The proinflammatory cytokine storm associated with coronavirus disease 2019 (COVID-19) negatively affects the hematological system, leading to coagulation activation and endothelial dysfunction and thereby increasing the risk of venous and arterial thrombosis. Coagulopathy has been reported as associated with mortality in people with COVID-19 and is partially reflected by enhanced D-dimer levels. Poor vascular health, which is associated with the cardiometabolic health conditions frequently reported in people with severer forms of COVID-19, might exacerbate the risk of coagulopathy and mortality. Sedentary lifestyles might also contribute to the development of coagulopathy, and physical activity participation has been inherently lowered due to at-home regulations established to slow the spread of this highly infectious disease. It is possible that COVID-19, coagulation, and reduced physical activity may contribute to generate a “perfect storm,” where each fuels the other and potentially increases mortality risk. Several pharmaceutical agents are being explored to treat COVID-19, but potential negative consequences are associated with their use. Exercise is known to mitigate many of the identified side effects from the pharmaceutical agents being trialled but has not yet been considered as part of management for COVID-19. From the limited available evidence in people with cardiometabolic health conditions, low- to moderate-intensity exercise might have the potential to positively influence biochemical markers of coagulopathy, whereas high-intensity exercise is likely to increase thrombotic risk. Therefore, low- to moderate-intensity exercise could be an adjuvant therapy for people with mild-to-moderate COVID-19 and reduce the risk of developing severe symptoms of illness that are associated with enhanced mortality.

Exercise has been demonstrated to have considerable effects upon haemostasis, with activation dependent upon the duration and intensity of the exercise bout. In addition, markers of coagulation and fibrinolysis have been shown to possess circadian rhythms, peaking within the morning (0600-1200 h). Therefore, the time of day in which exercise is performed may influence the activation of the coagulation and fibrinolytic systems. This study aimed to examine coagulation and fibrinolytic responses to short-duration high-intensity exercise when completed at different times of the day. Fifteen male cyclists (VO: 60.3 ± 8.1 ml kg min) completed a 4-km cycling time trial (TT) on five separate occasions at 0830, 1130, 1430, 1730 and 2030. Venous blood samples were obtained pre- and immediately post-exercise, and analysed for tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombin-anti-thrombin complexes (TAT) and D-Dimer. Exercise significantly increased plasma concentrations of TF (p < .0005), TFPI (p < .0006), TAT complexes (p < .0012) and D-Dimer (p < .0003). There was a time-of-day effect in pre-exercise TF (p = .004) and TFPI (p = .031), with 0830 greater than 1730 (p  .001), while 1730 was less than 2030 h (p = .008), respectively. There was no significant effect of time of day for TAT (p = .364) and D-Dimer (p = .228). Power output, TT time and heart rate were not significantly different between TTs (p > .05); however, percentage VO was greater at 1730 when compared to 2030 (p = .04). Due to a time-of-day effect present within TF, peaking at 0830, caution should be applied when prescribing short-duration high-intensity exercise bout within the morning in populations predisposed to hypercoagulability.

Compared with a CALRIG, the KICKR has acceptable accuracy reporting a small mean bias and narrow LoA in the measurement of power output of 250-700 W at cadences of 80-120 rpm. Caution should be applied by coaches and sports scientists when using the KICKR at power outputs of <200 W and >750 W due to the greater variability in recorded power.

This study examined physiological and perceptual responses to matched work high-intensity interval training using all-out and 2 even-paced methodologies. 15 trained male cyclists performed 3 interval sessions of three 3-min efforts with 3 min of active recovery between efforts. The initial interval session was completed using all-out pacing, with the following 2 sessions being completed with computer- and athlete-controlled pacing in a randomised and semi-counterbalanced manner. Computer- and athlete-controlled intervals were completed at the mean power from the corresponding interval during the all-out trial. Oxygen consumption and ratings of perceived exertion were recorded during each effort. 20?min following each session, participants completed a 4-km time trial and provided sessional rating of perceived exertion. Oxygen consumption was greater during all-out (54.1?6.6 ml.kg?1.min?1; p<0.01) and athlete-controlled (53.0?5.8 ml.kg?1.min?1; p<0.01) compared with computer-controlled (51.5?5.7 ml.kg?1.min?1). Total time ?85% maximal oxygen consumption was greater during all-out compared to both even-paced efforts. Sessional ratings of perceived exertion were greater after all-out compared to both even-paced sessions. Mean 4-km power output was lower after all-out compared with both even paced intervals. Distribution of pace throughout high-intensity interval training can influence perceptual and metabolic stress along with subsequent performance and should be considered during the prescription of such training.

Increasing temperature and exercise disrupt tight junctions of the gastrointestinal tract although the contribution of environmental temperature to intestinal damage when exercising is unknown. This study investigated the effect of 2 different environmental temperatures on intestinal damage when exercising at the same relative intensity. Twelve men (mean ± SD; body mass, 81.98 ± 7.95 kg; height, 182.6 ± 7.4 cm) completed randomised cycling trials (45 min, 70% maximal oxygen uptake) in 30 °C/40% relative humidity (RH) and 20 °C/40%RH. A subset of participants (n = 5) also completed a seated passive trial (30 °C/40%RH). Rectal temperature and thermal sensation (TSS) were recorded during each trial and venous blood samples collected at pre- and post-trial for the analysis of intestinal fatty acid-binding protein (I-FABP) level as a marker of intestinal damage. Oxygen uptake was similar between 30 °C and 20 °C exercise trials, as intended (p = 0.94). I-FABP increased after exercise at 30 °C (pre-exercise: 585 ± 188 pg·mL; postexercise: 954 ± 411 pg·mL) and 20 °C (pre-exercise: 571 ± 175 pg·mL; postexercise: 852 ± 317 pg·mL) (p < 0.0001) but the magnitude of damage was similar between temperatures (p = 0.58). There was no significant increase in I-FABP concentration following passive heat exposure (p = 0.59). Rectal temperature increased during exercise trials (p < 0.001), but not the passive trial (p = 0.084). TSS increased more when exercising in 30 °C compared with 20 °C (p < 0.001). There was an increase in TSS during the passive heat trial (p = 0.03). Intestinal damage, as measured by I-FABP, following exercise in the heat was similar to when exercising in a cooler environment at the same relative intensity. Passive heat exposure did not increase I-FABP. It is suggested that when exercising in conditions of compensable heat stress, the increase in intestinal damage is predominantly attributable to the exercise component, rather than environmental conditions.

The purpose of this investigation was to assess the merit of sports compression socks in minimizing travel-induced performance, physiological, and hematological alterations in elite female volleyball athletes. Twelve elite female volleyballers (age, 25 ± 2 y) travelled from Canberra (Australia) to Manila (Philippines), and were assigned to one of two conditions; compression socks (COMP, n = 6) worn during travel, or a passive control (CON, n = 6). Dependent measures included counter-movement jump (CMJ) performance, subjective ratings of well-being, cardiovascular function, calf girth, and markers of blood clotting, collected before (-24 h, CMJ;-12 h, all measures), during (+6.5 h and +9 h, subjective ratings and cardiovascular function), and after (+12 h, all measures except CMJ; + 24 h and + 48 h, CMJ) travel. As compared with CON, small-to-large effects were observed for COMP to improve heart rate (+9 h), oxygen saturation (+6.5 h and +9 h), alertness (+6.5 h), fatigue (+6.5 h), muscle soreness (+6.5 h and +9 h), and overall health (+6.5 h) during travel. After travel, smallto-moderate effects were observed for COMP to improve systolic blood pressure (+12 h), right calf girth (+12 h), and CMJ height (+24 h), mean velocity (+24 h), and relative power (+48 h), as compared with CON. COMP had no effect on markers blood clotting. This study suggests that compression socks are beneficial in combating the stressors imposed by long-haul travel in elite athletes, and may have merit for individuals frequenting long-haul travel and/or competing soon after flying.

Context: Time of day has been shown to impact athletic performance, with improved performance observed in the late afternoon–early evening. Diurnal variations in physiological factors may contribute to variations in pacing selection; however, research investigating time-of-day influence on pacing is limited. Purpose: To investigate the influence of time-of-day on pacing selection in a 4-km cycling time trial (TT). Methods: Nineteen trained male cyclists (mean [SD] age 39.0 [10.7] y, height 1.8 [0.1] m, body mass 78.0 [9.4] kg, VO2max 62.1 [8.7] mL·kg−1·min−1) completed a 4-km TT on 5 separate occasions at 08:30, 11:30, 14:30, 17:30, and 20:30. All TTs were completed in a randomized order, separated by a minimum of 2 d and maximum of 7 d. Results: No time-of-day effects were observed in pacing as demonstrated by similar power outputs over 0.5-km intervals (P = .78) or overall mean power output (333.0 [38.9], 339.8 [37.2], 335.5 [31.2], 336.7 [35.2], and 334.9 [35.7] W; P = .45) when TTs were performed at 08:30, 11:30, 14:30, 17:30, and 20:30. Preexercise tympanic temperature demonstrated a time-of-day effect (P < .001), with tympanic temperature higher at 14:30 and 17:30 than at 08:30 and 11:30. Conclusion: While a biological rhythm was present in tympanic temperature, pacing selection and performance when completing a 4-km cycling TT were not influenced by time of day. The findings suggest that well-trained cyclists can maintain a robust pacing strategy for a 4-km TT regardless of time of the day.

2022-Exercise is associated with a reduction in splanchnic blood flow that leads to the disruption of intestinal epithelium integrity, contributing to exercise-induced gastrointestinal syndrome. Strategies that promote intestinal blood flow during exercise may reduce intestinal damage, which may be advantageous for subsequent recovery and performance. This study aimed to explore if exercise-associated intestinal damage was influenced by wearing compression garments, which may improve central blood flow. Subjects were randomly allocated to wear compression socks (n 5 23) or no compression socks (control, n 5 23) during a marathon race. Blood samples were collected 24 hours before and immediately after marathon and analyzed for intestinal fatty acid-binding protein (I-FABP) concentration as a marker of intestinal damage. The magnitude of increase in postmarathon plasma I-FABP concentration was significantly greater in control group (107%; 95% confidence interval [CI], 72-428%) when compared with runners wearing compression socks (38%; 95% CI, 20-120%; p 5 0.046; d 5 0.59). Wearing compression socks during a marathon run reduced exercise-associated intestinal damage. Compression socks may prove an effective strategy to minimize the intestinal damage component of exercise-induced gastrointestinal syndrome.