Will NHS England’s ‘Marathon a Month’ Challenge make us healthier?

“Similar schemes to this have been tried around the world with varying results, so there is already quite a lot of evidence available on the impact this could have.

“For instance, Singapore's National Steps Challenge increased activity by around 1,400 steps per day during the challenge period, while Canada's Carrot Rewards only managed about 116 additional steps per day. Vitality's data shows much larger gains among previously inactive participants than among people who were already active.

“So, there is evidence these schemes can work for some people.

“A lot of the discussion when we talk about these types of schemes is focused on whether vouchers will motivate people. The more important question is potentially being missed though: is it just lack of motivation that stops people from exercising enough?  

“Many of the least active groups in our society face structural barriers; disability, caring responsibilities, unsafe streets, long working hours, poor transport links, etc.

“If these are the real issues stopping someone from exercising, then simply offering rewards for higher step counts will have limited impact.

“We also don’t really know from similar schemes, whether people keep walking once the rewards stop. Some may find ways of gaming the system or get rewarded for behaviour they were doing anyway. We could even end up encouraging people to become dependent on rewards.

“A recent study at the University of Salford has found that people can get into ‘unhealthy relationships’ with fitness trackers, becoming overly reliant on them and reluctant to exercise unless they are wearing their tracker and getting the positive reinforcement it brings.

“The real test is not whether step counts rise for a few months; it is whether health outcomes improve in a sustained way.”