MedicalResearch.com Interview with:
Jari Laukkanen MD, PhD
Institute of Public Health and Clinical Nutrition
University of Eastern Finland
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: In this population-based study we found a strong inverse association between long-term change in directly measured cardio-respiratory fitness (CRF), using maximal oxygen uptake (VO2peak) and all-cause mortality. A small decrease in CRF over 11-years was associated with a lower risk of all-cause death in a graded fashion. The observed association was independent of risk factors. This population-based study with repeated and direct assessment of CRF using a very similar time-interval for all participants, whereas some previous studies showing the value of CRF were constructed on participants referred to exercise testing at varying time-intervals between two repeated tests using only indirect cardio-respiratory fitness assessment or other exercise scores.
Cardiorespiratory fitness was assessed at baseline and follow-up using respiratory gas analyzer which is a golden standard for assessing aerobic fitness level. A single assessment of CRF predicts outcomes, however, no previous studies using directly measured VO2max have shown the association between long term changes in VO2max (i.e. 10 years) and its association with mortality. In the recent study VO2max defined from respirator gases with similar time-interval between two separate assessments of VO2max (=directly measured). This is a very novel finding in the field of exercise sciences, as well as in cardiovascular prevention and rehabilitation.
Although cardio-respiratory fitness is recognized as an important marker of functional ability and cardiovascular health, it is currently the major risk factor that is not routinely and regularly assessed in either the general or specialized clinical setting, although it is suggested that an individual’s CRF level has been even a stronger or similar predictor of mortality than the traditional risk factors, including smoking, hypertension, high cholesterol, and type 2 diabetes mellitus.
MedicalResearch.com: What should readers take away from your report?
Response: The most important finding is that individuals who can maintain or improve their aerobic fitness over the decade have a low risk of premature death. Therefore, it is never too late to keep up and maintain cardio-respiratory fitness or even improve fitness. We are giving very promising results and thus and middle-aged and older subjects can improve their cardio-respiratory fitness levels.
Secondly, the assessment of CRF is a simple, practical component that can be measured easily in clinical practice and directly assessed CRF is one of the strongest risk factors for mortality. It can be easily assessed also many other settings with the use of exercise testing facilities (out of hospitals, wellness centres, gyms etc.). We have also previously found that CRF is one of strongest risk factors when combined with common cardiovascular risk scores. As exercise testing with the assessment of cardio-respiratory fitness is a widely available measure, it should be used to help assess the risk in various groups of population, including patients with prior CVD, subjects with common cardiovascular risk factors and/or symptoms, and those who are very inactive but plan to become much more active.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: It is recommendable if these study findings can be repeated also in other populations. These results need to be replicated in other ethnic groups including different age groups. Also, it is useful to see whether the results are similar among those with existing cardiovascular disease such as coronary heart disease would benefit if they can maintain or improve their cardio-respiratory fitness levels, mainly due to exercise interventions and rehabilitation with standard medical therapy. Maintaining or improvement in cardio-respiratory fitness levels could be an important goal of cardiovascular disease prevention and rehabilitation.
MedicalResearch.com: Is there anything else you would like to add?
Response: This is the first study to show the value of directly assessed VO2max (other have relied just on indirect assessment of aerobic fitness) – using respiratory gases, which is a golden standard to assess cardiorespiratory fitness in a population based study. Given that strong data already exist to demonstrate that cardio-respiratory fitness is a more potent measure of health and prognosis, the inclusion of the CRF measure in the future CVD guidelines would be considered a highly valuable benefit. It is shown that, in addition to genetic component, physical exercise is an important determinant for the level of cardio-respiratory fitness. Exercise testing is still one of the most important method for assessing cardiovascular risk in clinical practice.
Cardiorespiratory fitness is a measure of cardiac and respiratory functioning. Directly measured maximal oxygen uptake (VO2max), an objective and quantitative measure of CRF, is the gold standard for assessing the amount of oxygen consumption during exercise.
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