Browsing by Author "Lee, Emma"

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    Maximal Aerobic Capacity, Running Economy, and Performance in Highly Trained Marathon Runners and Master Long-Distance Runners
    (2018-11) Lee, Emma
    Maximal aerobic capacity (VO2max) and running economy (RE) are key predictors of distance-running performance. Whether VO2max and RE change with marathon-specific training in competitive sub-elite runners is unclear. While VO2max is known to decline with age, RE may be maintained in older runners. PURPOSE: The purpose of this study was to evaluate VO2max and RE at the beginning and end of a marathon training block in highly trained runners. Furthermore, master athletes training for a long-distance running event were evaluated shortly prior to their goal race to investigate relationships between age and running performance variables. Physiological and training factors were assessed to determine predictors of race performance in master runners. Several measures of RE were used. METHODS: In the study of younger competitive runners, participants were studied ~10 and 1-2 weeks before their goal marathons. They logged their workouts throughout a 12-week training period. The study on master athletes was cross-sectional. These runners were surveyed about recent and long-term training patterns. All participants completed a treadmill marathon-intensity effort (MIE) and VO2max test. RESULTS: Among the sub-elite runners, VO2max increased across the training period, while the percent of VO2max used during the MIE decreased. Race performance, quantified using a temperature-converted VDOT score, was negatively correlated with MIE allometrically scaled oxygen consumption (alloVO2). Among master runners, age was negatively associated with VO2max and alloVO2. Age was positively related to the MIE energy cost (EC) of running in females and to MIE oxygen consumption (VO2) in males. The most important predictors of converted VDOT in master runners were VO2max and three-year peak weekly training distance (3YP). Other significant predictors of VDOT were alloVO2 and EC. CONCLUSION: Experienced open-age marathon runners may experience an increase in VO2max with a block of marathon training. Age is negatively associated with VO2max and alloVO2 in fit master runners. Long-distance race performance in master athletes is positively associated with VO2max, 3YP, and alloVO2, and negatively associated with EC. Allometrically scaled MIE VO2 may therefore be a useful and performance-related measure of RE in trained runners of all ages.
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    Menopausal symptoms and sympathetic activity in post-menopausal females
    (2020-12-22) Panigrahy, Nisha; Lee, Emma; Glazos, Aline; Stokes, William; Keller-Ross, Manda
    Menopausal symptoms and sympathetic activity in post-menopausal females Nisha Panigrahy 1 , Emma Lee 1 , Aline Glazos 1 , William Stokes 1 , and Manda Keller-Ross 1,2 1 Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota 2 Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Introduction: Common symptoms of menopause include vasomotor symptoms (VMS; night sweats and hot flashes), exhaustion, depression, anxiety, and sexual dysfunction. Previous studies show that females who experience VMS may be at greater risk for hypertension (HTN) and cardiovascular disease (CVD) than those who do not have VMS. In addition, exaggerated blood pressure (BP) responses to stress, such as with a cold pressor test (CPT), can predict future HTN. However, it is unclear whether the experience of menopausal symptoms, rather than VMS specifically, contribute to HTN or CVD risk. Thus, the aim of our study was to determine if menopausal symptoms influence sympathetic reactivity to a CPT in postmenopausal females.  Methods: Six postmenopausal females (age 61±2yr) attended two study visits. The first visit included written informed consent, completion of the Menopause-Specific Quality of Life questionnaire (MENQOL), and blood draws to measure sex hormone levels. The MENQOL asked participants to rate how bothered they felt in four areas of symptoms: vasovagal (i.e., VMS), psychosocial, physical, and sexual. The absence of a symptom corresponds with a score of 1 point, whereas a present symptom is rated according to how bothersome it is and is scored from 2-8 points. Participants were classified as NSYMP (non-symptomatic) or SYMP (symptomatic) based on their MENQOL scores. The second visit began after an overnight fast. During a five-min rest and a two-min CPT of the hand, continuous noninvasive BP, heart rate via three-lead electrocardiography (ADInstruments, Colorado Springs, CO), and muscle sympathetic nerve activity (MSNA) via microneurography were measured. Results: Total MENQOL scores ranged from 1.3-2.4 on a 1-8 scale; physical symptom scores ranged from 1.1 to 2.7; and vasovagal symptoms (VMS) ranged from 1.0-1.7. Baseline MSNA incidence [bursts/100 heart beats (hb)] correlated with the MENQOL scores for physical symptoms (r=0.81, p<0.05), but not VMS (p>0.05), indicating that physical symptom severity was correlated with resting sympathetic activity. Further, baseline MSNA was greater in females who had symptoms than in asymptomatic participants (SYMP: 66±10, NSYMP: 40±9 bursts/100hb, 95% [CI: 17, 62], p = 0.03). The different MSNA responses to CPT between the SYMP and NSYMP females (time x group, p=0.04, ղ p 2 =0.79) indicated that SYMP females had a smaller increase with CPT than NSYMP, likely due to the elevated MSNA baseline in the SYMP group compared to NSYMP. Mean arterial pressure (MAP) increased similarly in both groups (time x group, p=0.44, ղ p 2 =0.16). However, greater BP and sympathetic reactivity to CPT was not observed in SYMP than in NSYMP.  Conclusion:  Females with menopausal symptoms had elevated resting sympathetic activity which was associated with severity of physical menopausal symptoms. However, in this small sample, females with menopause symptoms did not have an exaggerated BP and sympathetic reactivity to a stressor compared with females who do not experience symptoms.