Article by Tyler Norman from Life Long Learning November Newsletter
I hate it when individuals get discouraged with their workouts because they aren’t seeing results come fast enough. Losing patience with exercise is especially common when it comes to the boring and mundane act of cardiovascular exercise. Walking is one of the most common activities for retiree-aged individuals for recreation and exercise because it makes us feel better and it’s nice to get outside.
When trainers write exercise prescriptions for cardiovascular exercise, however, to just say “walking for 30 minutes” is too vague. A complete cardio prescription includes 4 variables: frequency, intensity, duration, and mode. You may have heard the phrase “target heart rate” – which refers to the intensity of your cardiovascular exercise. Before I get into that, remember why we are doing cardio. We either want to increase our aerobic endurance and heart health, which relate to the body’s efficiency at transporting oxygen, or we want to lose weight. This is where “target heart rate” comes into play.
Our bodies select fuel based on the stress we put on them. Most people think that if they want to get a good “cardio” workout they need to be sweating and have labored breathing. This is true if your goal is to improve your aerobic endurance and heart health. If you are exercising at that intensity, your body needs a fuel source that is readily available and easily utilized for fuel, so it chooses carbohydrates because they are easily broken down and are usually easily available (we tend to eat a lot of carbs). If you do cardio at a lower level of intensity, your body doesn’t need a fuel source that’s readily available or as easily utilized, so it selects an alternate fuel source – fat.
So, here’s the formula:
220 – age = estimated maximum heart rate
60 – 70% of estimated max heart rate for fat metabolism
75 – 85% of estimated max heart rate for aerobic endurance
Example for a 70-year-old:
220 – 70 = 150 estimated maximum heart rate
60 – 75% = 90 – 105 heart beats per minute for fat metabolism
75 – 85% = 112 – 127 heart beats per minute for aerobic endurance
So now that you know what target heart rate means you can tailor your workout specifically to your goals! Here’s the kicker – it takes the average person 15-20 minutes to get the core temperature of the body to a point where it starts to burn fat, which is when most people stop. I usually recommend a 45-minute duration for the lower intensity cardio and a 20- to 30-minute duration for the higher intensity. Frequency should be a minimum of three times per week.
To measure your heart rate during exercise, you can either get a heart rate monitor which usually costs about $100, or you can just take your own heart rate by monitoring your pulse. Five minutes into your cardio session take your heart rate for six seconds and add a zero to get your per minute heart rate – then adjust your workout intensity accordingly to get yourself into your target zone. As for the mode, it doesn’t really matter! Treadmill, bicycle, elliptical, swimming, rowing, alligator dodging, or roller derby are all good forms of cardio.
