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(Hypertension. 2005;45:e1.)
© 2005 American Heart Association, Inc.

Hypertension Electronic Pages

Comparing the Roles of Physical Activity and Fitness in Arterial Stiffness: How Important Is Exposure Measurement Error?

Diabetes Epidemiology &Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

The article by Boreham et al¹ in the November 2004 issue of Hypertension reports the associations between physical activity and cardiorespiratory fitness with pulse-wave velocity (PWV), a measure of arterial stiffness. One of the objectives of the study was to compare the relative relationships of physical activity and fitness with the outcome PWV. Indeed, the authors’ interpretation of their data leads them to state that "arterial stiffness related benefits of exercise are most likely to accrue if exercise prescription in young adults targets improvements in cardiorespiratory fitness", implying that fitness is more important than physical activity in preventing stiffening of the arteries.

Clearly, understanding the manner in which modifiable factors such as low physical activity and poor fitness relate with cardiovascular health is important for disease prevention. However, the conclusions and recommendations in the present study are based on data in which differential exposure measurement error is probably a pivotal factor; this possibility receives little attention in the article.

Cardiorespiratory fitness, as assessed through a maximal oxygen consumption test, is not a simple construct, because fitness is determined by both modifiable factors, such as habitual physical activity (volume, intensity, and mode), smoking, and cardiovascular pathology, as well as nonmodifiable factors, such as genotype and intrauterine environment. Therefore, in considering the risk predisposed by low fitness and physical inactivity, one should preferably measure both exposures to a similar level of precision and then assess them in combination, thereby accounting for any shared variance. However, this is difficult to . . . [Full Text of this Article]

Colin A. Boreham

School of Applied Medical Sciences and Sports Studies, University of Ulster, Jordanstown, Northern Ireland

Isabel Ferreira

Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands, and Department of Public Health, Erasmus MC—University Medical Center, Rotterdam, The Netherlands

Jos W. Twisk

Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands

Alison M. Gallagher

Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Jordanstown, Northern Ireland

Maurice J. Savage

Department of Child Health, The Queen’s University of Belfast, Belfast, Northern Ireland

Liam J. Murray

Department of Epidemiology and Community Health, The Queen’s University of Belfast, Belfast, Northern Ireland

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