"Helping You Become Your Best"
Articles
SPECIAL REPORT
Your Heart Rate
By: Beth Dean, CPT
Your heart is a marvelous device. It works nonstop day after day for years. Its endurance capability is amazing. Try using any other muscle in your body in the same way and what happens.
Since the heart is a muscle it can become larger and stronger through exercise that progressively increases the body’s demand for oxygen. This type of exercise is called aerobic exercise. Aerobic energy production requires a constant and adequate supply of oxygen. The respiratory and cardiovascular systems transport the oxygen.
One common term used in relation to heart rate training is stroke volume. Stroke volume is the volume of blood pumped out of the heart per heartbeat. With endurance exercise the heart becomes bigger and is capable of delivering more blood per beat to all the waiting muscles of the body. Fit athletes will have higher resting stroke volumes and lower resting heart rates. In comparison an untrained person’s heart rate may be about 70 beats per minute at rest, as in endurance athletes it may be in the 30’s or low 40’s.
During exercise, the amount of blood pumped by the heart must increase to match the increased demand of the working muscles. It regulates this by matching heart rate to demand through a feedback loop. That is the more intensely you exercise the higher your heart rate goes. This is why we monitor heart rate to help gauge the intensity of exercise. Just as with resting heart rate, as your aerobic fitness develops, your body’s ability to pull oxygen out of the blood improves and so your heart rate decreases at any given level of work output. This drop in exercise heart rate is another good indicator of improving aerobic fitness.
FACTORS THAT CAN INFLUENCE YOUR HEART RATE
You can expect many influences to affect your heart rate. Knowing these can help you prevent those that are avoidable as you train. Research has shown a daily variation in heart rate of 2 to 6 beats per minute at the same workload. This is because we are humans and not machines!
A rise in body temperature causes an increase in heart rate. Humidity has the same effect as heat. The heart is working hard to cool the body and fuel the muscles. Gravity can affect your heart rate as well. A good example of this is running in water. When the body is buoyant and gravity is reduced the heart rate does not rise nearly as fast.
Poor technique wastes a tremendous amount of energy, which is associated with a higher heart rate. A runner who bounces, or a cyclist who sways will work harder. This is an area where most amateur athletes can improve.
Over the counter and prescriptive drugs can affect heart rate. Drugs such as diuretics can decrease heart rate. Medicines like cold remedies are likely to raise it. When taking some drugs it is best not to exercise at all. It is wise to consult with your doctor about how wise it is to exercise and what the drug’s side effects might be.
Women tend to have a slightly higher heart rate than men. This is simply because they often are smaller and have a somewhat smaller heart. Since the heart is smaller is pumps less blood per beat and therefore has to beat faster to deliver oxygen and fuel to the muscles of the same workload.
TWO COMMON MISCONCEPTIONS
1. To lose weight, exercise in the “fat burning zone”.
It is true that when you exercise at a low intensity your primary source of fuel is fat. So why isn’t going slow always the best answer to shedding unwanted fat.
The answer lies in how many calories you burn during low intensity and high intensity exercise. When you are going slow fewer calories are used per unit of time. For example two 150 lb people each exercise 30 minutes. One walks two miles and burns about 200 calories. The other runs three miles and consumes around 330 calories. (70% of the cal. were from fat –140 cal. for the first person, and 60% -198 cal. for the second person.)
Another factor is that from the time after the workout a few minutes to a few hours you metabolism is elevated. The higher the intensity and greater duration of the workout the higher the metabolism and more calories burned.
2. The purpose of training is to increase heart rate.
Some athletes believe that the purpose of training is to make their hearts beat faster. Over time they want to see higher heart rates when they work out.
The purpose should be to get more output (pace) for the same input (heart rate). What you would actually like to see is that your heart rate gets lower over time, or that you get faster at the same heart rate. If your time improves even though your heart rate and effort stay the same then your fitness is improving.
Resources for this article:
Friel, Joe, Total Heart Rate Training, 2006, pg. 21-35.
National Academy of Sports Medicine, Cardiorespiratory Training for Fitness Goals, pg. 7-12.
Look for additional information and articles in the future on this site at www.bethdeantraining.com
Or you may contact me at 651-308-4814 for questions or comments.
Fat Burning Q&A
By Beth Dean, CPT
How does aerobic exercise burn calories?
Aerobic exercise requires the body to take oxygen. The oxygen is eventually pumped to the working muscles where it is utilized to oxidize carbohydrates and fats to produce energy (ATP).
During prolonged exercise, more than 99% of the energy required is generated by aerobic reactions. Thus one of the most important characteristics of aerobic energy is the ability to utilize stored body fat as a primary source of energy.
Is low–intensity exercise better for fat burning?
We have all heard claims that the best type of cardio training for burning fat is the so-called “fat burning zone”, which is a low intensity. Studies have confirmed that at lower intensities a greater percentage of energy comes from fat than at higher intensities.
However, as long as workouts are the same length, the total energy expenditure (calories) will be greater and a person will burn at least as many fat calories if not more at a higher training intensity. In other words the selective use of fat as fuel that occurs as a low intensity exercise does not translate into greater fat loss.
The higher the intensity the body can train at while remaining aerobic, the greater the number of calories burned from fat. One of the main goals of cardio training is to increase anaerobic threshold ( this is the intensity at which adequate oxygen is unavailable).
Does cardio exercise make you a better fat burner?
Yes, below are some of the ways cardio exercise enhances fat metabolism.
• An improved oxygen system helps cells burn fat more efficiently.
• Sensitivity of muscle and fat cells is enhanced, leading to improved release of fatty acids.
• The amount of fatty acids allowed to enter the muscle increases, making more fat available for fuel.
• The mitochondria, sometimes referred to as the cells “fat burning, furnaces”, increase significantly in number and size.
• The enzymes that speed up the breakdown of fatty-acid molecules to be used during aerobic exercise increase.
Does strength training factor in?
Yes, one of the most important benefits of strength training is the preservation of muscle mass, even on very low calorie diets. It is also, one of the best protective methods to maintaining your resting metabolic rate during a calorie restricted weight loss program.
The fat burning solution: To burn more fat, burn more calories!!!
Resources for this article:
National Academy of Sports Medicine, Cardiorespiratory Training for Fitness Goals, , pg. 8 & 18.
IDEA Fitness Journal, September 2007, pg. 23-24, “Fat facts”, by Len Kravitz, PhD.
Look for additional information and articles at www.bethdeantraining.com
Or you may contact me at 651-308-4814 or e-mail BADean5@aol.com for questions or comments.
Want more information on changing your life? Call me at 651-308-4814