Light = Energy
Poorly lit home gyms tend to lack energy whereas a bright space with a generous amount of light is generally more inviting for exercise and can be crucial to creating just the right environment for a vigorous or energetic workout.
Natural Light is Best
Natural light coming from plenty of windows and skylights is the best source of light for a home gym. If the natural light in your home gym is only minimal or non-existent, try using good fluorescent lighting that emulates sunlight. This means that the fluorescent light bulbs should have a high color temperature of 5000K-5500K and very good color rendering of 82 or higher.
An Even Distribution of Light Helps
Besides supplying a good substitute for natural lighting, good fluorescent lighting can also provide a good even distribution of light throughout your home gym. An adequate number of well-positioned fluorescent light fixtures can minimize any dramatic "hot spots" of light or bright "point sources" of light. This, in turn, can help you focus on your exercising routine and not be distracted by the lighting.
Avoid Direct Glare
If part of your exercising routine calls for you to lie on your back and look upward at the ceiling, then you may especially want to avoid using halogen recessed downlights since they could provide a good deal of annoying glare directly into your eyes.
Try Dimmers & Dual Switching
For certain activities that require a lower energy level in your home gym such as yoga, cool down periods, sauna sessions, whirlpool baths, or massages you should consider lowering the light levels. Dimmers can assist you in controlling the brightness of the lights in your home gym. If you have fluorescent lighting that do not have special dimming ballasts and special fluorescent dimmers, you may want to wire them so that some of the fluorescent fixtures are controlled by one on/off switch and the remainder of the fixtures are controlled by a second on/off switch. This is called "dual switching" and it is a relatively easy way to simulate, to some degree, the dimming process with fluorescent lighting.