BLOOD PRESSURE RESPONSE TO RESISTANCE EXERCISE TRAINING DURING HEMODIALYSIS
Pedro Recalde, MS; Tiffany Shubert, PT, MS; Kirsten Johansen, MD; Patricia Painter, PhD
We explored the effect of lower-body isotonic exercise training on blood pressure responses in patients with end-stage renal disease (ESRD) during hemodialysis (HD). This microanalysis is part of a larger study concerning potential benefits of resistance exercise training during hemodialysis. Twenty ESRD patients, from the Renal Unit-San Francisco General Hospital, University of California, were randomized to an exercise or nonexercise group. Ninety percent of the patients were hypertensive, 55% were diabetic, 15% had COPD, and 45% had known coronary artery disease. The exercise group engaged in isotonic exercises ranging from 50% to 85% of their 3-repetition maximal (3RM) test during dialysis treatments for 12 weeks. Blood pressure and administration of hypertonic saline for blood pressure support during treatment were evaluated. Subjects completed 92% of assigned exercise sessions. The control group (mean age 51.9 +/- 14.4 years, height 165 +/- 9.4 cm, weight 66.25 +/- 14.7 kg) began dialysis sessions with an average blood pressure of 145.6 +/- 15.2 mm/Hg and dropped to 131.2 +/- 15.9 mm/Hg during the course of the HD session. The exercise group (mean age 51.2 +/- 15.1 years, height 159.3 +/- 11.2 cm, weight 60.7 +/- 19.1 kg) experienced a slightly greater (but not statistically significant, P = .99) decrease in blood pressure, from 144.5 +/- 15.1 mm/Hg to 125.8 +/- 15.9 mm/Hg. Administration of hypertonic saline solution for blood pressure stabilization was not significantly different between the groups (5.4 vs 5.9, P = .88). These data indicate that resistance training at 50% to 80% of a 3RM is safe and feasible in a group of dialysis patients with a high burden of cardiovascular disease and other comorbid conditions. The potential benefit of exercising a captive audience, resulting in increased lower body strength, and a potential increased capacity for aerobic exercise, outweighs the risk of hypo- or hypertensive episodes during dialysis.
EFFECTS OF A BETA-BLOCKER ON THE DIURNAL VARIATION OF THE HEART RATE RESERVE IN CORONARY HEART DISEASE PATIENTS
Pierre Boulay*; Monique H. Dufour*+; Denis Prud'homme++; *School of Kinesiology and Recreology, University of Moncton, Canada; +Division of Kinesiology, Laval University, Canada; ++School of Human Kinetics, University of Ottawa, Canada.
Previous studies have demonstrated that beta-blockers have an effect on the diurnal variation of the maximal heart rate attained during a morning and afternoon maximal exercise test (maxET). Accordingly, this may have an effect on the exercise target heart rate (THR). Thus, the purpose of this study was to investigate the diurnal variation in exercise THR using the heart rate reserve (HRR) method in coronary heart disease (CHD) patients treated with a beta-blocker. The exercise intensity used in this study ranged from 50% to 70% of HRR. Twenty-one CHD patients (8 women and 13 men) aged 59.9 +/- 8.9 years (mean +/- SD) who were part of a cardiac rehabilitation program participated in this study. There were 12 patients treated with metoprolol (87.5 +/- 37.7 mg twice daily) and 9 with atenolol (72.2 +/- 34.1 mg daily). All subjects were randomly submitted, on two different days, to an indirect maxET (Bruce protocol) 2 to 3 hours and 8 to 10 hours after their morning medication intake. No significant differences in exercise capacity (8.6 +/- 1.9 vs 8.5 +/- 2.0 METs; NS) and rate of perceived exertion (7.3 +/- 1.6 vs 7.1+/-1.3; NS) were observed between the morning and afternoon maxET, respectively. However, maximal heart rate (112.2 +/- 18.3 vs 127.4+/-21.1 bpm;P < .01) was significantly lower in the morning. Accordingly, exercise training THR were significantly lower in the morning (85.4 +/- 11.8 to 96.2 +/- 13.8 bpm) than the afternoon (94.6 +/- 14 to 107.7 +/- 16.7 bpm;P < .001). Furthermore, exercise heart rate at 70% of the HRR (96 bpm) according to the morning maxET corresponded to approximately 50% of the HRR (95 bpm) from the afternoon maxET. Thus, the time of day of maxET and the exercise sessions should be taken into consideration for the exercise prescription. In fact, a modification of +/-10% in exercise THR reduced the diurnal variation effect of a morning or afternoon maximal exercise test.
THE 6-MINUTE WALK TEST: HOW IMPORTANT IS THE LEARNING EFFECT?
Grace Y. Wu; Bonnie K. Sanderson; Vera Bittner; University of Alabama at Birmingham
Rationale:
The 6-minute walk test (6MWT) is a submaximal exercise test that is widely used as an outcomes measure in clinical trials and cardiopulmonary rehabilitation. An initial learning effect with repeated administration is well documented, but it is unknown whether this learning effect persists over time.
Objective:
This study was designed to determine whether the learning effect persists after 2 months.
Methods:
Fifty healthy adult volunteers (mean age 30.6 years, 48% men, 82% white) unfamiliar with the 6MWT completed 3 walks at baseline (walks 1-3) and 3 walks at follow-up (walks 4-6). Height, weight, and self-reported physical activity were assessed at both time points. Distances walked during the 6 walks were compared using a general linear model for repeated measures with post-hoc pairwise comparisons corrected by the Bonferroni method;P < .05 was considered significant.
Results:
Distance walked increased significantly between walks 1 and 3 (2046 +/- 228 ft to 2194 +/- 266 ft, P < .05). There was no difference in distance walked between walks 3 and 4 conducted 2 months apart. Distance walked increased significantly between walks 4 and 6 (2201 +/- 233 ft to 2285 +/- 257 ft, P < .05) (see Figure). The overall learning effect was inversely correlated with distance walked at walk 1, but was unrelated to age, gender, height, weight, or physical activity level.
Conclusions:
We conclude that the initial learning effect is maintained over a 2-month period and that a more modest additional learning effect occurs during the follow-up walks. Both learning effects should be taken into account when using the 6MWT as an outcomes measure.
SIX-MINUTE WALK PERFORMANCE IMPROVES AFTER 6 MONTHS OF PULMONARY REHABILITATION PARTICIPATION
M. Lippard, D. Verrill, NorthEast Medical Center, Concord, NC; W. Beasley, C. Barton, Davidson College Psychology Department, Davidson, NC
Rationale:
Little is known about the long-term effects of supervised pulmonary rehabilitation (PR) on functional capacity changes in patients of multiple programs.
Objective:
To determine the effect of 24 weeks of participation in North Carolina pulmonary rehabilitation (PR) on 6-minute walk (6MW) performance.
Methods:
Fifty-two patients with pulmonary diseases (22 men, 30 women) from four hospital PR programs completed 6MW tests following standardized instructions prior to and immediately after 12 weeks and 24 weeks of supervised PR participation. Overall 6MW scores (feet) were compared at each time period with repeated measures analysis of variance. Differences in 6MW scores for entry, 12 weeks, and 24 weeks were determined by post hoc paired samples t test analysis.
Results:
Overall improvements in 6MW performance were seen at 12 weeks in men and at both 12 weeks and 24 weeks in women. Mean 6MW scores for men at 12 weeks (1437.0 +/- 371.8) were 10% greater than mean entry values (1301.1 +/- 362.4;P = .003). Six-minute walk scores at 24 weeks (1464.6 +/- 415.4) were not significantly greater than 12-week scores (P = .433). Mean 6MW scores for women at 12 weeks (1357.5 +/- 327.2) were 11% greater than mean entry values (1220.0 +/- 289.6;P = .003). Scores at 24 weeks (1439.9 +/- 323.4) were 6% greater than 12-week scores (P = .001) and 18% greater than entry values (P = .001).
Conclusions:
Significant improvements in 6MW performance were observed after 12 weeks of PR participation in men and after 12 weeks and 24 weeks participation in women. Participation in PR is recommended for at least 24 weeks to promote continued improvements in physical performance in women of PR programs. Analysis on a greater number of patients across programs over longer time periods may show further benefits of long-term PR participation.
OUTCOMES ANALYSIS IN PATIENTS WITH RESTRICTIVE LUNG DISEASE COMPLETING A PULMONARY REHABILITATION PROGRAM
Mary Jane Ruf, BSN; Judah Skolnick, MD; Josephine Mei, MD; Patricia Cerrito, PhD; Carolyn Cunningham, MS, ARNP, CS; Betty Greaver, BSN; Linda Shelburne, PT
Rationale:
Most of the literature on pulmonary rehabilitation (PR) involves patients with chronic obstructive lung disease. There is very little information available about patients with restrictive lung disease.
Objectives:
This study was performed to evaluate the outcomes data for patients with restrictive lung disease completing a PR program.
Methods:
Twenty-four patients with restrictive lung disease completed an individualized outpatient pulmonary rehabilitation program based on the AACVPR guidelines. Fifty-five outcomes parameters were evaluated. The parameters were a combination of physiological, physical, and quality of life measurements. Data was collected at entry into and exit from the program. All data was subjected to statistical analysis.
Results:
Twenty-six outcomes demonstrated statistically significant improvement from entry to exit. No outcomes showed worsening. A subgroup of 14 outcomes were considered to be clinically significant (see Table).
Conclusion:
Pulmonary rehabilitation offers objective benefit to patients with restrictive lung disease. These individuals may have physiological and quality improvements in daily living as a result of a comprehensive pulmonary rehabilitation program.