Both Bigg Hoss and a normal person would have approximately the same fuel cost at rest (5 liters per minute) but it takes Bigg Hoss almost twice as many beats per minute to get the same fuel pumped. One more chart to really get to the crux of the problem. A normal person would be sitting at about 35% max capacity at rest but Bigg Hoss was at nearly 70%! Blue represents the cost at rest and orange represents the reserve capacity. Bigg Hoss would have the same max heart rate, but his resting heart rate was 135 BPM, so his reserve capacity would be 185 – 130 = 55 beats per minute. The normal persons reserve capacity would be 185 – 70 = 115 beats per minute. The normal person is sitting at idle (rest) with a heart rate of 70 and a predicted max heart rate of 185 beats per minute (220 – 35). Let’s assume we are comparing a “normal” person, who is 35 years old, with 35-year-old Bigg Hoss. We can loosely estimate maximum heart rate by subtracting 220 by age in years. An unfit person would tend to have the same (or even greater) maximum heart rate as a very fit person. But before we do, you need to know one more thing: Maximum heart rate does not decline with fitness. This reserve capacity is the excess capacity above and beyond sitting at idle (resting value). That is a reserve capacity of 20 liters per minute (25 liters – 5 liters = 20 liters). You can see in the table above that with the pedal to the medal (max exercise capacity), we are pumping 25 liters per minute. ![]() The reason that stroke volume increases is because during exercise, more blood is returned to the heart, so more blood is ejected with each beat. In our example it increases to a typical value of 135 ml. At rest it may be about 70 ml, but at max exercise it could almost double. It increases with increasing exercise intensity. ![]() However, stroke volume is not a constant. ![]() How about the cost to put the pedal to the metal? Again, this can be calculated by multiplying heart rate by stroke volume. If the heart rate is 70 BPM and the stroke volume is 70 ml, then the cardiac output would be 70 BPM X 70 ml = 4.9 liters per minute. The typical amount of blood pumped per beat (called stroke volume, the volume pumped per “stroke”) is about 70 milliliters. Typical resting heart rate is 70 beats per minute. Let’s look at the table below to gain a deeper understanding. For the body, the cost of sitting at rest is about 5 liters per minute. In a car the fuel cost of sitting at idle might be ¼ gallon per hour. Just like in a car, there is a fuel cost to sit at idle. In a car the fuel is gas, in the body it is oxygen. Think of the heart as a fuel pump and the muscles as the engine. Let’s build a theoretical car to help understand this concept, so that we can apply it to some practical uses. He was well on his way to burning up his engine (congestive heart failure). It was > 120 beats per minute! His throttle was at ¾ just sitting there! Like my 50cc scooter, he was very near max capacity just “keeping up with traffic.” He had very little reserve capacity for simple exertions like walking up stairs. Later I had a long discussion with Big Hoss about his health and I had a chance to measure his resting heart rate after he had fully recovered. His heart was racing, and he was breathing hard like he had just run a 10K. ![]() He had just walked up a single flight of stairs and was so winded he had to sit down for 15 minutes. Well, five minutes later Big Hoss walked in. He mentioned that I would be rooming that night with “Big Hoss” and that it would be an experience I would never forget! Turns out Big Hoss snored like a freight train. I was to present the class the next morning. On my first day, first oil platform, the manager welcomed me aboard. I had almost no reserve capacity! It took me less than a year to burn up the engine because I was full throttle almost all the time.Ī few years later I was working for a major oil company, delivering smoking cessation classes on offshore oil platforms. I had to crack the throttle to about ¾ max just to keep up with traffic on neighborhood streets. When I was 19 I had a 50cc Honda Scooter. We can use it to gain some insight into our reserve capacity. The reason it is such a good measure is because it is a good marker for our ability to do high intensity work. In this article, we’ll talk about heart rate reserve and some simple ways to use heart rate to demonstrate changes in fitness. It is a simple metric that is easily and cheaply measured, but its value by far exceeds the trivial cost and effort to obtain it.Īs an assessment tool for cardiovascular fitness, it’s hard to beat. You can learn a lot about a person’s fitness and training by observing heart rate.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |