Closing gyms and leisure facilities during any possible future lockdown would be "unthinkable", according to Catherine McKinnell, MP for Newcastle upon Tyne North.

McKinnell – in her role as chair of the petitions committee – was speaking at today's (23 November) Parliamentary debate on gyms and sport, which was called following a Parliamentary petition that attracted more than 614,000 signatures.

During 90-minute debate, a number of MPs made statements, put questions and gave evidence to sports minister Nigel Huddleston, who stubbornly refused to confirm that gyms would stay open during potential future lockdowns – despite evidence suggesting that they are safe, controlled spaces.

The debate took place at the same time as the government announced – in the main chamber of the house just metres away – that gyms, health clubs and leisure centres will be able to open their doors when the current lockdown measures in England come to an end on 2 December, to the great relief of the sector.

However, MPs were intent on making the case for gyms and on securing some guarantees that gyms and sports facilities' futures would be secure.

McKinnell said: "It is hugely concerning that we aren't getting any certainty from the government that the re-opening of gyms will be long-lasting.

"I appreciate that none of us can predict this virus and the outcome of how things will go, but one of the lessons we've learned is that for people to stay fit, active and healthy is absolutely fundamental.

"It's not a 'nice to have'. It's not just a leisure activity, it's a fundamental part of people's health, their mental wellbeing and their ability to stay resilient and resistant to this virus," she said.

"I had hoped to hear much more clarity from the minister that any of the relaxing of restrictions that is being announced today (23 November) will not mean that in January, potentially, the facilities will have to close again.

"It's unthinkable, to be perfectly honest," she said.

"The average weight gain among my constituents during the first lockdown was 18lbs," said McKinnell. "People are motivated to join the gym in January and it would be catastrophic if gyms are shut then – many of them will have to close their doors permanently."

MPs that spoke in support of gyms staying open during future lockdowns included Jane Hunt, who said gyms and sports facilities must "start from a basic presumption of being open", and Nick Smith, who argued that sport and physical activity "has to be a fundamental part of the recovery and not an afterthought".

Perhaps the most significant revelation, however, was made by Conservative MP and former business secretary Greg Clark.

Clark suggested that the government's original decision to close gyms wasn't based on specific advice from leading scientists.

"Sport will be coming back and that is a very welcome development, but it still begs the question as to why it was cancelled in the first place," he said.

"The one thing we know about sport and exercise is that there is scarcely anything better in terms of a defence against COVID-19, whether that is practiced by older people or children, so having a comprehensive ban on an activity that helps guard against COVID-19 is a mystery.

"The fact that for the last month, activity has been suppressed for no good reason is something we need to learn the lessons of and prevent happening in the future," said Clark.

"On the Government's Science and Technology Committee that I chair," he said, "We know that Professor Whitty and Sir Patrick Vallance both commented on the low risk of infection from outdoor sport and its very low impact on the R rate.

"One of the things they said that concerned me is that their advice [to the government on COVID-19 measures] was given at a general level – a strategic level – and they didn't give specific advice on activities like sport [or gyms].

"That concerns me because there is evidence from the participation in this debate that this is something that is of great importance to our constituents.

"I respect the expertise of our leading scientists, but we need to have the ability to influence these decisions and scrutinise the evidence that's being used to cause lockdowns and not just have to accept a fait accompli," said Clark.

"I hope the minister will take from this debate that in future it will be possible to share with ministers the evidence on which decisions are made," he concluded.

Angela Eagle used her time on the floor to champion the transformative effect of the fitness sector.

"There's another consideration when dealing of health conditions which are helped by going to the gym," Eagle told Huddleston.

"I'd like to mention Thea Holden, a constituent of mine who suffers from Ehlers-Danlos syndrome, which results in multiple joint dislocations.

"She was confined to a wheelchair and on was on medication, prior to discovering that the disease could be managed by gym-going.

"She is now wheelchair free and drug-free as a result of the work she did – and runs her own gym – EmpoweredFit," said Eagle.

Huddleston seemed largely unmoved by the passionate representation, reading out a prepared statement in which he confirmed that no sector-by-sector analysis had been done to determine government strategy during lockdowns and that the general opinion of the government was that "We all needed to sacrifice doing the thing we would like to do for a short period of time", regardless of whether they were safe.

In response to the MPs tide of questions regarding a range of types of physical activity, including swimming, gyms, golf, tennis, parkrun and football, Huddleston said: "There have been calls for exemptions to restrictions, with some giving plausible reasons, but we have heard this from gyms, swimming, tennis, golf etc etc," effectively indicating that too many people had given good reasons.

"This long list exemplifies why we've had problems, because when you unpick one thing the whole wall falls down," he said, effectively indicating that the government would rather close everything, regardless of whether there is any evidence for doing so, rather than be more forensic.

Huddleston acknowledged the problems brought about by the closures, saying: "We know that closing these gyms and sports facilities has damaged people's health, but it has saved lives and that has made it worth it."

HCM editor, Liz Terry said: "It was very moving to see so many MPs coming out to represent the gym, sports and physical activity sector – especially on the day we found out that gyms can reopen in December.

"However, in the face of such genuine and heartfelt passion from MPs and their real-world evidence of the impact exercise has on people's lives, it was painful to watch Nigel Huddleston floundering around and refusing to answer logical questions about why the physical activity sector has been locked down.

"He could not satisfactorily answer the challenges and fell back on reading out a government statement.

"I hope this matter will be pursued, as Giles Clark raised a very important point about accountability and the advice given by SAGE scientists that needs to be answered.

"If the government tries to lock the gyms sector down again, I don't believe operators will be so obliging as they have been during these firsts two lockdowns," said Terry. "We expect legal action would be taken and for a large group of operators from across the sector to pursue the government for millions of pounds of damages."

• The parliamentary debate is viewable in its entirety on Parliament Live TV – click here to access the website.