The Relationship Between Heart Rate Variability, Depression, And Fatigue In Persons With Multiple Sclerosis

Abstract

Resistance exercise alone or in conjunction with caffeine increases heart rate and blood pressure in resistance-trained women. While acute resistance exercise has been shown to increase measures of left ventricular workload, the addition of caffeine on these responses is unknown. PURPOSE: To evaluate alterations in left ventricular workload at rest, following acute caffeine supplementation or placebo, as well as during recovery from a fatiguing bout of resistance exercise in resistance-trained women. METHODS: Eleven resistance-trained women (Mean±SD: Age: 24 ± 4yrs) participated in a counterbalanced, double blind, placebo-controlled, crossover-design study. Each participant drank 4mg/kg of caffeine mixed with water. Applanation tonometry was used to measure left ventricular workload at rest (Rest1), 45 minutes after caffeine ingestion (Rest2), immediately postresistance exercise (Post 1), and 10 minutes post-resistance exercise (Post2). The acute bout of resistance exercise consisted of two sets at 75% 1-repetition maximum (1RM) for 10 repetitions, and one set at 70%1RM with repetitions to failure on the squat and bench press. Two minutes of rest were given between sets and exercises. A 2x4 two-way analysis of variance (ANOVA) was used to assess the effects of condition with a repeated measure of time. RESULTS: There were significant main effects of time for wasted left ventricular energy (Rest1