Chronological distribution of readings in ambulatory blood pressure monitoring exams affects the nighttime average and the magnitude of blood pressure dipping.

STUDY OBJECTIVES: Averaged nighttime blood pressure (BP) is superior to daytime BP for cardiovascular risk stratification, and the relative change between daytime/nighttime BP (dipping%) significantly predicts cardiovascular risk. Newer reports suggest that 4 measurements at night may be enough for cardiovascular risk stratification. Since BP oscillates across the night, the temporal distribution of measurements across the night may impact nighttime BP and dipping%. Therefore, we compared average nighttime BP and dipping% when using measurements in the first half (1st-half), second (2nd-half), and a combination of both (combined). METHODS: Forty-three (17 females and twenty-six males) midlife adults aged 50±10 years old wore an ambulatory BP monitor for 24 hours at home, programmed to measure BP every 20 minutes when scheduled for daytime and every 30 minutes during a self-selected 8-hour nighttime for time-in-bed. We compared the nighttime BP averages and dipping% when using either the first four measurements from the 1st-half or 2nd-half of the nighttime and combined. RESULTS: Nighttime Systolic BP was significantly different across 1st-half, 2nd-half, and combined (111±9 vs.107±11 vs. 109±9 mmHg, p<0.01), respectively, with significant pairwise differences across all categories (p<0.01 for each). Systolic BP dipping% was significantly different across 1st-half, 2nd-half, and combined (9.9±5.5 vs.13.5±6.4 vs. 11.7±5.0 %, p<0.01), respectively, with significant pairwise differences across all categories (p<0.01 for each. Diastolic BP and diastolic dipping% were similar across the three different bins. CONCLUSION: In midlife adults, systolic nighttime BP and dipping% may depend upon when BP measurements are taken during the night.

Can blood pressure decrease after maximal exercise test predict the blood pressure lowering effect of aerobic training in treated hypertensive men?

The acute decrease in blood pressure (BP) observed after a session of exercise (called post-exercise hypotension) has been proposed as a tool to predict the chronic reduction in BP induced by aerobic training. Therefore, this study investigated whether post-exercise hypotension observed after a maximal exercise test is associated to the BP-lowering effect of aerobic training in treated hypertensives. Thirty hypertensive men (50 ± 8 years) who were under consistent anti-hypertensive treatment underwent a maximal exercise test (15 watts/min until exhaustion), and post-exercise hypotension was determined by the difference between BP measured before and at 30 min after the test. Subsequently, the patients underwent 10 weeks of aerobic training (3 times/week, 45 min/session at moderate intensity), and the BP-lowering effect of training was assessed by the difference in BP measured before and after the training period. Pearson correlations were employed to evaluate the associations. Post-maximal exercise test hypotension was observed for systolic and mean BPs (-8 ± 6 and -2 ± 4 mmHg, all P < 0.05). Aerobic training reduced clinic systolic/diastolic BPs (-5 ± 6/-2 ± 3 mmHg, both P < 0.05) as well as awake and 24 h mean BPs (-2 ± 6 and -2 ± 5 mmHg, all P < 0.05). No significant correlation was detected between post-exercise hypotension and the BP-lowering effect of training either for clinic or ambulatory BPs (r values ranging from 0.00 to 0.32, all p > 0.05). Post-exercise hypotension assessed 30 min after a maximal exercise test cannot be used to predict the BP-lowering effect of aerobic training in treated hypertensive men.

Cardiovascular physiology and autonomic heart control principles: the use of a station rotation strategy to recall basic cardiovascular knowledge among exercise science students

Abstract Aim: Cardiovascular physiology learned by exercise science students is often quickly forgotten. We tested whether a state rotation model would help students to recall key principles of Cardiovascular Physiology (CV). Methods: Seventy-one undergraduate students enrolled in the Exercise Physiology Course at the School of Physical Education and Sport, University of São Paulo, participated in the study. The students were randomly assigned into one of 4 stations, dedicated to recalling the concepts of the heart as a pump (e.g. preload, post-load, and contractility; station 1) and hemodynamics (e.g. serial and parallel conductance; station 2) by using the educational tool. Heart rate (HR) control by sympathetic nervous system activation (station 3) and HR control by vagal activation (station 4) were assessed by quantifying HR response to the Stroop color and word test and during face immersion in cold water, respectively. To evaluate the efficacy of the intervention, we used a Socrative app to launch eight multiple-choice questions before (PRE) and after (POST) the student's station rotation. The questions were related to the basic principles of exercise physiology and its consequences on the cardiovascular system. Results: The 4-station average score (% of corrected answers) achieved after the station rotation was higher than the score achieved before (71.21%, SD 14.50 vs. 31.07%, SD 18.04; for POST and PRE, respectively p < 0.005). Considering specific stations, the lowest score of corrected answers before the rotation was observed at station 2- hemodynamics when compared with station 1-heart as a pump and station 3/4 - autonomic control (18.9%, SD 0.9 vs. 46.5, SD 24.1 and 34.8, SD 2.1 for hemodynamics, heart as a pump and autonomic control, respectively). Interestingly, after the rotation, there was a significant increase in corrected scores for all stations (33.9, SD 9.8; 80.5, SD 4.6 and 90.2, SD 2.3, for hemodynamics, heart as a pump, and autonomic control, respectively). Conclusion: Our results suggest that the use of the educational tool was effective to recall CV principles that are essential to a better understanding of the CV responses to exercise and applying the concepts in exercise testing and prescription for different populations.

Post-exercise hypotension and its hemodynamic determinants depend on the calculation approach.

Post-exercise hypotension (PEH) has been assessed by three calculation approaches: I = (post-exercise - pre-exercise), II = (post-exercise - post-control), and III = [(post-exercise - pre-exercise) - (post-control - pre-control)]. This study checked whether these calculation approaches influence PEH and its determinants. For that, 30 subjects underwent two exercise (cycling, 45 min, 50% VO2 peak) and two control (seated rest, 45 min) sessions. Systolic (SBP) and diastolic (DBP) blood pressures, cardiac output (CO), systemic vascular resistance (SVR), heart rate (HR), and stroke volume (SV) were measured pre- and post-interventions in each session. The mean value for each moment in each type of session was calculated, and responses to exercise were analyzed with each approach (I, II, and III) to evaluate the occurrence of PEH and its determinants. Systolic PEH was significant when calculated by all approaches (I = -5 ± 1, II = -11 ± 2, and III = -11 ± 2 mmHg, p < 0.05), while diastolic PEH was only significant when calculated by approaches II and III (-6 ± 1 and -6 ± 1 mmHg, respectively, p < 0.05). CO decreased significantly after the exercise when calculated by approach I, but remained unchanged with approaches II and III, while SVR increased significantly with approach I, but decreased significantly with approaches II and III. HR was unchanged after the exercise with approach I, but increased significantly with approaches II and III, while SV decreased significantly with all approaches. Thus, PEH and its hemodynamic determinants are influenced by the calculation approach, which should be considered when designing, analyzing, and comparing PEH studies.

Exercício físico e pressão arterial: efeitos, mecanismos, influências e implicações na hipertensão arterial / Physical exercise and blood pressure: effects, mechanisms, influences and impacts on hypertension

O exercício físico é recomendado no tratamento da hipertensão arterial. Agudamente, a execução do exercício promove aumento da pressão arterial (PA), mas, no período de recuperação pós-exercício, é possível evidenciar redução da PA e, principalmente, após um período de treinamento físico crônico, pode haver diminuição da PA clínica e de 24 horas dos hipertensos. Apesar desses efeitos serem conhecidos, sua magnitude e mecanismos dependem do tipo de exercício executado e de suas características. Este artigo revê os efeitos agudos e crônicos clássicos do exercício aeróbico e os efeitos mais recentemente estudados dos exercícios resistidos isométrico e dinâmico na PA, seus mecanismos e fatores de influência, ressaltando os pontos que embasam as recomendações atuais sobre o uso do exercício na hipertensão arterial. O conhecimento atual demonstra que: 1) o exercício aeróbico promove aumento da PA sistólica durante sua execução, gera hipotensão pós-exercício clinicamente relevante e reduz a PA clínica e de 24 horas após o treinamento; 2) o exercício resistido isométrico promove aumento progressivo da PA sistólica e diastólica durante sua execução, não produz hipotensão pós-exercício consistente e reduz a PA clínica após o treinamento, mas esse efeito hipotensor ocorre com um protocolo específico de exercício de handgrip; e 3) o exercício resistido dinâmico promove grande aumento da PA sistólica e diastólica durante sua execução, gera hipotensão pós-exercício cuja relevância clínica ainda precisa ser comprovada e parece diminuir a PA clínica, mas não a ambulatorial, após o treinamento. Face a esses conhecimentos, o treinamento aeróbico complementado pelo resistido dinâmico é recomendado na hipertensão

Physical exercise is recommended for hypertension treatment. Acutely, exercise execution increases blood pressure (BP), but, during the recovery period, BP decreases, and after a chronic training period, clinic and ambulatory BP may decrease in hypertensives. Despite these known effects of exercise, their magnitude and mechanisms depend on the type of exercise and its characteristics. This article reviews the classical acute and chronic effects of aerobic exercise and the more recent knowledge about isometric and dynamic resistance exercises on BP, its mechanisms and factors of influence, highlighting the aspects underlying exercise recommendations for hypertension. Current scientific knowledge shows that: 1) aerobic exercise increases systolic BP during its execution, produces a clinically significant post-exercise hypotension, and chronically decreases clinic and 24-hour BP; 2) isometric resistance exercise produces a progressive increase in systolic and diastolic BP during its execution, does not promote consistent post-exercise hypotension, and decreases clinic BP after training, but this hypotensive effect results from a specific protocol of isometric handgrip; and 3) dynamic resistance exercise produces a huge progressive increase in systolic and diastolic BP during its execution, promotes post-exercise hypotension with questionable clinical relevance, and seems to decrease clinic but not ambulatory BP after training. Based on this current knowledge, regular aerobic exercise complemented by dynamic resistance exercise is recommended for hypertension

Prescrição de caminhada não supervisionada, risco cardiovascular e aptidão física / Unsupervised walking prescription, cardiovascular risk and physical fitness

OBJETIVO: Avaliar, numa situação real de atuação prática, o efeito da prescrição individualizada de caminhada sem supervisão da prática sobre o risco cardiovascular e a aptidão física de usuários de um parque público. MÉTODOS: 186 sujeitos (62 ± 10 anos) foram orientados a caminhar pelo menos 3x/sem, por 30 min, com intensidade de 50 a 80% da frequência cardíaca de reserva e a fazer alongamentos antes e após a caminhada. A aptidão física e os fatores de risco cardiovascular foram avaliados pré e pós-intervenção. A análise dos dados foi dividida em duas fases: 1) análise na amostra total; 2) análise nos indivíduos com fatores de risco alterados. Os dados foram comparados pelo teste t pareado. RESULTADOS: Na amostra total, a aptidão física melhorou nos testes de marcha estacionária (+8,1 ± 14,5 passos, p < 0,05), impulsão vertical (+0,5 ± 2,7 cm, p < 0,05), flexibilidade lombar (+1,1 ± 4,7 cm, p < 0,05) e flexibilidade de ombro (+1,2 ± 2,1 cm, p < 0,05). Não ocorreram alterações nos fatores de risco cardiovascular, com exceção da redução da pressão arterial diastólica (-0,9 ± 6,0 mmHg, p < 0,05). Entretanto, nos subgrupos com fatores alterados, observou-se reduções significantes das pressões arteriais sistólica e diastólica (-13,3 ± 16,9 e -5,8 ± 8,3 mmHg, p < 0,05, respectivamente) nos hipertensos, da colesterolemia total (-19,5 ± 33,5 mg/dl, p < 0,05) nos hipercolesterolêmicos e da circunferência da cintura (-1,0 ± 4,7 cm, p < 0,05) e do índice cintura-quadril (-0,01 ± 0,04, p < 0,05) nos com obesidade central. CONCLUSÃO: Numa situação real de atuação, a prescrição de caminhada sem supervisão da prática foi efetiva em melhorar a aptidão física da amostra geral e em diminuir o risco cardiovascular específico dos indivíduos com fatores de risco...

OBJECTIVE: To evaluate, at a real practical condition, the effects of individualized prescription of walking without supervision of practice on cardiovascular risk and fitness in users of a public park. METHODS: One hundred, eighty six subjects (62 ± 10 years) were instructed to walk at least 3 times/week, during 30min, at an intensity of 50-80% of heart rate reserve and encouraged to realize stretching exercises before and after walking. Physical fitness and cardiovascular risk factors were evaluated pre and post-intervention. Data analyze was divided in 2 phases: 1) role sample analysis; and 2) analysis on subjects with altered cardiovascular risk factors. Data were compared by paired t test. RESULTS: Considering the whole sample, physical fitness improved in the following tests: stationary gate (8.1 ± 14.5 paces, p < 0.05), vertical jump (0.5 ± 2.7 cm, p < 0.05), lumbar flexibility (1.1 ± 4.7 cm, p < 0.05) and shoulder flexibility (1.2 ± 2.1 cm, p < 0.05). No significant change was observed in cardiovascular risk factors, excepted by a reduction on diastolic blood pressure (-0.9 ± 6.0 mmHg, p < 0.05). On the other hand, considering the subjects with altered cardiovascular risk factors, a significant reduction was observed on systolic and diastolic blood pressures (-13.3 ± 16.9 and -5.8 ± 8.3 mmHg, p < 0.05, respectively) in hypertensive subjects, on total cholesterol (-19.5 ± 33.5 mg/dl, p < 0.05) in hypercholesterolemic subjects, and on waist circumference (-1.0 ± 4.7 cm, p < 0.05) and waist-hip index (0.01 ± 0.04, p < 0.05) in subjects with central obesity. CONCLUSION: Under real practical circumstances, the prescription of unsupervised walking was effective in improving physical fitness in general sample and in reducing the specific cardiovascular risk in subjects who have altered cardiovascular risk factors...

Efeito da prescrição de caminhada sem supervisão da prática num parque público de São Paulo / Effects of walking prescription executed without supervision in a public park of São Paulo

Este estudo objetivou avaliar o efeito da prescrição de caminhada, realizada sem supervisão da execução, na aptidão física e no risco cardiovascular de usuários de um parque público. Para tanto, 113 voluntários foram avaliados por um questionário de risco cardiovascular; medidas antropométricas, metabólicas e cardiovasculares; e testes de aptidão física. Em seguida, receberam uma prescrição individualizada de caminhada, que realizaram sem supervisão direta de um profissional e foram reavaliados entre 3 e 9 meses. Após a intervenção, 88 pessoas relataram ter seguido a prescrição. Nelas, houve redução do índice de massa corporal (-0,3 ± 1,0kg/m2, P<0,05) e da pressão arterial diastólica (-2,4 ± 8,1mmHg, P<0,05). Houve também aumento da aptidão aeróbica, potência abdominal e das flexibilidades de ombro e lombar (+10,3 ± 17,8 passadas, +1,3 ± 4,8 abdominais, +1,16 ± 2,45 cm, +1,15 ± 4,60 cm, respectivamente, P<0,05). No grupo que não seguiu as recomendações, não houve benefícios. Desta forma, foi possível concluir que a prescrição de caminhada sem supervisão da execução foi efetiva em melhorar o risco cardiovascular e a aptidão física dos usuários que seguiram as orientações.

This study aimed to evaluate the effect of walking prescription, executed without direct supervision, on physical fitness and cardiovascular risk of the users of a public park. One hundred and thirteen volunteers were evaluated by a cardiovascular risk questionnaire; anthropometric, metabolic and cardiovascular measurements, and fitness tests. Afterwards, they received an individualized prescription of walking to execute without supervision, and were reevaluated between 3 and 9 months. After the intervention, 88 subjects reported to have followed the orientations. In them, body mass index (-0.3 ± 1.0kg/m2, P <0.05) and diastolic blood pressure decreased (-2.4 ± 8.1mmHg, P<0.05). In addition, aerobic fitness, abdominal power, and shoulder and lumbar flexibilities increased (+10.3±17.8 steps, +1.3±4.8 repetitions, +1.16±2.45 cm, +1.15±4.60 cm, respectively, P<0.05). In the subjects who did not follow the recommendations, no benefit was observed. Thus, it is possible to conclude that, in a public park, the prescription of unsupervised walking was effective for improving cardiovascular risk and physical fitness in subjects who followed the orientations.