Energy is something that is part of us all the time - we're living beings that are constantly in motion. Some activities tend to increase our energy levels a lot more than others. This may be because of the natural high that we experience when we produce endorphins, or it may because during certain activities we are able to focus and "get into a zone", so to speak, that allows us to consciously generate energy and power.
In some spiritual traditions, sacred sex is considered a perfect opportunity to raise energy for magic. The energy builds and builds, and at the moment of orgasm, all the energy is released into a particular focused intent.
Other people find that vigorous exercise has the same effect. In fact, if you work out regularly, you know that once you're trotting along at a rapid clip on the treadmill, or lifting weights, doing yoga, or putting your body through other repetitive activities, you may find yourself almost in a trance-like state. This is a time in which you can gather and focus energy, store it for later. If you're capable of letting your mind explore while your body works, you can have all kinds of interesting experiences -- including encounters with deities.
While what you've experienced probably isn't one that everyone has had, it's certainly not unheard of. When I exercise, I tend to separate my brain from my body, and my mind seems to go on walkabout while the rest of me chugs along on the elliptical machine. I've also found that incorporating music into my routine allows me to tune out exterior noises (like the idiot next to me yapping on his Bluetooth) and it enhances the meditative experience.
Drummers and dancers often experience this as well. Participate in a Spiral Dance some time, and feel the energy coming off people in waves. Or sit in on a drum circle if you get an opportunity -- by the time everyone is done, your body will practically be humming with the excess energy -- and many people report encounters with the Divine as part of this.
So yes, absolutely -- you can use exercise to raise spiritual energy as well as physical. The trick is -- and if you're working out regularly you probably have this figured out already -- to train your body to store that energy so that you can feel good all day long, rather than allowing yourself to become exhausted. And, if you're lucky enough to have a spiritual encounter while you're at it, appreciate the gift!