Cycling as a Part of Daily Life

New Health aspects of day-to-day cycling have gained attention from the health sector aiming to increase levels of physical activity, and from the transport and planning sector, to justify investments in cycling. We review and discuss the main pathways between cycling and health under two perspectives — generalizable epidemiological evidence for health effects and specific impact modeling to quantify health impacts in concrete settings. Substantial benefits from physical activity dominate the public health impacts of cycling. Epidemiological evidence is strong and impact modeling is well advanced. Injuries amount to a smaller impact on the population level, but affect crash victims disproportionately and perceived risks deter potential cyclists. Basic data on crash risks are available, but evidence on determinants of risks is limited and impact models are highly dependent on local factors. Risks from air pollution can be assumed to be small, with limited evidence for cycling-specific mechanisms. Based on a large body of evidence, planners, health professionals, and decision-makers can rest assured that benefits from cycling-related physical activity are worth pursuing. Safety improvements should be part of the efforts to promote cycling, both to minimize negative impacts and to lower barriers to cycling for potential riders.

Introduction

Cycling as a means for day-to-day travel has gained attention from the transport and environmental sectors for a number of advantages over motorized travel. More recently, the health sector has begun to embrace cycling for its potential to increase physical activity levels in children, adults, and older adults.

Regular physical activity provides a wide range of health benefits. The World Health Organization recommends a minimum of 150 minutes of moderate physical activity per week. But despite substantial benefits, increasing proportions of western and other populations fail to achieve recommended levels of activity. Integrating cycling into daily routines provides a promising approach to increase physical activity, given the many people who spend 30 minutes and more commuting daily, yet struggle to find the extra half-hour to exercise. The combination of mobility and physical activity is also cheap and does not require major skills, making it suitable for large segments of the population.

Nonetheless, cycling has remained a marginal factor in both transport and health policies, with only few exceptions. Reasons for this may in part be the perceived risks of crashes and exposure to air pollution associated with (urban) cycling, the generally small mode share of cycling (with few exceptions), various socio-psychological and environmental barriers, or a simple lack of prioritization in policy and planning, among others. One may argue that understanding the implications of cycling for (public) health is an important foundation for policy, planning, and decision-making related to cycling, and equally so for the individual decision to cycle.

This narrative review aims to highlight issues and key findings of relevance for a better understanding of health aspects of day-to-day cycling. The focus is on types and purposes of cycling that are the targets of cycling promotion in the general population, such as approaches to sustainable transport, livable communities, or physical activity promotion. This includes cycling for recreation, in the sense of leisurely or moderate-to-vigorous rides with the primary purpose of recreation, fitness, or health, but explicitly excludes cycling for sports or competitive cycling, although various health aspects apply to it equally.

Health effects of cycling can be both positive (benefits) and negative (risks). The main pathway for health benefits from cycling is physical activity. Other beneficial pathways include improvements of quality of life through mobility and access gained through cycling. Some beneficial outcomes, such as improved cognitive function or reduced risk of depression, may reflect a mix of all these pathways. Finally, there are indirect health benefits of reduced motor vehicle use when cycling trips replace car trips (e.g. reduced air and noise pollution, and increased social engagement in more livable communities).

The main negative pathways are crash risks and the risk of increased exposure to air pollution while riding in motorized traffic.

This review scopes out key publications around these main pathways to present a structured overview, methodological insights, and selected key issues we consider important to understand the links between cycling and health. Health benefits and risks of cycling are complex, context dependent, and often under-researched. Consequently, it is not always possible to come to definitive conclusions. The review of the literature is not systematic or comprehensive, but numerous references to original research as well as systematic reviews are provided to facilitate more in-depth inquiries on specific aspects. Two main perspectives are explored.

The first perspective focuses on epidemiological evidence of effects of cycling on the most relevant health outcomes. These studies describe the relationships between clearly defined exposures (cycling) and outcomes (health endpoints), such as the magnitude and shape of the association that can be expected to be generalizable to other populations. This evidence is useful to determine whether cycling is ‘healthy' or ‘risky', but it is not sufficient on its own to inform public policy on the value of promoting cycling at the population level.

The second perspective focuses on health impact modeling to quantify the magnitude of impacts, such as the prevention of diseases, by specific policies or scenarios in realistic settings, namely in clearly defined populations and over defined periods of time. Epidemiological evidence is at the core of health impact modeling, but in addition health impact models apply their own set of methods. New.