Almost half (46 per cent) of the new gyms that opened in Central London last year were budget gyms, classed as having membership plans costing less than £50 a month.
Budget gym groups such as Pure Gym, which abandoned plans for a £190m IPO in October, and Easygym have "exploded" onto the London fitness scene, according to global real estate adviser Colliers International.
The low-cost market has helped drive 21 per cent overall growth in the capital's gym sector, Colliers said.
"Once the preserve of regional towns and cities, budget gym operators have cast aside concerns of rent affordability in London and are catering to the large number of customers who are keen to swap expensive monthly memberships in favour of no frill concepts," said Ross Kirton, head of UK leisure agency at Colliers.
Although budget gyms don't break the bank for their customers, Colliers found budget operators are typically paying 19 per cent, or £2.50 per square foot, more for space than their mid-market competitors.
Colliers also found Central London could support an extra 30 gyms, equivalent to 26 per cent growth, based on the current worker-to-gym ratio.
Farringdon, Clerkenwell, Shoreditch, Aldgate and Victoria have been tipped as the five areas with the greatest potential to support new gym openings (perhaps Southern rail customers can bulk up at the gym while they wait for their trains).
Farringdon, where last year Gymbox opened its 42,000 sq ft flagship gym, has the potential to support at least 10 additional full gyms or 20 studios based on a current ratio of 56,000 workers per gym in 2016, Colliers found. This is compared with the optimum of 24,600 workers in an area per gym.