Exercise referral schemes are associated with many improvements in health and wellbeing, but the changes aren't as large as hoped, finds an analysis of outcomes data published online in the Journal of Epidemiology & Community Health.UK roll-out of these schemes needs to be rethought to maximise their effectiveness, conclude the researchers.

Physical activity is associated with the maintenance of good physical and mental health and with staving off serious illness and long term conditions.

But a recent survey shows that a large proportion of the UK population isn't doing enough exercise, with the associated costs to the NHS reaching £1.2 billion in 2017 alone, say the researchers.

Exercise referral schemes were first introduced in primary care in England in the 1990s to boost physical activity levels among those with, or at risk of, long term conditions.

Usually a family doctor (GP) makes the referral to a programme lasting up to 16 weeks that often includes both cardio exercises and resistance training at a sports or leisure centre.

Most of the studies evaluating these schemes to date have focused primarily on whether they increase physical activity levels, rather than improvements in health and wellbeing as well, say the researchers.

To try and address this, they drew on data from 23,731 active participants in 13 different schemes, lasting between 6 weeks and 3 months, which had been entered into the dedicated UK-wide National Referral Database.

They looked at measurements recorded at the beginning and end of the schemes in: weight (BMI); blood pressure; resting heart rate; and scores on internationally validated mental health, wellbeing, quality of life and exercise confidence scales.

Analysis of the recorded changes revealed significant improvements in most of the included measures, the exceptions being resting heart rate, which is a known risk factor for death from cardiovascular disease; and diastolic blood pressure (the bottom number in a blood pressure reading, signifying the pressure in the arteries between heartbeats).

But when these figures were compared with thresholds for clinical "meaningfulness," the changes didn't reach these thresholds. In other words, the size of the changes was small, rendering their impact unclear.

This is an observational study, and as such, can't establish cause. And there were considerable differences in outcomes between individual schemes, the researchers point out.

What's more, the schemes varied considerably in length and content, as did the characteristics of the participants, so it's not clear which combination of activities and length of scheme might be most effective, or for whom.

"As noted, currently there is a lack of agreement of what constitutes 'impact' with respect to the evaluation of [exercise referral schemes] and the evidence presented here from one of the largest databases of [them] does little to support the use of [them], broadly speaking," they write.

Given how widely used these schemes are, a more critical approach is needed, they suggest.

"These findings support the need to consider exercise referral schemes, particularly their implementation, more critically, using real world data to understand how best to maximise their potential, particularly considering the known benefits of exercise and the research of [exercise referral schemes] across the UK," they conclude.