An effective approach to gradually increase fitness intensity involves utilizing the principle of progression. This entails systematically increasing the duration, frequency, or difficulty of workouts over time. For instance, one might start by increasing weights, adding repetitions, or decreasing rest periods as fitness improves. Setting specific, measurable goals helps maintain focus and motivation. It's crucial to listen to the body, allowing adequate recovery to avoid injuries. This method ensures sustainable improvements and encourages continuous growth in fitness levels.