Low-Volume, High-Intensity Interval Training in Patients With CAD

Katharine D. Currie; Jonathan B. Dubberley; Robert S. Mckelvie; Maureen J. Macdonald

Disclosures

Med Sci Sports Exerc. 2013;45(8):1436-1442. 

In This Article

Results

There were no differences in pretraining age, height, weight, body mass index, CAD criteria, time since CAD event, or medications between HIT and END (P ≤ 0.05). Posttraining weight decreased (END, -1.2 ± 1.8 kg; HIT, -0.6 ± 2.2 kg, P ≤ 0.05). Exercise training data for the supervised sessions are reported in Table 1. The END group performed twice as much total work and average work per supervised exercise session compared with the HIT group (P ≤ 0.01). The HIT group had higher mean heart rates during the supervised sessions than the END group. HIT trained at 73% ± 10% of their age-predicted maximal heart rate, whereas END trained at 65% ± 4%. There was no difference in exercise attendance between exercise groups. There were also no group differences in the frequency or duration of unsupervised exercise sessions (P ≥ 0.05). During the 12-wk training period, END performed 14 ± 14 unsupervised exercise sessions for 45 ± 3 min per session, whereas HIT performed 11 ± 10 unsupervised sessions for 40 ± 17 min per session. HIT trained at 68% ± 5% of their age-predicted heart rate maximum during the unsupervised sessions, which was higher than the END group, which trained at 60% ± 7% (P < 0.05).

Cardiorespiratory fitness indices are presented in Table 2. After 12 wk of training, fitness increased 19% and 24% in the END and HIT groups, respectively. Relative V·O2peak, relative V·O2 at anaerobic threshold, and PPO were significantly larger posttraining, with no differences between exercise groups. There was no change in heart rate at peak or anaerobic threshold after training or between exercise groups.

Brachial artery FMD results are reported in Figure 1. Absolute and relative FMD were increased posttraining, with no differences between exercise groups. NTG results are reported in Figure 2. Absolute and relative NTG responses were unchanged with training, with no differences between groups. Baseline brachial artery diameters for the FMD and NTG tests, time to peak dilation, and FMD peak reactive hyperemic blood flows and AUC are reported in Table 3. There was no difference in preocclusion FMD diameters and pre-NTG diameters between exercise groups, and diameters were unchanged posttraining. Preocclusion FMD diameters were also not significantly different from the pre-NTG diameters at pre- and posttraining, suggesting the artery had returned to a baseline state before the administration of NTG. Time to peak dilation during the FMD and NTG assessments were unchanged with training, with no differences between exercise groups. Peak dilation during the FMD test occurred around 1 min after cuff release, whereas maximal NTG-mediated diameters were observed between 7 and 8 min after administration. Peak reactive hyperemic blood flows and shear rate AUC were unchanged with training, with no differences between groups. Resting hemodynamics are also presented in Table 3. There was a training effect for seated brachial diastolic blood pressure and resting heart rate, with no differences between groups. Seated brachial systolic blood pressure was unchanged with training.

Figure 1.

Absolute (A) and relative (B) brachial artery flow-mediated dilation (FMD) responses pretraining (white) and posttraining (gray) for END (moderate-intensity endurance exercise) and HIT (low-volume high-intensity interval exercise) groups. *P ≤ 0.001 versus pretraining.

Figure 2.

Absolute (A) and relative (B) brachial artery nitroglycerin (NTG)-mediated dilation responses pretraining (white) and posttraining (gray) for END (moderate-intensity endurance exercise) and HIT (lowvolume high-intensity interval exercise) groups.

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