February is Heart Month. (Valentine’s Day. Hearts. Get it?) All month long you’ll see and hear messages about heart health. Cardiorespiratory (cardio) exercise improves the ability of the heart, lungs, and circulation to deliver oxygen to the working muscles and for those muscles to use it. Greater cardio fitness lowers your risk for developing heart and vascular disease in the following ways:
- strengthens the heart muscle
- increases blood flow to the heart muscle
- usually lowers blood pressure
- often increases HDL (or “good”) cholesterol
- helps manage stress
- helps with weight loss and maintaining a healthy weight
- the standard of care for recovery from existing heart and vascular disease
Increasing Your Volume of Cardio
What do I mean by volume? Volume consists of Frequency (how often; in times per week), Intensity (how hard you work), Time (how long you exercise per workout), and Type (I’ll unpack this below). Together these form the FITT Framework (FITT). Let’s look at each of these factors. (They are presented in logical and physiological order of progression, different from the order in which they appear in the FITT acronym.)
The first thing to increase is frequency. The American Heart Association/American College of Sports Medicine Guidelines (Guidelines) call for 30 minutes of moderate-intensity cardio, on most days of the week. If you’ve done zero cardio for months, two to three times a week is a good start. If you do twice this week, can you do three times next week? Can you add one workout each week, until you’re up to 5 or 6 times a week?
The next part of the FITT is to increase is time or duration. If the first time you walked in your neighborhood or pedaled the stationary bike at the gym, you managed 10 minutes, can you make it 11 next time? Can you add one minute each workout, until you’re meeting the Guidelines’ recommended 30? (If weight loss is your goal, the Guidelines call for as much as 60 minutes daily at moderate intensity.)
The last part of the FITT to increase is Intensity. How would you know if you’re working hard enough? Certainly, for many, heart rate (HR) is a good indication of exercise intensity. Over the years I’ve seen many people whose HR response to exercise isn’t typical or predictable. Some medications used for high blood pressure or heart conditions, can reduce resting HR and maximum HR (eg, beta blockers). Formulas for calculating target HRs give numbers that are based on statistical norms. Even people not on medications can fall outside the norms. Still, it’s worthwhile to begin with the formula.
The formula I use (which replaces the old 220‒age) is 206.9‒(.67×age). For me at 59, this works out to a predicted maximum HR of 167. (My actual maximum HR is about 172.) Target HR ranges are based on fitness level:
Fitness Level %HRmax* RPE**
Poor 57% to 67% 10—13
Poor to Fair 64% to 74% 11—14
Fair to Average 74% to 84% 12—15
Average to Good 80% to 91% 13—18
Good to Excellent 84% to 94% 14—19/20
(*Percentage of Maximum HR; **Rating of Perceived Exertion [see below])
Using a recent client (I’ll call her Marge) as an example, her predicted maximum HR is 163 and her fitness level is Poor to Fair. Marge’s training HR range will be between 104 and 121. Given that she is starting to exercise for the first time, she can train within this range and get significantly fitter.
As Marge gets fitter, her HR will be lower at any given workload. When she started, her HR was 118 while walking at 2.5mph, at a 6.5% incline on the treadmill. After only six workouts, she must now walk faster and/or at a greater incline to achieve the same HR.
Rating of perceived exertion (RPE) is another way to gage exercise intensity. On a scale from 6 to 20, assign a number to how hard you’re working. Six is no exertion, sitting upright in the chair, doing nothing. Twenty is maximal exertion. Imagine sprinting up a steep hill, with a full pack, being chased by a drill sergeant, yelling at you to run faster. RPEs of 7 to 11 are (for most people) low intensity. It’s physical activity, but not likely exercise and suitable for warm-up and cool-down. Moderate to moderate-high intensity is from 12 to 16. Seventeen to 20 is the high intensity zone. As you become fitter, your rating of perceived exertion might change. A level of exertion you once considered Hard may seem less so.
A word about the other T, Type. Types of exercises can be divided several ways. First, we distinguish between weight-bearing and non-weight-bearing. Walking, running and step aerobics are weight-bearing, while swimming, cycling and rowing are not. Water aerobics maybe partially weight-bearing or non-, depending on water depth. All other things being equal, weight-bearing is usually more demanding. Second, we think of upper-body, lower-body and whole-body exercise. Pedaling a stationary bike using your hips, thighs and legs is lower-body exercise and uses more energy at the same workload than cranking an upper body ergometer, because cycling uses more and larger muscles. Whole-body exercises, like rowing and cross-country skiing, are most demanding, because they combine upper and lower body. Finally, putting it all together, cross-country skiing is more demanding than rowing, because, while both are whole-body, skiing is weight-bearing.
This material is presented for educational purposes. It is not intended to diagnose or treat any condition. Neither is it a substitute for medical advice. Always consult with your physician. Once cleared medically, use the FITT Framework to increase your volume of cardio, beginning where you are now. Work toward your goals of losing weight, lowering blood pressure and cholesterol, holding off heart disease, or recovering from it. With a bit of effort and plenty of consistency, you’ll get there. As always, if I can be of help with this, or anything else, please contact me at the below.