Don't Bank on Borough Size: The Flaw in Assuming Population Guarantees Fitness Rates in London
Something counter-intuitive is happening in London's health data.
The conventional wisdom that guides public understanding of physical activity in London is built on two deceptively simple assumptions:
The more money a borough has, the more active its residents will be.
The sheer size of a borough's population should guarantee a higher overall percentage of active people.
Yet, when we examine the most recent, rigorously verified data from Sport England’s Active Lives Survey, a critical disconnect emerges. The boroughs with the highest proportion of adults meeting the Chief Medical Officers’ minimum physical activity guidelines are neither the largest nor the greenest peripheries of Outer London, as commonly presumed, but the dense, central urban cores.
I will argue why the simple 'wealth equals activity' model and the associated 'scale equals activity' model both fail to explain this paradox, and that the true driver of high activity levels is the systemic necessity imposed by urban density and walkability. Resolving this problem is critical because it reveals a profound lesson about incentives in public health. My argument is that the London boroughs topping the activity league tables are those whose dense, inner-city infrastructure implicitly compels active travel, providing a non-optional, daily foundation of movement that reliably surpasses the voluntary exercise choices made in more car-dependent suburbs, irrespective of the borough's total population count.
Defining the Terms: Active vs. Leisure-Active
Before addressing the argument, we must clarify what 'active' truly means in this context. According to the Chief Medical Officers’ guidelines, an adult is classified as Active if they accumulate at least 150 minutes of moderate-intensity equivalent physical activity per week. Crucially, this definition makes no distinction between planned exercise (such as a gym session or a game of football, what we call Leisure Time Physical Activity or LTPA) and activity integrated into daily life (such as walking to work or cycling to the shops, what we call Active Travel). The common assumption, which confuses LTPA with the total activity score, is where the error lies.
The Problem of Assumptions: Inner London’s Systemic Advantage
The core of the issue is that both general wealth and population size, as predictors of activity rates, are flawed assumptions. While affluence correlates strongly with the option to be active (e.g., affording gym memberships), and a large population offers a high count of individuals, the data shows that urban geography correlates with the necessity to be active, which dictates the percentage.
The official data for November 2023–24 is compelling. The most active boroughs in London are not places like Havering (52.9% active) or Bexley (54.6% active). Nor are they the very largest boroughs by population, such as Croydon (with a high resident count but a mid-tier activity rate). Instead, the top performers are Camden (77.4% active) and Islington (75.7% active). While Richmond upon Thames (75.4%) and Kingston upon Thames (74.1%), traditionally wealthy areas, do rank highly, they are flanked by inner-city boroughs like Lambeth (74.8%) and Hammersmith and Fulham (74.5%).
The pragmatic argument here is that the higher density and inner location of areas like Camden and Islington inherently reduce the practicality and desirability of car travel. For a resident in these areas, the first step out of the door, a walk to the Underground or a cycle to a central workplace, is frequently an act of Active Travel that immediately contributes towards their 150-minute goal. This daily, compelled movement provides a systemic, resilient baseline of physical activity that is simply unavailable to residents in more sprawling, car-reliant suburban settings, regardless of their household income or the total number of people living there.
Dissociating Wealth and Scale from Mobility: The Power of Structural Compulsion
I think we must dissociate Affluence and Population Scale from the actual engine of high activity rates: Structural Compulsion. This distinction is critical, as it moves the explanation away from simple resources and toward environmental design.
Affluent Outer London boroughs possess the wealth to facilitate high Leisure Time Physical Activity (LTPA). A resident of Havering may have the income to join two gyms and own premium cycling equipment. However, the sprawling, car-centric design of that borough, its wide roads, distant amenities, and reliance on suburban infrastructure, creates an environmental condition where the fastest, most convenient option for the majority of journeys is inevitably the car. This structure acts as a powerful Structural Deterrent against incidental movement. The result is that a high population count (e.g., Croydon) or a high median income (e.g., Havering) cannot compensate for this daily, systemic inactivity.
In sharp contrast, Inner London boroughs benefit from a powerful Structural Compulsion towards movement. In areas like Camden (77.4% active) and Islington (75.7% active), dense urban planning means that the friction and time cost associated with using a car (congestion, parking scarcity, traffic restrictions) is often greater than the friction associated with walking or cycling. The environment actively 'nudges' residents into active travel. The high rates of Active Travel accumulated by residents merely by conducting their daily routines, the walk to the tube, the cycle to a business district, provide a non-optional baseline of minutes that the Outer London suburbs structurally fail to generate.
Therefore, the superior performance of the central boroughs is not due to greater moral virtue or proportional scale; it is because their highly dense infrastructure successfully layers high rates of compelled Active Travel onto high rates of voluntary LTPA. The underperforming Outer London boroughs, despite their resources, lack this critical Active Travel layer, revealing a significant drop-off in total activity minutes, a direct failure of their urban structure, not their residents' effort.
Addressing the Leisure Facility Counter-Argument
A counter-argument is that areas like Havering and Bexley are struggling not because of transport, but because they have fewer high-quality leisure facilities than central boroughs, or that their populations are simply older. This suggests a false premise: that facility provision is the primary issue.
While facility quality and demographic distribution are certainly relevant factors, they do not invalidate the primary argument about urban necessity. If the problem were solely facility provision, we would expect activity rates in Outer London to still be significantly higher than the least affluent parts of the capital, given the resources available for voluntary activities. However, the data shows Outer London boroughs like Havering performing worse than the London average (64.6%) by nearly 12 percentage points, ranking them alongside some of the capital's most deprived areas. The fact that the most resource-rich suburbs are still lagging so far behind the inner core proves that systemic mobility structure is the missing explanatory variable. Facility availability helps LTPA, but it cannot compensate for a lack of daily, fundamental movement.
Defending the Argument Against Demographic and Scale Criticism
The strongest refutation of my claim would argue that I have committed a logical fallacy by generalising from borough-level data, or that the demographic composition of Inner London (younger, fitter commuters) is the true cause, not the environment. A critic might argue that the lower total population of the highest-ranking boroughs makes the high percentage an unreliable, volatile measure.
I think that the observed effect remains valid regardless of internal variation or size volatility. The Inner London boroughs that attract and retain a younger, active demographic do so precisely because their dense urban structure, with its concentration of jobs, leisure, and highly efficient non-car transport, is inherently appealing to, and supportive of, an active lifestyle. The environment selects the active resident. Furthermore, the goal of public health is to ensure the highest possible proportion of the entire population meets the minimum health guidelines, not simply to have a high total count. My argument is that the urban structure itself acts as a powerful lever for activity, providing a systemic advantage that car-dependent suburbs simply cannot match, regardless of their wealth or the initial demographic mix.
