Tag Archives: endurance

Vacation is over…it’s time to get back to the gym.

Summer is winding down so many of us will be getting back to our usual routine. Maybe you had an active vacation this summer and maintained your fitness.  More likely, you took relaxing on your vacation a bit too seriously and fell out of your normal exercise routine.

Athletes have long known that even a short break from training results in significant decreases in fitness and performance. You may have noticed this yourself after taking time off. Two recent studies that you may have read about in the news suggest that taking time off from exercise can have a negative impact on your health.

Let’s explore how and why this happens, and what you can do to prevent it.

Exhausted after workout


When you start an exercise program your body adapts in ways that improve your strength and endurance.

Your aerobic fitness and endurance are enhanced by both cardiac and muscle adaptations. Your heart actually gets larger and stronger to pump more blood to your muscles. Within the muscles there is an increase in the number of capillaries, the small blood vessels that deliver blood to the muscle, and mitochondria, the part of the cell that produces ATP, the energy the muscle uses to contract. Together, these adaptations allow the muscle to produce more ATP without fatigue, allowing you to exercise a higher intensity for a longer time without fatigue.

If you do resistance training (and you should!), you get stronger and your muscles get bigger, called hypertrophy. Lifting weights causes microscopic damage in the muscle, which leads to inflammation and soreness. This sounds bad, but your muscles respond by rebuilding stronger, allowing you to generate more force and causing the muscle to grow in size.

These adaptations are also a major reason that exercise makes you healthier, too. Your blood pressure, blood glucose, and blood cholesterol are all improved because of how your heart, blood vessels, and muscles respond to exercise. Additionally, exercise results in changes to certain hormones and how your body stores and uses or stores glucose and fat. The end result is that exercise has far-reaching beneficial effects on your health that simply can’t be matched by any other intervention, including medications.

So, when you stop exercising for a period of time you start to lose these adaptations. This causes both your fitness and health to decline. And it happens quickly, in as little as two weeks!

Two recent studies demonstrate that regularly active adults who suddenly limit their usual activity for two weeks experience significantly impaired blood glucose control, increased fat storage, and lower fitness. It is important to note that in both studies these changes did not fully return to baseline after resuming normal activity for an additional two weeks. This means that the benefits of exercise were lost quickly and took a longer time to return to normal.

This is also true for aerobic fitness and muscular strength. Research done on athletes who stop training, perhaps due to an injury, shows that fitness declines rapidly with the first two weeks. Worse, it can take many more weeks to regain those fitness losses. You may not be a competitive athlete, but the same principle applies to you when you take time off from exercise.

Make it your goal to maintain some level of activity, even when you are on vacation. Time off can mean doing less, but it doesn’t have to mean doing nothing. Even a little exercise can help you maintain your fitness, keep you healthy, and make it easier when you return to the gym.


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Santa’s exercise plan for functional fitness and health

Since Christmas is only a few days away our attention is naturally focused on one person: Santa Claus. Have you ever wondered how Santa gets in shape for his yearly sleigh ride to deliver gifts to good boys and girls around the globe? Like many elite athletes, Santa does not publicly discuss his training or his fitness. There are certainly no published studies that report his one repetition maximum strength or his maximal oxygen uptake. Given this lack of information, I attempted to make an educated guess about Santa’s training, fitness, and health. This is the topic of my Health & Fitness column in the Aiken Standard this week.

santa


By all accounts, Santa is overweight. While we don’t know his body mass index, he would probably be considered obese. Furthermore, he appears to have a large waist circumference, indicating a high level of visceral fat. This suggests that Santa is a high risk for type 2 diabetes, high blood pressure, and heart disease. This combination can lead to a heart attack and, possibly, death at a relatively young age.

But Santa has avoided this fate, and seems to be living a healthy life. His secret, no doubt, is regular exercise. There is good evidence that maintaining a high level of physical activity can “undo” some of the negative effects of obesity and can reduce the risk of death in people who are obese (and everyone else).

Like many athletes, Santa trains in the “offseason” to get ready for his annual Christmas Eve journey. Santa’s training likely includes endurance, strength, and flexibility exercises. In order to visit every home around the world in one night, Santa moves quickly. This suggests that he has a high maximal aerobic capacity as well as good endurance. This is a result of both high-intensity interval training and long-duration, lower intensity training, similar to what a marathon runner might do. Evidence for his good aerobic fitness is shown by the fact that he flies away from each home with a hearty “ho, ho, ho.” If he were out of shape, he would be too short of breath to speak, much less give such a robust farewell.

Santa must also dedicate training time to improving his strength. His sack of gifts is certainly very heavy and he repeatedly carries it up and down chimneys. In addition to traditional weight lifting, Santa probably also engages in plyometric training, which involves explosive movements that develop muscle power. Santa must also have good flexibility in order to squeeze through narrow spaces and move quickly without pulling a muscle. This is the result of stretching and, likely, other exercises such as yoga.

Santa is also educated about sports nutrition. The cookies and milk you leave for him are more than a reward for delivering gifts at your house. The carbohydrates (sugar) in the cookies help Santa maintain his blood glucose to delay muscle fatigue. Some research suggests that combining carbohydrates with protein is even more effective, so the glass of milk is a good addition. Of course, Santa could have a specialized sports drink, but that doesn’t make for such a good story.

We can learn an important health lesson from Santa. Even though he is overweight, through regular exercise, Santa has reduced his risk of health problems and maintained his fitness at a level that allows him to complete his necessary activities. Like Santa, all of us can benefit from being physically active, whether we are overweight or not. He would likely be healthier and be able to perform his job better if he lost weight, but I’m not about to tell Santa what to do!


Nutrition, exercise, and health information can be confusing. 
But it doesn't have to be that way.
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 drbrianparr@gmail.com | http://twitter.com/drbrianparr

Sports Science in the News: The 2-hour marathon

There was a great article in the New York Times recently about a sports scientist who is on a quest to train a runner to complete a marathon in under two hours. Even though the world record right now is just under 2 hours and 3 minutes, a sub two-hour marathon is a bit like the four-minute mile once was—many people think it is impossible (or at least not likely to happen anytime soon). What I appreciated about the article was the way it explained some key concepts in exercise physiology. Since I am preparing to teach my summer Exercise Physiology course in June, I thought this was particularly relevant and worth sharing in my Health & Fitness column in the Aiken Standard this week.

Marathon feet


First, let’s put a two-hour marathon in perspective. To do it would require sustaining a running speed of over 13 miles per hour for two hours! Most runners I know would be hard pressed to complete the 285 yards at that pace…forget about the 26 miles that come first. It is also more than twice as fast as the average marathon time of over 4 hours. If you are brave you can see how fast this is yourself by getting on a treadmill and cranking the speed up to 13 miles per hour. Hang on, though, because you won’t last long!

The article mentions the training method known as “live high, train low.” This technique involves athletes spending time at high elevations but doing much of their training at sea level. This works because the key to endurance performances like a marathon is getting as much oxygen as possible to the muscles to use to produce energy. Living at high altitude causes the body to produce more red blood cells, increasing oxygen delivery to the muscles. But because there is less oxygen in the air at altitude, athletes can’t train as hard, which may offset the gains in red blood cells. Because of the lower training intensity, which is essentially doing less work, some athletes realize little benefit from this technique. So, a perfect solution is to live (or spend lots of time) high, but train low to maximize the benefits of both altitude and intense training.

The article also mentions another interesting phenomenon related to oxygen delivery to the muscle. As the heart pumps blood to the muscles it also sends blood returning from the muscles to the lungs to pick up oxygen from the air we breathe. As the red blood cells pass by the air sacs of the lungs (the alveoli), oxygen molecules bind so that the blood is fully saturated with oxygen before it is pumped back to the muscles. But the harder the heart beats during exercise the faster the blood flows. In some elite athletes, the blood flows so fast that the red blood cells don’t have enough time to pick up enough oxygen. This can reduce oxygen delivery to the muscles and impair performance in these athletes. (Fortunately, it isn’t a problem for the rest of us)

Admittedly, I am a bit of a physiology geek, so this is fascinating to me. If you are curious about exercise physiology and sports performance, check out the New York Times article from May 11—it’s a sneak peek into the world of sports science. The article also touches on nutrition, especially carbohydrates, biomechanics, temperature regulation, and training as important factors in reducing marathon times. All of these are topics that I cover in my Exercise Physiology course, too. And in case any of my students are reading this—yes, it will be on the exam!


Nutrition, exercise, and health information can be confusing. 
But it doesn't have to be that way.
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A one minute workout?

You have probably heard of people who do very short workouts—sometimes just a few minutes—but still get the same benefits as you do going for a long run or sweating through an hour on the elliptical machine. This type of exercise is called high-intensity interval training (HIIT), which involves short bouts of very intense exercise separated by periods of rest or light activity. I have written about this type of training previously (and before that, too), but a new study that has been in the news this past week makes revisiting this topic worthwhile.

Cycling class


Previous research has shown that shorter exercise sessions can be as effective as the typical 20-60 minutes of continuous exercise people commonly do to lose weight or get in shape. The catch is that these shorter bouts of exercise must be done at a very high intensity to promote improvements in maximal exercise capacity (called VO2max) and endurance by enhancing heart function and causing changes in the muscle itself. These adaptations can lead to improved fitness, performance, and health.

For example, in one study the intervals were as short as 30 seconds of all-out, maximal exercise separated by rest periods, for a total of just six minutes of exercise per day. Other studies employ slightly less intense intervals for a total of 20 minutes of exercise per session. Another study found that a single 4-minute bout of vigorous exercise was effective. Taken together, these studies show that HIIT leads to adaptations in the heart and muscle and improvements in VO2max and endurance that are greater than that of more traditional, lower intensity exercise.

A new study published last week ( excellent low-sci description here) showed that sessions of one minute—yes, 60 seconds—of intense exercise can match the fitness and health benefits of more traditional workouts. Subjects in the study completed three, 20-second bouts of all-out, near maximal exercise separated by two minutes of light cycling on a stationary bike. After doing this three times per week for 12 weeks the changes in heart rate, muscle function, and blood glucose regulation were the same as those experienced by subjects who did the same number of 45 minute workouts, but at a lower intensity.

Before you get too excited about only needing to exercise for a minute at a time, there are a few points to keep in mind. First, this type of exercise is very intense and may not be right for everyone. At the very least, it is likely to be uncomfortable. Second, exercising at a high intensity may not be a good idea if you are not already in good shape or have other health problems, like high blood pressure. Third, HIIT may not be the best way for you to meet your exercise goals. If you are trying to build endurance for a marathon or long distance bike ride, you really do need to focus on longer duration exercise at least some of the time.

Finally, if you add up the total exercise time, including the warm-up, time between intervals, and recovery, the “one minute” workout is more like 10 minutes of exercise. This is still shorter than what you would probably do anyway, but certainly not a true 60 second workout. And this type of training doesn’t do much to help you meet other fitness goals including improving strength and flexibility, so you will still need to spend additional time in the gym. The bottom line is that HIIT should be part of your exercise regimen, not the whole program.


Nutrition, exercise, and health information can be confusing. 
But it doesn't have to be that way.
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 drbrianparr@gmail.com | http://twitter.com/drbrianparr

Start making deposits in your fitness bank

Saving money for emergencies is good advice and important for maintaining quality of life in the event of a lost job or other financial crisis. While this may seem like common sense, many people have been caught without enough savings when they needed it and found it difficult to meet basic needs.

This principle can also be applied to fitness. When you are healthy, you can maintain a high level of fitness. This makes your day-to-day activities easier and serves as a reserve or “bank” to draw on when you need it. Your good fitness now can get you through a health crisis just like saving money can help you through a financial crisis. This health crisis could come in the form of an injury or illness that keeps you from being active for several days or a hospitalization that keeps you in bed for a week, a month, or longer. This is the topic of my Health & Fitness column in the Aiken Standard this week.

The problem with periods of inactivity, like bed rest or hospitalization, is that there are severe physiological effects that occur within days and get worse over time. You may have noticed this as weakness and fatigue after spending a few days in bed with a cold. Muscle strength declines at a rate of over 1% per day of bed rest, and can be 50% lower following as little as three weeks. That 50% reduction in strength could limit a person who was already deconditioned to a point where he or she would have difficulty completing the most basic activities of daily living.

A person who was fit and strong when they went into the hospital would certainly be better off when released. And older adults fare worse than younger individuals. According to one study, the decline in strength seen in older men in just 10 days was equivalent to the change measured after 28 days in men 30 years younger.

It’s not just the muscles that are affected, the bones get weaker, too. In fact, 12 weeks of bed rest can reduce bone density by as much as 50%, exposing patients to a greater risk of fracture. This is due to the reduced stress on the bone from not standing and walking as well as the lack of muscle activity. Two of the most effective ways to build bone density are putting stress on bones through weight-bearing activity and the action of the muscles pulling on the bones from resistance training. Because bed rest eliminates both of these stresses, bone density declines rapidly.

One unique study had healthy young men complete three weeks of bed rest back in the 1960s. They all experienced a rapid decline (over 20%) in their aerobic fitness, but recovered quickly after the experiment ended. These individuals also had their fitness tested again 30 years later. It turns out that the decline in fitness in those young men in three weeks of bed rest was greater than the decline in fitness that occurred over 30 years of aging!

The good news is that most patients are encouraged to move around as much as possible. Some receive in-patient physical therapy or rehab, even after major surgery, to help lessen the effects of prolonged bed rest. It is important to take advantage of these opportunities if you, or a loved one, are hospitalized.

There are many reasons to exercise and be fit, but the most important reason may be to develop a fitness “bank” you can draw on if you become injured or hospitalized. Since the effects of bed rest are seen in people of all ages, everyone can benefit from a good fitness foundation. Just like putting money in the bank, doing a little now can have great benefits later when you need it most.

Finally, some smart advice: First, achieve and maintain a high level of fitness now, just as you would save money for a rainy day. You never know when you will need it. Second, if you are hospitalized, take advantage of opportunities to move, whether that is limited to moving from bed to a chair or if it includes short walks or even inpatient exercise–if the medical staff approves, of course. While many well-meaning friends and family members will tell you to rest and not move, true bed rest is almost the worse thing you can do.

For example, inpatient cardiac rehabilitation targets patients who are recovering from heart attacks and even open heart surgery. The goal is to get these patients up and moving as quickly as possible to prevent long-term consequences of bed rest.


Nutrition, exercise, and health information can be confusing. 
But it doesn't have to be that way.
What can I help you with?
 drbrianparr@gmail.com | http://twitter.com/drbrianparr