Teaching physiology: blood pressure and heart rate changes in simulated diving

Background and Purpose: Physiology exercise employing simulated diving is used in our curriculum to integrate knowledge in cardio-respiratory physiology. Aim was to improve model used in physiology exercise by employing continuous recordings of arterial pressure and heart rate. Materials and Methods: Total of 55 medical and dental students volunteered for the exercise. They were instrumented with photoplethysmographic blood pressure and heart rate device, as well as with pulse oxymetry. Continuous measurement of variables was undertaken while students performed apneas or breathed through snorkel in air or in cold water, or temperature change was applied to their forehead. Results: Employment of continuous recordings enabled detailed insight into changes in selected cardiovascular parameters during 30 seconds breathholding. Time course of the changes showed marked biphasic response. When face was submerged in cold water during apnea, arterial pressure initially decreased and heart rate increased. At the end of breath-hold, arterial pressure increased and heart rate decreased, respectively. Corresponding changes were less pronounced when breath-hold was performed without face immersion. Conclusion: Improved protocol in laboratory exercise enabled us to show two distinct phases in changes of cardiovascular variables which are characteristic of diving reflex. We showed students how modern technology can improve their studies in near future and encouraged and motivate them to participate actively in exercise

Long-lasting exercise involvement protects against decline in V̇O2max and V̇O2 kinetics in moderately active women

We studied the effects of age on different physiological parameters, including those derived from (i) maximal cardiopulmonary exercise testing (CPET), (ii) moderate-intensity step transitions, and (iii) tensiomyography (TMG)-derived variables in moderately active women. Twenty-eight women (age, 19 to 53 years), completed 3 laboratory visits, including baseline data collection, TMG assessment, maximal oxygen uptake test via CPET, and a step-transition test from 20 W to a moderate-intensity cycling power output (PO), corresponding to oxygen uptake at 90% gas exchange threshold. During the step transitions, breath-by-breath pulmonary oxygen uptake, near infrared spectroscopy derived muscle deoxygenation (ΔHHb), and beat-by-beat cardiovascular response were continuously monitored. There were no differences observed between the young and middle-aged women in their maximal oxygen uptake and peak PO, while the maximal heart rate (HR) was 12 bpm lower in middle-aged compared with young (p = 0.016) women. Also, no differences were observed between the age groups in τ pulmonary oxygen uptake, ΔHHb, and τHR during on-transients. The first regression model showed that age did not attenuate the maximal CPET capacity in the studied population (p = 0.638), while in the second model a faster τ pulmonary oxygen uptake, combined with shorter TMG-derived contraction time (Tc) of the vastus lateralis (VL), were associated with a higher maximal oxygen uptake (∼30% of explained variance, p = 0.039). In conclusion, long lasting exercise involvement protects against a maximal oxygen uptake and τpulmonary oxygen uptake deterioration in moderately active women. Novelty: • Faster τ pulmonary oxygen uptake and shorter Tc of the VL explain 33% of the variance in superior maximal oxygen uptake attainment. • No differences between age groups were found in τ pulmonary oxygen uptake, τΔHHb, and τHR during on-transients.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Teaching physiology: blood pressure and heart rate changes in simulated diving

Background and Purpose: Physiology exercise employing simulated diving is used in our curriculum to integrate knowledge in cardio-respiratory physiology. Aim was to improve model used in physiology exercise by employing continuous recordings of arterial pressure and heart rate. Materials and Methods: Total of 55 medical and dental students volunteered for the exercise. They were instrumented with photoplethysmographic blood pressure and heart rate device, as well as with pulse oxymetry. Continuous measurement of variables was undertaken while students performed apneas or breathed through snorkel in air or in cold water, or temperature change was applied to their forehead. Results: Employment of continuous recordings enabled detailed insight into changes in selected cardiovascular parameters during 30 seconds breathholding. Time course of the changes showed marked biphasic response. When face was submerged in cold water during apnea, arterial pressure initially decreased and heart rate increased. At the end of breath-hold, arterial pressure increased and heart rate decreased, respectively. Corresponding changes were less pronounced when breath-hold was performed without face immersion. Conclusion: Improved protocol in laboratory exercise enabled us to show two distinct phases in changes of cardiovascular variables which are characteristic of diving reflex. We showed students how modern technology can improve their studies in near future and encouraged and motivate them to participate actively in exercise