Effects of High Intensity Interval versus Moderate Continuous Training on Markers of Ventilatory and Cardiac Efficiency in Coronary Heart Disease Patients

Background. We tested the hypothesis that high intensity interval training (HIIT) would be more effective than moderate intensity continuous training (MIT) to improve newly emerged markers of cardiorespiratory fitness in coronary heart disease (CHD) patients, as the relationship between ventilation and carbon dioxide production (VE/VCO2 slope), oxygen uptake efficiency slope (OUES), and oxygen pulse (O2P). Methods. Seventy-one patients with optimized treatment were randomly assigned into HIIT (n=23, age = 56 ± 12 years), MIT (n=24, age = 62 ± 12 years), or nonexercise control group (CG) (n=24, age = 64 ± 12 years). MIT performed 30 min of continuous aerobic exercise at 70–75% of maximal heart rate (HRmax), and HIIT performed 30 min sessions split in 2 min alternate bouts at 60%/90% HRmax (3 times/week for 16 weeks). Results. No differences among groups (before versus after) were found for VE/VCO2 slope or OUES (P>0.05). After training the O2P slope increased in HIIT (22%, P<0.05) but not in MIT (2%, P>0.05), while decreased in CG (−20%, P<0.05) becoming lower versus HIIT (P=0.03). Conclusion. HIIT was more effective than MIT for improving O2P slope in CHD patients, while VE/VCO2 slope and OUES were similarly improved by aerobic training regimens versus controls

Assessment of Cardiorespiratory Fitness without Exercise in Elderly Men with Chronic Cardiovascular and Metabolic Diseases

Low cardiorespiratory (CRF) is associated with health problems in elderly people, especially cardiovascular and metabolic disease. However, physical limitations in this population frequently preclude the application of aerobic tests. We developed a model to estimate CRF without aerobic testing in older men with chronic cardiovascular and metabolic diseases. Subjects aged from 60 to 91 years were randomly assigned into validation (n = 67) and cross-validation (n = 29) groups. A hierarchical linear regression model included age, self-reported fitness, and handgrip strength normalized to body weight (R2 = 0.79; SEE = 1.1 METs). The PRESS (predicted residual sum of squares) statistics revealed minimal shrinkage in relation to the original model and that predicted by the model and actual CRF correlated well in the cross-validation group (r = 0.85). The area under curve (AUC) values suggested a good accuracy of the model to detect disability in the validation (0.876, 95% CI: 0.793–0.959) and cross-validation groups (0.826, 95% CI: 0.677–0.975). Our findings suggest that CRF can be reliably estimated without exercise test in unhealthy elderly men

Cardiovascular responses to passive static flexibility exercises are influenced by the stretched muscle mass and the Valsalva maneuver

BACKGROUND: The respiratory pattern is often modified or even blocked during flexibility exercises, but little is known about the cardiovascular response to concomitant stretching and the Valsalva maneuver (VM) in healthy subjects. OBJECTIVES: This study evaluated the heart rate (HR), systolic blood pressure (SBP), and rate-pressure product (RPP) during and after large and small muscle group flexibility exercises performed simultaneously with the VM. METHODS: Asymptomatic volunteers (N = 22) with the following characteristics were recruited: age, 22 ± 3 years; weight, 73 ± 6 kg; height, 175 ± 5 cm; HR at rest, 66 ± 9 BPM; and SBP at rest, 113 ± 10 mmHg. They performed two exercises: four sets of passive static stretching for 30 s of the dorsi-flexion (DF) of the gastrocnemius and the hip flexion (HF) of the ischio-tibialis. The exercises were performed with (V+) or without (V-) the VM in a counterbalanced order. The SBP and HR were measured, and the RPP was calculated before the exercise session, at the end of each set, and during a 30-min post-exercise recovery period. RESULTS: The within-group comparisons showed that only the SBP and RPP increased throughout the sets (p<0.05), but no post-exercise hypotension was detected. The between-group comparisons showed that greater SBP increases were related to the VM and to a larger stretched muscle mass. Differences for a given set were identified for the HR (the HFV+ and HFV- values were higher than the DFV+ and DFV- values by approximately 12 BPM), SBP (the HFV+ value was higher than the DFV+ and DFV- values by approximately 12 to 15 mmHg), and RPP (the HFV+ value was higher than the HFV- value by approximately 2000 mmHGxBPM, and the HFV+ value was higher than the DFV+ and DFV- values by approximately 4000 mmHGxBPM). CONCLUSION: Both the stretched muscle mass and the VM influence acute cardiovascular responses to multiple-set passive stretching exercise sessions

Determination of Best Criteria to Determine Final and Initial Speeds within Ramp Exercise Testing Protocols

This study compared strategies to define final and initial speeds for designing ramp protocols. VO2max  was directly assessed in 117 subjects (29±8 yrs) and estimated by three nonexercise models: (1) Veterans Specific Activity Questionnaire (VSAQ); (2) Rating of Perceived Capacity (RPC); (3) Questionnaire of Cardiorespiratory Fitness (CRF). Thirty seven subjects (30±9 yrs) performed three additional tests with initial speeds corresponding to 50% of estimated VO2max  and 50% and 60% of measured VO2max . Significant differences (P<0.001) were found between VO2max  measured (41.5±6.6 mL·kg−1·min−1) and estimated by VSAQ (36.6±6.6 mL·kg−1·min−1) and CRF (45.0±5.3 mL·kg−1·min−1), but not RPC (41.3±6.2 mL·kg−1·min−1). The CRF had the highest ICC, the lowest SEE, and better limits of agreement with VO2max  compared to the other instruments. Initial speeds from 50%–60% VO2max  estimated by CRF or measured produced similar VO2max  (40.7±5.9; 40.0±5.6; 40.3±5.5 mL·kg−1·min−1 resp., P=0.14). The closest relationship to identity line was found in tests beginning at 50% VO2max  estimated by CRF. In conclusion, CRF was the best option to estimate VO2max  and therefore to define the final speed for ramp protocols. The measured VO2max  was independent of initial speeds, but speeds higher than 50% VO2max  produced poorer submaximal relationships between workload and VO2