Relationship between infection, physical and mental health and exercise habits of some Chinese residents after recovery from COVID-19.

This study aimed to determine the infection status, exercise habits, anxiety levels, and sleep quality in Chinese residents who recovered from infection during the period of coronavirus disease 2019 (COVID-19) period. It also aimed to investigate the influencing factors of recovery status and aid in improving intervention measures for COVID-19 recovery. This study is a sub-study nested within a cross-sectional investigation of infection and physical and mental health among partially recovered residents in all 34 provincial areas of China during the COVID-19 pandemic. A total of 1 013 participants (374 males and 639 females) completed the study. Cardiopulmonary endurance was significantly lower after infection than before infection (p â€‹< â€‹0.001). Women (3.92 â€‹± â€‹4.97) exhibited higher levels of anxiety than men (3.33 â€‹± â€‹4.54, p â€‹= â€‹0.015). The sleep score was significantly higher after infection (8.27 â€‹± â€‹7.05) than before infection (4.17 â€‹± â€‹4.97, p â€‹< â€‹0.001). The active and regular exercise groups exhibited significantly shorter durations of fever than the sedentary and irregular groups (p â€‹= â€‹0.033; p â€‹= â€‹0.021). Additionally, the active group demonstrated significantly fewer recovery days ([7.32 â€‹± â€‹3.24] days) than the sedentary group ([7.66 â€‹± â€‹3.06] days, p â€‹= â€‹0.035). We found a correlation between age and the recovery time of symptoms after COVID-19. We noted that a greater number of symptoms corresponded to poorer cardiopulmonary fitness and sleep quality. Individuals who engage in sedentary lifestyles and irregular exercise regimens generally require prolonged recovery periods. Therefore, incorporating moderate exercise, psychological support, sleep hygiene and other health interventions into post-COVID-19 recovery measures is imperative.

Aerobic capacity and [Formula: see text] kinetics adaptive responses to short-term high-intensity interval training and detraining in untrained females.

PURPOSE: This study investigated the physical fitness and oxygen uptake kinetics (τ[Formula: see text]) along with the O2 delivery and utilization (heart rate kinetics, τHR; deoxyhemoglobin/[Formula: see text] ratio, ∆[HHb]/[Formula: see text]) adaptations of untrained female participants responding to 4 weeks of high-intensity interval training (HIIT) and 2 weeks of detraining. METHODS: Participants were randomly assigned to HIIT (n = 11, 4 × 4 protocol) or nonexercising control (n = 9) groups. Exercising group engaged 4 weeks of treadmill HIIT followed by 2 weeks of detraining while maintaining daily activity level. Ramp-incremental (RI) tests and step-transitions to moderate-intensity exercise were performed. Aerobic capacity and performance (maximal oxygen uptake, [Formula: see text]; gas-exchange threshold, GET; power output, PO), body composition (skeletal muscle mass, SMM; body fat percentage, BF%), muscle oxygenation status (∆[HHb]), [Formula: see text], and HR kinetics were assessed. RESULTS: HIIT elicited improvements in aerobic capacity ([Formula: see text], + 0.17 ± 0.04 L/min; GET, + 0.18 ± 0.05 L/min, P < 0.01; PO-[Formula: see text], ± 23.36 ± 8.37 W; PO-GET, + 17.18 ± 3.07 W, P < 0.05), body composition (SMM, + 0.92 ± 0.17 kg; BF%, - 3.08% ± 0.58%, P < 0.001), and speed up the τ[Formula: see text] (- 8.04 ± 1.57 s, P < 0.001) significantly, extending to better ∆[HHb]/[Formula: see text] ratio (1.18 ± 0.08 to 1.05 ± 0.14). After a period of detraining, the adaptation in body composition and aerobic capacity, as well as the accelerated τ[Formula: see text] were maintained in the HIIT group, but the PO-[Formula: see text] and PO-GET declined below the post-training level (P < 0.05), whereas no changes were reported in controls (P > 0.05). Four weeks of HIIT induced widespread physiological adaptations in females, and the majority of improvements were preserved after 2 weeks of detraining except for power output corresponding to [Formula: see text] and GET.

Adaptations to 4 weeks of high-intensity interval training in healthy adults with different training backgrounds.

PURPOSE: This study investigated the physical fitness and oxygen uptake kinetics ([Formula: see text]) along with the exercise-onset O2 delivery (heart rate kinetics, τHR; changes in normalized deoxyhemoglobin/[Formula: see text] ratio, Δ[HHb]/[Formula: see text]) adaptations of individuals with different physical activity (PA) backgrounds responding to 4 weeks of high-intensity interval training (HIIT), and the possible effects of skeletal muscle mass (SMM) on training-induced adaptations. METHODS: Twenty subjects (10 high-PA level, HIIT-H; 10 moderate-PA level, HIIT-M) engaged in 4 weeks of treadmill HIIT. Ramp-incremental (RI) test and step-transitions to moderate-intensity exercise were performed. Cardiorespiratory fitness, body composition, muscle oxygenation status, VO2 and HR kinetics were assessed at baseline and post-training. RESULTS: HIIT improved fitness status for HIIT-H ([Formula: see text], + 0.26 ± 0.07 L/min; SMM, + 0.66 ± 0.70 kg; body fat, - 1.52 ± 1.93 kg; [Formula: see text], - 7.11 ± 1.05 s, p < 0.05) and HIIT-M ([Formula: see text], 0.24 ± 0.07 L/min, SMM, + 0.58 ± 0.61 kg; body fat, - 1.64 ± 1.37 kg; [Formula: see text], - 5.48 ± 1.05 s, p < 0.05) except for visceral fat area (p = 0.293) without between-group differences (p > 0.05). Oxygenated and deoxygenated hemoglobin amplitude during the RI test increased for both groups (p < 0.05) except for total hemoglobin (p = 0.179). The Δ[HHb]/[Formula: see text] overshoot was attenuated for both groups (p < 0.05) but only eliminated in HIIT-H (1.05 ± 0.14 to 0.92 ± 0.11), and no change was observed in τHR (p = 0.144). Linear mixed-effect models presented positive effects of SMM on absolute [Formula: see text] (p < 0.001) and ΔHHb (p = 0.034). CONCLUSION: Four weeks of HIIT promoted positive adaptations in physical fitness and [Formula: see text] kinetics, with the peripheral adaptations attributing to the observed improvements. The training effects are similar between groups suggesting that HIIT is effective for reaching higher physical fitness levels.