Firstly, I would like to point out an aspect of exercise that I think helps with creating more flow. It is breath awareness and body awareness. Normally, humans are conditioned to keep their attention mainly in their forehead region in their thoughts. For women, their emotions may also draw more of their attention. (Women feel emotions more strongly than men). For men, sexuality can sometimes be more stronger. So.. during exercise, for example running, we can find our attention more in our breath. Or in martial arts for example, we can be more aware of our bodies. This action of focusing more on the body or the breath withdraws attention from the thoughts in the forehead region. Energy flows where attention is placed, so thoughts are less empowered. This will result in a more peaceful mind after exercise.
Breath awareness is very significant because breath is a focal point used in meditations coming from ancient times. It is linked with our energy system going to the deepest levels. I am not a master of this, but I have many years of experience with meditation. Focusing on the breath effectively calms the mind and with a calm mind you can access your inner knowing better.
Also movement of the body with awareness will energize the body. Energy will travel more throughout the areas of the body we are more aware of than our regular state because energy flows where attention is placed. In general the system will be more energized. If the system has no broken parts, or has the capacity to hold this additional energy, then the overall health will be improved. If for example, you are bleeding from a wound and you exercise, then you can harm yourself. Your body is like a container of energy. The more healthier the container is the more energy it can store. And the health is determined by your mental/emotional/physical bodies and actions. The mental level can go very deep, to your very spirit, to your spiritual heart. If you lessen the container by eating say.. less healthy food, then the body’s capacity of holding the energy will also lessen.
The more awareness you have of all aspects of yourself, the more your capabilities as a creative being will be realized. The core way to uncover our creativity is connecting with our deepest aspects. The following articles/videos touch the topics of breath awareness and spiritual heart awareness. You can start with breath awareness/body awareness with your exercises and proceed to deeper levels. The videos are given as a reference, should you wish to explore this answer in detail at any time. You can learn how breath or heart awareness works and what awareness is and how can one stay as awareness from these resources.
I personally ‘work’ to stay connected to my spiritual heart and live as awareness. These I have learned through the meditations and teachings similar to those above. I have studied these a lot, and can see the connections with exercise. I am also an ex international competitor in Japanese martial art Kendo. I have decades of exercise experience. For creativity to blossom, in the path I pointed to, we must keep trusting to our innate intelligence and with its guidance that is one with us, naturally and effortlessly evolve our understanding, gradually letting go of our resistances.