physiology research of how exercise can affect the risk of decompression sickness (the bends).
It seems that exercise done during a scuba dive at the bottom increases the amount of nitrogen gas you absorb from the air you breathe from your tanks. This makes more gas which could contribute to decompression sickness on the way up. Mild exercise on a "decompression hang" (waiting at specific shallower depths for a few minutes on the way up) seems to help let more gas dissolve out while you breathe, and may lower risk. Exercise soon after surfacing may increase gas coming out and increase risk according to other work. Some interesting studies look into whether exercise done days before a dive can reduce risk by "using up" specific components that decompression sickness bubbles need to be able to form. The kind of exercise and timing seems important. I will post more on this another time.
Some work looks at physical fitness, and whether that affects risk of decompression sickness (DCS). Would someone in better physical shape have lowered risk? What constitutes being in better shape? Is it body fat? Is it the amount of oxygen you can use to exercise? How might any one of those components affect DCS risk?
Here at the UHMS scientific meeting, one of the studies presented by French naval researchers is, "Does the VO2 max value predict the formation of intravascular circulating bubbles during decompression of healthy divers?" VO2 max (pronounced vee-oh-too-max) is the most oxygen you can use when doing the most exercise you can do. It is usually higher in people who can do more aerobic exercise (other factors also contribute). The maximum amount of exercise an average person can do is about ten times their resting level of oxygen use. Marathoners usually max at around 20 times better than resting levels. A top aerobic athlete can use about 30 times resting level (a horse - more than twice the top human max). Someone badly out of shape, or with heart disease or other problems that limit ability to get oxygen to cells, generally has a low VO2 max. You can raise your level with regular exercise at any age. It is not set.
In the French study, divers were tested for VO2 max a week before their experimental dive. They avoided any physical exercise 48 hours before the dive. Then half completed a dive in a dry hyperbaric chamber and the other half in the open sea with the same dive profile and decompression stop according to French military decompression table MN90. After the dive they were all tested for presence of small decompression bubbles in the bloodstream.
Bubbles can form in the body painlessly after a dive without creating decompression sickness. It is not the case that bubbles always form after every dive, as often thought. Certain bubbles can be detected audibly (they sound like pops and squeeks) using Doppler ultrasound, and other kinds of instruments being developed. I will post more another time about these bubbles and what ultrasound can and can't determine about bubbles and decompression sickness.
The French researchers found that bubble formation in both types of dive was related to the age and body mass index of the divers, but not to VO2max.
Being in good shape makes many aspects of diving safer, even if it doesn't affect risk of decompression sickness. Being in better aerobic shape helps you swim more easily against currents that may take you away from your dive site or boat. Strengthening your body through weightlifting with good body mechanics helps you lift and haul gear with less chance of injury, and practicing all your physical skills helps you be more able to rescue someone or yourself.
What about physical fitness and risk of decompression sickness in space? Several studies here at the meeting address that. Astronauts who go outside the space vehicle go to lower pressures, similar to divers coming up from a dive. Many considerations, including exercise, go into their preparation for that. The interesting story is posted in Space Walks.
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