The phrase "a matter of exercising" is correct and usable in written English.
It can be used when discussing the importance or necessity of engaging in physical activity or practice.
Example: "For many, maintaining a healthy lifestyle is simply a matter of exercising regularly and eating well."
Alternatives: "a question of practicing" or "a case of working out".
"It can be done, it's just a matter of exercising the political will and political skill to make it a reality".
Among the many voices arguing the cartoon's publication is a matter of exercising the right to free speech was Boris Johnson, who suggested Charlie Hebdo had "no choice" but to print the cover following the unity marches in France and defences of press freedoms in the wake of the attacks.
It is not just a matter of exercising an institutional imagination within broadly understood democratic norms and ideals.
The government said it was aiming to deal with asylum requests within a matter of hours, exercising the right to reject them almost immediately on the grounds that Hungary — as of July — considers Serbia a 'safe' country for refugees.
If the account satisfactorily realizes this familiar conception, then it may be credibly claimed that the difference in question between worlds is a matter of Leo's exercising his free will differently.
It's a matter of making exercise a priority above the other things you have to do.
But the bottom line is almost always the same: losing weight and keeping it off is a matter of diet, exercise and discipline.
I argue that arriving at The Good is not a matter of opinion, but one of exercising sound judgment.
It seems to be a matter of comfort, having and exercising choice, and perhaps even a refusal on the part of many Indian women to be the repository of traditional fashion.
"If they do take that benefit away then it is a matter of removing the exercise equipment and staying in the house as much as possible to avoid any extra costs relating to my disability".
But the "can" here seems to be just a matter of chance: Elena actually exercises active control one way, and there remains, until she does, a chance that she will exercise such control a different way.
