Laís Tonello

The role of physical activity and heart rate variability for the control of work related stress

Physical activity (PA) and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases (CVD). Meanwhile, heart rate variability (HRV) has been utilized to assess both stress and PA or exercise influences. The objective of the present review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge) over the last 10 years that examined these important factors. A total of seven studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise, and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

Correlates of Heart Rate Measures with Incidental Physical Activity and Cardiorespiratory Fitness in Overweight Female Workers

Previous studies have suggested that physical activity (PA) levels and cardiorespiratory fitness (CRF) impact on the autonomic control of heart rate (HR). However, previous studies evaluating PA levels did not discriminate between incidental PA and regular exercise. We hypothesized that incidental PA “per se” would influence cardiac autonomic indices as assessed via HR variability (HRV) and HR recovery (HRR) in non-exercisers. Thus, the objective of this study was to investigate the relationships between objective PA levels, CRF, and cardiac autonomic indices in adult, regular non-exercising female workers. After familiarization with procedures and evaluation of body composition, 21 women completed a submaximal cycling test and evaluation of HRR on four different days. Resting (2-min seated and standing) and ambulatory (4-h) HRV were also recorded. Levels of PA were assessed by accelerometry over five consecutive days (i.e., Wednesday to Sunday). Maximum oxygen consumption (VO2max) was measured as an index of CRF. As reliability was low to moderate for most HR measures, relationships between these and PA and CRF were examined using the 4-day average measures. Significant correlations were identified between post-exercise HRR in the first min with various PA indices (daily moderate PA, daily vigorous PA, and the sum of vigorous and very vigorous daily PA). Additionally, VO2max was significantly correlated to HRV but not to HRR. The current results indicated that CRF was influential in enhancing HRV while incidental or non-exercise based PA was associated with greater autonomic reactivation in adult overweight women. Therefore, both CRF and non-exercise based PA contribute significant but diverse effects on cardiac health. The use of 4-day averages instead of single measures for evaluation of autonomic control of HR may provide a better indication of regular cardiac autonomic function that remains to be refined.

Exercise is medicine: case report of a woman with smoldering multiple myeloma.

PURPOSE This study aimed to evaluate the influence of a supervised training program on the changes in serum monoclonal protein level (i.e., IgG), percentage of bone marrow plasma cells (BMPCs), fitness performance, and cardiac autonomic control (i.e., HR variability [HRV] and HR complexity [HRC]) in a female diagnosed with smoldering multiple myeloma (SMM). METHODS A middle-age female patient with smoldering multiple myeloma and former elite athlete was monitored for 4 yr while participating in a supervised multimodal training regimen designed for the development of various physical capacities. The patient had the possibility of self-selection of daily training volume. Changes in fitness components, IgG levels, and BMPCs were evaluated throughout a 4-yr monitoring period (i.e., follow-up). HRV was examined via 24-h HR recordings during a 6-wk period at the second and the third year of the follow-up. RESULTS Exercise performance in all fitness components was improved while IgG levels and BMPCs decreased (from 2.53 to 1.84 g · dL(-1) and from 20% to 10%, respectively). Time and frequency domain HRV parameters exhibited significant increases (18%-29%) with HRC remaining unchanged. CONCLUSIONS The current case report results indicated that a multimodal training program designed for the development of various physical capacities improved exercise performance, hematological function, and cardiac autonomic control that may improve long-term prognosis for SMM. Examination of similar exercise training regimens for hematological and other cancer populations may assist in the development of simple nonpharmacological treatments for improved prognosis.

Can Pacing Be Regulated by Post-Activation Potentiation? Insights from a Self-Paced 30 km Trial in Half-Marathon Runners

Purpose Given the co-existence of post-activation potentiation (PAP) and fatigue within muscle, it is not known whether PAP could influence performance and pacing during distance running by moderating fatigue. The aim of this study was to assess the influence of PAP on pacing, jumping and other physiological measures during a self-paced 30 km trial. Methods Eleven male endurance-trained runners (half-marathon runners) volunteered to participate in this study. Runners participated in a multi-stage 30 km trial. Before the trial started, determination of baseline blood lactate (bLa) and countermovement jump (CMJ) height was performed. The self-paced 30 km trial consisted of 6 × 5 km splits. At the end of each 5 km split (60 s break), data on time to complete the split, CMJ height, Rating of Perceived Exertion (RPE) and blood lactate were collected while heart rate was continuously monitored. Results There was a significant decrease in speed (e.g. positive pacing strategy after the 4th split, p<0.05) with a progressive increase in RPE throughout the trial. Compared with baseline, CMJ height was significantly (p<0.05) greater than baseline and was maintained until the end of the trial with an increase after the 5th split, concomitant with a significant reduction in speed and an increase in RPE. Significant correlations were found between ΔCMJ and ΔSPEED (r = 0.77 to 0.87, p<0.05) at different time points as well as between RPE and speed (r = -0.61 to -0.82, p<0.05). Conclusion Our results indicates that fatigue and potentiation co-exist during long lasting endurance events, and that the observed increase in jump performance towards the end of the trial could be reflecting a greater potentiation potentially perhaps counteracting the effects of fatigue and preventing further reductions in speed.

Influência da fadiga no equilíbrio do pé de apoio de jogadores de futebol

O objetivo do presente estudo foi investigar a influencia da fadiga no equilibrio do pe de apoio no momento do chute em jogadores de futebol. Participaram desta pesquisa 19 atletas de futebol divididos em dois grupos: grupo exaustao (GEX) que realizou um esforco com carga incremental ate a exaustao em esteira rolante, e o grupo controle (GCE) realizou um esforco leve-constante de forma continua em esteira rolante. Antes e apos os protocolos foram avaliados parâmetros de equilibrio estatico em apoio unipodal, utilizando uma plataforma de forca. O GEX apresentou aumento da area de deslocamento do centro de pressao (COP) (p < 0,05) apos exaustao, tanto para o pe direito como para o esquerdo. A velocidade maxima de deslocamento do centro de pressao ântero-posterior da perna direita do GEX aumentou significantemente (p < 0,05) apos a exaustao em relacao aos valores de repouso. A fadiga pode diminuir a capacidade de equilibrio do pe de apoio em jogadores de futebol. Principalmente no apoio com o pe que nao e o usual de apoio para o chute.