Trent. A. Hargens

Current guidelines from the U.S. Department of Health and Human Services and the World Health Organization recommend that adults aged 18–64 should accumulate at least 150 min of moderate intensity ...

Purpose: Physical activity (PA) guidelines suggest a link between PA, sedentary time, and sleep quality (SQ). Step cadence is an emerging proxy for PA intensity, with zero cadence (ZC) indicating sedentary time. No research has explored the relationship between ZC and SQ. This study examines the relationship between ZC and SC, compared to traditional PA and sedentary metrics, all measured via accelerometry. Methods: Sleep and PA was assessed in 138 adults (53 male, 85 female, age = 23.5 ± 8.0 year.) via accelerometry. Sedentary, light, moderate, vigorous intensity PA, and ZC minutes per day were measured. SQ variables included sleep efficiency (SE), total sleep time (TST), and minutes of awake time after sleep onset (WASO). Correlation analysis and analysis of covariance was used to assess relationships between study variables and to assess differences in PA and sedentary behavior between normal and poor sleepers. Results: Sedentary time was negatively associated with SE (r = -0.24, P < 0.05) and TST (r = -0.51, P < 0.001). ZC was negatively associated with SE (r = -0.25, P < 0.05), TST (r = -0.39, P < 0.001) and positively associated with WASO (r = 0.17, P < 0.001). Poor sleepers accumulated greater ZC minutes than normal sleepers when categorized by SE (555.9 ± 69.1 vs. 521.6 ± 83.7, P = 0.02)) or TST (570.4 ± 77.7 vs. 524.5 ± 76.7, P < 0.01). Conclusion: Results suggest that zero cadence minutes is a viable metric for assessing sedentary time and may be of greater utility to more traditional measure of sedentary time.

The heart rate variability threshold (HRVT) is a clinical parameter used to gain insight into autonomic balance. Prior validation of the HRVT has been with cycle ergometry, with no studies examining the viability of treadmill exercise. The purpose of this study was to examine the reliability of the HRVT during treadmill exercise, and to compare the HRVT to the ventilatory threshold (VT). Ten healthy, college‐aged males completed two maximal graded exercise tests on a treadmill. A Polar RS800CX watch was used for heart rate and HRVT data. The HRVT was determined from three HRV variables including the root mean square of successive differences of continuous R−R intervals (RMSSD), the standard deviation of normal R−R intervals (SDNN) and the standard deviation of instantaneous beat intervals (SD1). A metabolic cart was utilized to determine the VT. Results showed no difference between the HRVT (2.4 ± 0.6 and 2.2 ± 0.3 for RMSSD, 2.8 ± 0.5 and 2.7 ± 0.5 for SDNN and 2.4 ± 0.6 and 2.3 ± 0.6 for SD1) or the VT (3.0 ± 0.3 and 3.1 ± 0.3) between trials. When compared to the VT, averaged HRVT values for RMSSD (2.3 ± 0.3) and SD1 (2.3 ± 0.5) were lower than averaged VT (2.8 ± 0.4, p < 0.05). The averaged HRVT from SDNN (2.8 ± 0.5) did not differ from the VT. These results suggest that treadmill is a viable mode for HRVT determination, and that HRVT determined by SDNN may be a better comparison to the VT.

Background: The Clinical Exercise Physiology Association first conducted a clinical exercise physiology practice survey in 2010, with a goal to repeat it every 5 y. The purpose of this survey was to collect updated data on employment, including salary, scope of work, patient population, and job responsibilities among practicing clinical exercise physiologists (CEP). Methods: The 2020 survey was disseminated by email and through social media to attract a wide range of individuals who reported working as a CEP. Results: In total, data from 776 individuals who responded to the survey were analyzed, which is less participants than in the 2010 and 2015 surveys. The median salary was $56,251, $7,500 higher than that of 2015. Those with a master's degree and clinical certification had higher median salaries compared with those without certification. There was a difference in median salary by sex, with women earning $7,500 less than men did. When mean hourly salary was adjusted for years of experience and academic degree, the difference by sex remained. Conclusion: Median salary for CEPs surveyed increased between 2015 and 2020. Data revealed benefits from obtaining a clinical certification and an advanced degree for greater compensation. Data also show a discrepancy in salary based on sex. It is unclear how the ongoing coronavirus pandemic affected the current survey results.

Impedance cardiography (IC) is a non-invasive method for assessing cardiovascular hemodynamics, and has been utilised during exercise, exclusively on a cycle ergometer. Mode-specific differences in cardiovascular hemodynamics during exercise have previously been identified, but the ability of IC to identify these differences has not been explored. Therefore, we examined the repeatability of cardiovascular hemodynamics within and between exercise modes on the treadmill (TM) and cycle (CY) ergometer. Twenty-one men (age = 21.4 ± 0.5 yr) performed four maximal exercise, two TM and two CY. Within each test, two, five-minute stages were completed corresponding to moderate and vigorous exercise intensities, respectively. Oxygen consumption (VO₂) was measured continuously during each test. Hemodynamic measures were obtained via IC, and included cardiac output (CO), heart rate (HR), stroke volume (SV), end diastolic volume (EDV), ejection fraction (EF), and systemic vascular resistance (SVR). Repeated measures ANOVA revealed that within TM exercise, there was a main effect for trial with HR only. There were no main effects for trial within CY exercise. Across exercise modes, there were significant main effects for mode with HR, EDV, and SVR. CY exercise resulted in a higher HR, lower SV and EDV, consistent with previous findings, utilising more criterion and invasive methods. Results suggest that hemodynamics, as assessed by IC, are repeatable within TM and CY exercise. In addition, it appears as though IC is capable of detecting mode-specific differences in hemodynamics, suggesting IC to be a useful assessment tool during exercise.

Objective: To assess changes in physical activity (PA) after a COVID-19 shutdown on a primarily residential university campus. Methods: Eighty students, faculty, and staff (FS) of a university (age: 32.2 ± 13.6 yr) who wore a consumer wearable technology (CWT) device completed an anonymous survey by inputting data for 30 days prior to- and 30 days following an academic break in 2020, in which the university transitioned to remote learning. Results: Steps decreased after spring break in all subjects (p < .001), but steps were impacted to a greater extent in students. 30-day, weekday, and weekend step averages all decreased in students (p < .001). FS were able to maintain their weekend step averages. Conclusions: PA decreased in a university community after the COVID-19 shutdown. Students, no longer active transport for campus life, saw a greater impact on their PA. These changes could have an impact on health status.

Background: Exercise has been shown to improve heart rate variability (HRV) at rest in healthy subjects. HRV response during and immediately after acute exercise in obese individuals following aerobic exercise training has not been evaluated. The purpose of this study was to examine the effect of 12 weeks of moderate intensity aerobic exercise training on HRV during acute exercise and active postexercise recovery in obese individuals. Methods: Eleven obese individuals (5 men, 6 women; body mass index = 39.2 ± 6.3 kg·m⁻²] underwent 12 weeks of exercise training at 60% of predicted VO_2max, determined via a submaximal treadmill test. Body composition was assessed with dual-energy x-ray absorptiometry. HRV was measured during the final minute in each exercise stage and in recovery and analyzed with Kubios HRV software. Results: Predicted VO_2max (baseline: 28.2 ± 3.5 mL·kg⁻¹·min⁻¹ and posttraining: 27.4 mL·kg⁻¹·min⁻¹, P > 0.05) was unchanged and body fat % decreased (46.2% ± 2.2 vs 45.5% ± 7.2, respectively). Initial stage heart rate and postexercise recovery heart rate was lower after training. The high frequency component was greater during the initial exercise stage after training. The low frequency component and the standard deviation of instantaneous beat-to-beat variability were greater during the final exercise stage after training. During cooldown, the root-mean-square of differences between adjacent RR intervals and high frequency normalized units were greater after training. Conclusion: HRV markers were improved during acute exercise stage and active recovery in obese individuals following 12 weeks of moderate intensity exercise training. These results suggest improvements in autonomic function can be seen with reductions in adiposity, independent of cardiorespiratory fitness changes in obese adults.

Purpose Sleep is essential for overall health and can impact academic performance. Prior research reports reduced sleep time in college students. Poor sleep may impact physical activity (PA) and sedentary behavior, or vice versa, but has not been examined extensively in this population. Therefore, the purpose of this study was to examine markers of sleep quality, PA, and sedentary behavior in college students using objective means. Methods A convenience sample of college students underwent body composition analysis and 7-day objective PA and sleep assessment via accelerometry. Results Among 81 college students (53 women), there was no association between total sleep time (TST) and weekly average PA. TST was negatively associated with sedentary minutes per day, sedentary bouts per day, and total time in sedentary bouts per day. Greater sedentary bouts per day and average sedentary minutes per day were seen in those with a TST < 6 h, with no difference in body composition. Further, TST was negatively associated with sedentary minutes accumulated on the subsequent day, for all 7 days. Conclusion In a primarily residential college student cohort, poor sleep is associated with sedentary behavior more than PA. These students, who require a high amount of transport PA to and from campus during the week, are compensating by sleeping more and moving less on the weekend.

Purpose Obesity and obstructive sleep apnea (OSA) are frequent comorbid conditions. The impact of OSA on objectively measured physical activity (PA), independent of obesity, is not clear. The purpose of this study is to examine the effect of OSA on PA measured via accelerometer. Methods Overweight-to-obese individuals were recruited and screened for the presence of OSA via portable diagnostic device and divided into an OSA (n = 35) and control group (n = 24). Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Body composition was assessed with dual-energy X-ray absorptiometry. Subjects wore an accelerometer (Actigraph GT3X+, Actigraph Corp., Pensacola, FL) for a minimum of 4 and maximum of 7 days, including at least one weekend day. Results There were no group differences in body mass index (BMI) or daytime sleepiness. Waist and neck circumference were higher in the OSA group. The OSA group was significantly older than the control group. The OSA group had fewer steps, moderate intensity minutes, moderate-to-vigorous minutes, number of PA bouts per day (≥ moderate intensity PA for ≥ 10 consecutive minutes), and total number of PA bouts. When adjusted for age, the PA bout data was no longer significant. Conclusion Individuals screened as likely possessing OSA were less physically active than individuals without OSA when measured through objective means. We found no group differences in daytime sleepiness, BMI, or percent fat, suggesting other mechanisms than obesity and sleepiness for this difference.