Low cardiorespiratory fitness could be a harbinger of future problems, even fit and healthy – ScienceDaily

Cardiorespiratory fitness refers to the ability of the bloodstream and respiratory systems to provide enough oxygen to the muscles during sustained physical activity. The main measure used is VO2max – the maximum rate of oxygen consumption during exercise that increases with intensity.

In the study published today, the cardiorespiratory health of 4527 men and women in good and healthy form, without a history of cardiovascular or pulmonary disease, cancer or high blood pressure, was badessed when they joined a large population-based health study in Norway (HUNT3 study). ) between 2006-2008. Wearing a face mask and a heart rate monitor, they warmed up for ten minutes on a treadmill before running faster and faster. Their oxygen supply was measured to establish their VO2 max. The researchers also collected information on smoking, alcohol consumption, family history of cardiovascular disease, physical activity, weight, height and waist circumference, blood pressure and blood pressure. cholesterol.

After an average follow-up period of almost nine years, the researchers found that better cardiorespiratory fitness was linked to a lower risk of cardiovascular disease, such as heart attacks. During this period, only 147 participants (3.3%) were diagnosed or died of heart disease, or required intervention to unblock clogged arteries.

"We found a close connection between better fitness and reduced risk of coronary events over the nine years of follow-up in a very healthy sample of adults," said Dr. Bjarne Nes, a researcher at the Norwegian University of Science and Technology (NTNU). ). "In fact, participants who were among the 25% of those with the highest cardiorespiratory fitness were nearly half the risk, compared to the 25% with the lowest fitness levels."

The researchers found that for both men and women, the risk of cardiovascular problems decreased by 15% for each additional unit of measurement of cardiorespiratory fitness – metabolic equivalents (METs). METs measure the oxygen needed for the energy expended for physical activity, a MET being the amount needed if a person is sitting quietly (3.5 mL of oxygen per kg of body weight). per minute), while an intense effort, like running, consumes around eight hours. METs.

"This indicates that better cardiorespiratory fitness protects against chronic and acute problems of the heart and blood vessels," said Dr. Nes. "Even a small increase in fitness could have a big impact on health."

The lead author of the study, Dr. Jon Magne Letnes, a physician and researcher at the Heart Exercise Research Group at NTNU, said: "Our findings should encourage Use of exercise as preventive medicine A few months of regular exercise can be an effective way of reducing cardiovascular risk.

One of the strengths of the study was that cardiorespiratory fitness was measured using a maximal exercise standard exercise test for maximum oxygen uptake (VO2peak) – the first to do it on a healthy sample of the general population. Previous studies that linked physical fitness to disease risk in healthy populations rely primarily on self-reported or less accurate estimates.

One limitation of the study is that participation in voluntary exercise tests introduces the possibility that more active individuals may choose to participate in the study, which may reduce its applicability to the general population.

In an accompanying editorial, Professor Sanjay Sharma, of St George's University of London (UK), medical director of the London Marathon and chairman of the group of experts in English Football Association's cardiology, and Dr. Aneil Malhotra, also of St George's, write: "This study adds to current literature by demonstrating a similar benefit in an apparently healthy population with a additional benefit that stays above 12 METS and suggests that there is no obvious upper threshold for the cardioprotective effects of exercise.Although the number of subjects is laudable, it There are several points to note. "

They point out that there is an unavoidable but inherent selection bias for participants who were motivated to participate and who were probably more aware of lifestyle measures to avoid cardiovascular disease; and the participants were young and healthy, which explains the low number of events related to cardiovascualar during the follow-up period.

They conclude: "At a time when primary prevention is playing an increasingly important role in society, this study highlights that the improvement of the CRF [cardiorespiratory fitness] is a critical factor in reducing the CV [cardiovascular] risk and mortality. Regular physical activity and CRF measures need to be incorporated into the clinical practice and cardiovascular risk models. All individuals should be encouraged to exercise at the minimal level recommended by the European Directives for the prevention of disease, although the observations of Letnes and colleagues and others suggest that levels of blood pressure should be low. Physical activity and significantly higher CRFs offer additional prognostic benefits. For those who are compromised because of comorbidities or their functional status, there is ample evidence that some physical activities are better than nothing. "