Yes. Sport England produced design guidelines for gyms in 2008 and this document talks about a noise rating of NR40 being the appropriate maximum for most gym spaces. NR 40 has to be calculated using sound pressure measuring equipment that can take measurements across a range of the audible frequency range. These are guidelines, not mandated, however the management of the gym should be interested in ensuring an understanding of this as they have a duty of care to their employees.