Effects of long-term periodized resistance training on body composition, leptin, resistin and muscle strength in elderly post-menopausal women.

AIM: Objective of the study was to determine the effects of a periodized resistance training program on body composition, plasmatic levels of leptin and resistin, and muscle strength in elderly post-menopausal women. METHODS: Twenty-three post-menopausal women (age= 63.02±4.42 years; height 1.55±0.06 m; body mass 67.56±2.26 kg) were submitted to 12 months of periodized resistance training twice a week. The training program consisted of 3 sets of 6-14 repetitions maximal (RM). Body composition (DXA), muscle strength (bench press, leg press 45º and arm curl), plasmatic levels of resistin and leptin (ELISA method) were assessed before and after the training program. Paired Student's t test was used for comparison between pre- and post-training values. RESULTS: There was a significant increase in muscle strength and lean body mass; decrease in body mass, body fat percentage and fat mass after 12 months of resistance training, a part from the decrease in leptin and resistin levels. CONCLUSION: Long-term periodized resistance training prevents aging sarcopenia, decreases body fat and systemic markers of inflammation in postmenopausal elderly women.

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.

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.

Heart rate variability during 6-min walk test in adults aged 40 years and older.

We evaluated age- and sex-dependent differences in heart rate variability (HRV) during the 6-min walk test (6MWT) in healthy adults. We also evaluated the intensity of the 6MWT based on HRV. 78 participants aged 40-49, 50-59, 60-69, and ≥ 70 years (42 females; 36 men) performed the 6MWT. Heart rate and HRV were monitored 1 min at rest and during the last 2-min of the test. The root mean square (RMSSD), instantaneous beat-to-beat variability (SD1), and long-term standard deviation (SD2) of RR intervals were calculated. The SD1 <3 ms at the end of the 6MWT was defined as high-intensity exercise. Despite the significantly higher peak values of heart rate observed for women, we did not find sex- and age-related differences in HRV during the 6MWT. The ROC curve identified percentage of maximum heart rate >67% as the best cut-point for prediction of high-intensity exercise with 94% of sensitivity and 65% of specificity (area under the curve=0.804). We may conclude that autonomic modulation of heart rate during exercise was not dependent of age and sex. The HRV assessment during walking enables a valid estimation of exercise intensity in adults. We may therefore suggest the use of 6MWT for assessing exercise capacity and for prescribing exercises in adults aged 40 yrs and older.

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