Reliability and validity of heart rate variability threshold assessment during an incremental shuttle-walk test in middle-aged and older adults

Studies on the assessment of heart rate variability threshold (HRVT) during walking are scarce. We determined the reliability and validity of HRVT assessment during the incremental shuttle walk test (ISWT) in healthy subjects. Thirty-one participants aged 57 ± 9 years (17 females) performed 3 ISWTs. During the 1st and 2nd ISWTs, instantaneous heart rate variability was calculated every 30 s and HRVT was measured. Walking velocity at HRVT in these tests (WV-HRVT1 and WV-HRVT2) was registered. During the 3rd ISWT, physiological responses were assessed. The ventilatory equivalents were used to determine ventilatory threshold (VT) and the WV at VT (WV-VT) was recorded. The difference between WV-HRVT1 and WV-HRVT2 was not statistically significant (median and interquartile range = 4.8; 4.8 to 5.4 vs 4.8; 4.2 to 5.4 km/h); the correlation between WV-HRVT1 and WV-HRVT2 was significant (r = 0.84); the intraclass correlation coefficient was high (0.92; 0.82 to 0.96), and the agreement was acceptable (-0.08 km/h; -0.92 to 0.87). The difference between WV-VT and WV-HRVT2 was not statistically significant (4.8; 4.8 to 5.4 vs 4.8; 4.2 to 5.4 km/h) and the agreement was acceptable (0.04 km/h; -1.28 to 1.36). HRVT assessment during walking is a reliable measure and permits the estimation of VT in adults. We suggest the use of the ISWT for the assessment of exercise capacity in middle-aged and older adults.

Efeitos do exercicio cronico com orientacao nutricional sobre parametros lipidicos de mulheres obesas / Effect of chronic exercise with nutritional orientation on lipidics variables at plasm from obese women

A obesidade e uma doenca com incidencia epidemiologica atinge 41,5 (por cento)da populacao brasileira e esta fortemente relacionada as dislipidemias. O objetivo do presente estudo foi observar os efeitos do exercicio cronico de intensidade moderada, realizado 2 vezes por semana durante um periodo de 12 semanas, acompanhado de orientacao nutricional, sobre a composicao lipidica no plasma de mulheres obesas. Para este estudo foram considerados os seguintes parametros: avaliacao antropometrica (peso, estatura e circunferencias da cintura e do quadril), concentracao de glicose e lipidios no soro (lipidios totais triglicerides e colesterol total, pelo metodo colorimetrico enzimatico) e avaliacao clinica nutricional. Decorrente do exercicio e da orientacao nutricional observou-se diminuicao significativa de 29,8(por cento) na concentracao de lipidios totais e de 9,50(por cento) no colesterol total (*p< 0,05), reducao media de 9,9(por cento) na concentracao de glicose sanguinea e de 18,9(por cento) na concentracao de triglicerides. Desse modo, acreditamos que este modelo de intervencao (exercicio moderado associado a orientacao nutricional) contribui de forma substancial para o controle da obesidade e alteracoes no metabolismo lipidico