handed over her credit card; you’d congratulate her on the purchase and
wish her a nice day. Well, the same principles apply to exercise. No matter
what type of cardio workout you do — whether it’s walking, playing basket-
ball, or cross-country skiing — you need to ease into it with a warm-up and
ease out of it with a cooldown. (Weight-training workouts also require a
warm-up, as we explain in Chapter 14, although they typically don’t require
a cardio cooldown.)Warming up ........................................................................................
A warm-upsimply means 5 to 15 minutes of aerobic exercise at a very easy
pace. For example, runners may start out with a brisk walk or a slow run. If
you’re going on a hilly bike ride, start with at least a few miles on flat terrain.
Be aware that stretching is not a good warm-up activity (see Chapter 6).Part III: Getting to the Heart of the Matter ................
What does aerobicmean, anyway?
The term cardiois often used interchangeably
with aerobic.Aerobic exercise is any repetitive
activity that you do long enough and hard
enough to challenge your heart and lungs. To
get this effect, you generally need to use your
large muscles, including your butt, legs, back,
and chest. Brisk walking, bicycling, swimming,
and stair climbing count as aerobic exercise.
Movements that use your smaller muscles,
like those leading into your wrists and hands,
don’t cut it. Channel surfing with your remote
control can certainly be repetitive, sustained,
and intense — particularly when performed by
certain husbands and boyfriends we know —
but it’s not aerobic.
Aerobicmeans with air, and cardiowas coined
in the late 1960s by fitness pioneer Dr. Kenneth
Cooper, and it means heart. When you exercise
aerobically, your body needs an extra supply of
oxygen, which your lungs extract from the air.
Think of oxygen as the gas in your car: When
you’re idling at a stoplight, you don’t need as
much fuel as when you’re zooming across
Montana on Interstate 90. During your aerobic
workouts, your body continuously delivers
oxygen to your muscles.However, if you push yourself hard enough,
eventually you switch gears into using less
oxygen: Your lungs can no longer suck in
enough oxygen to keep up with your muscles’
demand for it. But you won’t collapse, at least
right away. Instead, you begin to rely on your
body’s limited capacity to keep going without
oxygen. During this time, you’re exercising
anaerobically,or without air.
Anaerobic exercise refers to high-intensity
exercise like all-out sprinting or very heavy
weight lifting. After about 90 seconds, you begin
gasping for air and you feel a burning sensation
in your legs. That’s when your body forces you
to stop.