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Age-Related Physiological Changes Influencing Work Ability
Published in Joanna Bugajska, Teresa Makowiec-Dąbrowska, Tomasz Kostka, Individual and Occupational Determinants, 2020
Ageing of the cardiovascular system results in decreased general performance or aerobic fitness (aerobic capacity), which is a measure of maximum oxygen absorption (VO2max). The minimal level of aerobic capacity, necessary for independent life, ranges from 13 to 14 ml O2/kg/min. Around the 25th year of age, the VO2max starts to decline by about 10% per decade (Blair et al. 1995). The decline of aerobic capacity is due to the decrease in maximum values corresponding to heart rate (HR) (approx. 6–10 beats/minute/decade) and maximum stroke volume, and a smaller increase in the maximal arteriovenous oxygen difference (AVd). The overall cardiovascular risk increases with age and depends on genetic factors, age, sex, concomitant diseases, environmental factors, lifestyle and occupational status (Sołtysik et al. 2019).
Abnormal exercise adaptation after varying severities of COVID-19: A controlled cross-sectional analysis of 392 survivors
Published in European Journal of Sport Science, 2023
Fabrício Braga, Fernanda Domecg, Marcelo Kalichsztein, Gustavo Nobre, José Kezen, Gabriel Espinosa, Christiane Prado, Marcelo Facio, Gabriel Moraes, Ilan Gottlieb, Ronaldo L. Lima, Alfred Danielian, Michael S. Emery
Two small invasive CPET (iCPET) studies have been recently published, both seeking the mechanism behind LAC in COVID-19 survivors. Baratto et al. (Baratto et al., 2021) performed iCPET the day before hospital discharge, and LAC was observed in 17/18 patients. Singh et al. (Singh et al., 2022) performed iCPET 11 months after acute COVID-19 in 10 patients (90% M-CoV), all of whom showed LAC. Both authors concluded that the primary mechanism for LAC was a lower arteriovenous oxygen difference rather than primary cardiocirculatory or ventilatory limitation. Additionally, both concluded that ventilatory maladaptation was a reduction in the PaCO2 set point and not an increase in dead space caused by pulmonary parenchymal or vascular involvement. Despite the more precise physiological assessment, iCPET may have been influenced by a potential referral bias as utilized in these studies. In conjunction with the small sample sizes, this potential bias makes extrapolation to a broader, unselected population of COVID-19 patients more difficult.
Changes in performances/characteristics of French female runners over the last 12 years
Published in Research in Sports Medicine, 2021
Lucie Lerebourg, Jeremy B. Coquart
The Top10 athletes were younger than the others in all event races. Therefore, age seems to be a factor that limits peak performance due to age-related physiological modifications. For example, although the peak performance in heterogeneous long-distance runners depends on several physiological factors (such as aerobic endurance capacity and running energy cost), the main determinant of performance is maximal oxygen uptake (Bosquet, Léger, & Legros, 2002; Di Prampero, Atchou, Brückner, & Moia, 1986). Physiologists often consider that maximal oxygen uptake is bounded by a maximal limit in arteriovenous oxygen difference, stroke volume and heart rate (Levine, 2008), and it is widely acknowledged that maximal heart rate decreases with age (Nikolaidis et al., 2018). Thus, it is logical that the Top10 athletes, who often have higher maximal oxygen uptake than other runners, were younger.
Submaximal heart rate seems inadequate to prescribe and monitor intensified training
Published in European Journal of Sport Science, 2019
Twan ten Haaf, Carl Foster, Romain Meeusen, Bart Roelands, Maria Francesca Piacentini, Selma van Staveren, Leo Koenderman, Jos J. de Koning
In line with previous work (Le Meur et al., 2014), submaximal heart rate in our study decreased both in AF and FOR athletes. Also, the correlation analyses revealed no associations between the change in heart rate and performance. This suggests that the observed change in submaximal heart rate in our study is rather a general effect of intensified training (i.e. the TFL), than that it is associated with underperformance. This can possibly be explained by the finding that, despite a decreased (sub)maximal heart rate after the TFL, ⩒O2 was unchanged at all exercise intensities. The negative association between the pre- versus post-TFL changes in heart rate and O2pulse at low and medium exercise intensity illustrates that ⩒O2 was maintained through compensation by an increased stroke volume and/or arteriovenous oxygen difference. A case study from the 1970s applied the direct Fick principle to reveal that stroke volume decreased and arteriovenous oxygen difference increased after jogging across the United States for 6 days per week, for 2.5 months (Bruce, Kusumi, Culver, & Butler, 1975). Similarly, an experimental study using impedance cardiography showed a decrease in stroke volume, and an increase in arteriovenous oxygen difference in overreached but not in acute fatigued athletes (Le Meur et al., 2014). It is, therefore, speculated that an increased arteriovenous oxygen difference compensated for the decrease in heart rate in our study, but further research in necessary to evaluate this hypothesis.