We deeply appreciate the value of randomized controlled trials (RCTs) here at Healthcare Triage. When we come across a study that employs a series of RCTs to investigate the effects of exercise, it truly captivates our attention. This week, we have chosen to delve into this fascinating topic and explore its implications for healthcare.
Exercise is undoubtedly challenging, and finding time for it can be particularly difficult in our already hectic lives. According to a report published in The Lancet in 2018, around 27.5% of the global population lacks sufficient physical activity. This figure is even higher in high-income countries, and the United States is witnessing an increase in this trend. Shockingly, just over half of adults meet the guidelines for recommended aerobic activity, and only slightly more than 20% fulfill the requirements for both aerobic and strength exercises. However, exercise is undeniably beneficial for both physical and mental health. In fact, we have previously dedicated an entire episode to this topic, highlighting how exercise, apart from smoking, is among the few modifiable risk factors that have a profound impact on health. The evidence from RCTs on interventions aimed at increasing physical activity is substantial. Nevertheless, when attempting to compare the effectiveness of different interventions, the presence of various factors across separate trials can make the task challenging.
That's where the groundbreaking "mega-study" comes in. Recently published in Nature, this study marks the first known instance of combining multiple RCTs conducted simultaneously. The researchers undertook an extensive comparison of 53 four-week interventions against a control treatment, all designed to promote exercise. This massive effort involved over 60,000 members of 24 Hour Fitness, a prominent fitness chain in the United States. The study enlisted the collaboration of 30 scientists from 15 different universities. In the placebo group, participants received points for enrolling in the study, which they could later redeem on Amazon. Beyond this initial interaction, no further intervention was provided. Building on the understanding that exercise adherence could be improved with planning prompts, reminders, and modest cash rewards based on previous data, a baseline intervention was implemented with these elements. The remaining interventions were constructed upon this foundation.
Compared to the placebo group, 24 of the experimental conditions significantly increased the frequency of weekly gym visits. The baseline intervention, with planning prompts, reminders, and rewards, resulted in a nine percent overall increase in weekly gym visits. Furthermore, five of the experimental conditions went beyond the baseline intervention, yielding significant improvements in exercise participation. In two of these conditions, offering a small reward for returning to the gym after a missed workout led to a 12% and 16% increase in weekly workouts, respectively, compared to the baseline intervention. It is worth noting that the size of the rewards was genuinely modest, ranging from 9 to 16 cents, translated into points received by the participants. Interestingly, the study found that the 9-cent reward produced better outcomes than the 16-cent reward. In another condition, where participants were offered larger incentives (equivalent to about $1.75 per gym visit) compared to the baseline intervention, weekly gym visits increased by 14%. Additionally, informing participants that a majority of Americans engage in exercise, and that this number is on the rise, resulted in a 13% increase in gym visits compared to the baseline intervention. Lastly, in the fifth condition, allowing participants to decide whether they would earn points for going to the gym or lose points for skipping it, led to a nine percent increase in weekly gym visits compared to the baseline intervention.
Each condition in the study consisted of at least 455 participants, with a mean number exceeding 1,100 participants per group. The improvements achieved, as mentioned for each of the five conditions, translated into an extra 0 .28 to 0.4 weekly gym visits per participant. Considering that insufficient physical activity contributes to approximately 9% of premature deaths worldwide, even these modest improvements hold immense significance.
The design of this study is truly exciting, although it is likely to have presented logistical and financial challenges. Nonetheless, it allows for a more accurate comparison of interventions, as the researchers aptly put it, "comparing apples to apples." Such an approach could greatly facilitate the development of evidence-based health policies, eliminating the need to sift through piles of disparate findings.
We hope you found this article informative and engaging.
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