Just How Does Exercise Boost Energy? continued...
While some of that energy comes from your diet (one reason that eating too little can power down your metabolism), the number of mitochondria you have -- and thus your ability to produce energy -- is affected by your daily activity.
"For example, the more you exercise aerobically, the more mitochondria the body makes to produce more energy to meet your needs, which is one reason how -- and why -- regular cardiovascular exercise actually creates more available energy for your body," says Heller.
Exercise for Energy: What Really Works
So just how do you go about getting some of this energy for yourself?
First of all, Thayer says, it's important to understand that there are different types of energy. And not all have the same positive effect on the body.
He says that many Americans, particularly "achievement-oriented Type A people" have "tense energy" -- an effective state that allows you to get lots of work done, but that can quickly move into tense-tiredness, a negative state often associated with depression.
On the other hand, what he calls "calm energy" is a combination of a high physical and mental energy level, paired with low physical tension. It is this state, he says, that offers more long-lasting energy. And, he says, it can be achieved with the right kind of exercise.
"What summarizes the relationship best is moderate exercise -- like a 10- or 15-minute walk -- has the primary effect of increased energy, while very intense exercise -- like working out at the gym, 45 minutes of treadmill -- has the primary effect of at least temporarily reducing energy, because you come away tired," he says.
Behavioral therapist and personal trainer Therese Pasqualoni, PhD, agrees.
When exercising for energy, she says, "You should always aim to exercise in your low to moderate training heart rate range. This will prevent you from depleting your body, and help you avoid feeling fatigued, which would otherwise prevent you from getting the maximum energy benefits."
Of course, what's moderate for some may be too little for others. "How much you can do before you cross the threshold into tiredness is often dependent upon how well your body is conditioned," Thayer says.