Inger-Lise Aamot

Aerobic interval training reduces blood pressure and improves myocardial function in hypertensive patients

Aims: Exercise is recommended as prevention, management, and control of all stages of hypertension. There are still controversies about the optimal training dose, frequency, and intensity. We aimed to study the effect of aerobic interval training on blood pressure and myocardial function in hypertensive patients. Methods and results: A total of 88 patients (52.0 ± 7.8 years, 39 women) with essential hypertension were randomized to aerobic interval training (AIT) (>90% of maximal heart rate, correlates to 85–90% of VO2max), isocaloric moderate intensity continuous training (MIT) (∼70% of maximal heart rate, 60% of VO2max), or a control group. Exercise was performed on a treadmill, three times per week for 12 weeks. Ambulatory 24-hour blood pressure (ABP) was the primary endpoint. Secondary endpoints included maximal oxygen uptake (VO2max), mean heart rate/24 hour, flow mediated dilatation (FMD), total peripheral resistance (TPR), and myocardial systolic and diastolic function by echocardiography. Systolic ABP was reduced by 12 mmHg (p < 0.001) in AIT and 4.5 mmHg (p = 0.05) in MIT. Diastolic ABP was reduced by 8 mmHg (p < 0.001) in AIT and 3.5 mmHg (p = 0.02) in MIT. VO2max improved by 15% (p < 0.001) in AIT and 5% (p < 0.01) in MIT. Systolic myocardial function improved in both exercise groups, diastolic function in the AIT group only. TPR reduction and increased FMD were only observed in the AIT group. Conclusions: This study indicates that the blood pressure reducing effect of exercise in essential hypertension is intensity dependent. Aerobic interval training is an effective method to lower blood pressure and improve other cardiovascular risk factors.

Aerobic interval training increases peak oxygen uptake more than usual care exercise training in myocardial infarction patients: a randomized controlled study

Objective: Exercise capacity strongly predicts survival and aerobic interval training (AIT) increases peak oxygen uptake effectively in cardiac patients. Usual care in Norway provides exercise training at the hospitals following myocardial infarction (MI), but the effect and actual intensity of these rehabilitation programmes are unknown. Design: Randomized controlled trial. Setting: Hospital cardiac rehabilitation. Subjects: One hundred and seven patients, recruited two to 12 weeks after MI, were randomized to usual care rehabilitation or treadmill AIT. Interventions: Usual care aerobic group exercise training or treadmill AIT as 4 × 4 minutes intervals at 85–95% of peak heart rate. Twice weekly exercise training for 12 weeks. Main measures: The primary outcome measure was peak oxygen uptake. Secondary outcome measures were endothelial function, blood markers of cardiovascular disease, quality of life, resting heart rate, and heart rate recovery. Results: Eighty-nine patients (74 men, 15 women, 57.4 ± 9.5 years) completed the programme. Peak oxygen uptake increased more (P = 0.002) after AIT (from 31.6 ± 5.8 to 36.2 ± 8.6 mL·kg−1·min−1, P < 0.001) than after usual care rehabilitation (from 32.2 ± 6.7 to 34.7 ± 7.9 mL·kg−1·min−1, P < 0.001). The AIT group exercised with significantly higher intensity in the intervals compared to the highest intensity in the usual care group (87.3 ± 3.9% versus 78.7 ± 7.2% of peak heart rate, respectively, P < 0.001). Both programmes increased endothelial function, serum adiponectin, and quality of life, and reduced serum ferritin and resting heart rate. High-density lipoprotein cholesterol increased only after AIT. Conclusions: AIT increased peak oxygen uptake more than the usual care rehabilitation provided to MI patients by Norwegian hospitals.

Long-term follow-up after cardiac rehabilitation: A randomized study of usual care exercise training versus aerobic interval training after myocardial infarction☆

due to discontinuedtraining.The design and methods of this randomized controlled trial havebeen prescribed in detail earlier [5]. Briefly, patients with an MI2–12 weeks ago were included and did either AIT as 4 times 4 minof treadmill walking at about 90% of individual heart rate maximum,or usual care continuous aerobic exercise for 60 min, twice weekly for12 weeks. The intensity during usual care was set to be moderate-to-high, and controlled by subjective ratings of perceived exertion.Datawascollectedat4timepoints;beforeandaftertraining,andat6and 30 months follow-up (Fig. 1). The primary outcome measure wasVO

The higher the better? Interval training intensity in coronary heart disease

OBJECTIVES Peak oxygen uptake (VO2 peak) increases more after high intensity interval training compared to isocaloric moderate exercise in patients with coronary heart disease (CHD). We assessed the impact of exercise intensity during high intensity intervals on the increase in VO2 peak. DESIGN/METHODS We included 112 patients with coronary heart disease who had participated in randomized trials of interval training consisting of four times four minutes intervals at 85-95% of heart rate maximum (HRmax) for 12 weeks. Exercise intensity was calculated for each patient using HR during the two last minutes of each interval, expressed as percentage of HRmax. We used a univariate general linear model with VO2 peak increase as the dependent variable and percentage of HRmax, age, number of exercise sessions, and baseline VO2 peak as covariates. Exercise intensity was also divided into three categories; <88%, 88-92%, and >92% of HRmax, and these categories were used as a fixed factor in the model. RESULTS VO2 peak increased by 3.9 (SD 3.1) mL kg(-1)min(-1), equal to 11.9% after 23.4 exercise sessions. Percentage of HRmax had a significant effect on increase in VO2 peak, both as a continuous (p=0.019) and categorical variable (p=0.020). The estimated marginal means and 95% confidence intervals of the increase in VO2 peak for the three intensity categories were 3.1 (2.0, 4.2), 3.6 (2.8, 4.4), and 5.2 (4.1, 6.3) for the <88%, the 88-92%, and the >92% category, respectively. CONCLUSIONS Even within the high intensity training zone, exercise intensity was an important determinant for improving VO2 peak in patients with coronary heart disease.

Letter to the EditorLong-term follow-up after cardiac rehabilitation: A randomized study of usual care exercise training versus aerobic interval training after myocardial infarction☆

due to discontinuedtraining.The design and methods of this randomized controlled trial havebeen prescribed in detail earlier [5]. Briefly, patients with an MI2–12 weeks ago were included and did either AIT as 4 times 4 minof treadmill walking at about 90% of individual heart rate maximum,or usual care continuous aerobic exercise for 60 min, twice weekly for12 weeks. The intensity during usual care was set to be moderate-to-high, and controlled by subjective ratings of perceived exertion.Datawascollectedat4timepoints;beforeandaftertraining,andat6and 30 months follow-up (Fig. 1). The primary outcome measure wasVO

Home-based versus hospital-based high-intensity interval training in cardiac rehabilitation: a randomized study

Background High-intensity interval training (HIT) as exercise therapy is gradually implemented in cardiac rehabilitation as the cardiovascular benefits from exercise is intensity dependent. However, in previous studies, HIT has been performed with strict supervision. The aim of the study was to assess the feasibility and effectiveness of different modes of HIT in cardiac rehabilitation. Design a randomized clinical study. Methods Ninety participants with coronary artery disease (80 men/10 women, mean age 57 ± 8 years) were randomly assigned to one of three exercise modes: group exercise (GE), treadmill exercise (TE), or home-based exercise (HE). HIT was performed twice a week for 12 weeks with an exercise intensity of 85–95% of peak heart rate. The primary outcome measure was change in peak oxygen uptake (peak VO2). Results Eighty-three participants (92%) completed the intervention without any severe adverse events. Peak VO2 increased from 34.7 ± 7.3 to 39.0 ± 8.0 ml/kg/min, 32.7 ± 6.5 to 36.0 ± 6.2 ml/kg/min, and 34.4 ± 4.8 to 37.2 ± 5.2 ml/kg/min in TE, GE, and HE, respectively. Mean group difference for TE vs. HE was 1.6 ml/kg/min (95% confidence interval, CI, 0.7 to 3.1, p = 0.02), TE vs. GE 1.1 ml/kg/min (95% CI−0.5 to 2.5, p = 0.27), and GE vs. HE 0.6 ml/kg/min (95% CI −1.0 to 2.1, p = 1). However, on-treatment analysis showed no significant difference between groups. Conclusion HIT was efficiently performed in three settings of cardiac rehabilitation, with respect to target exercise intensity, exercise attendance, and increase in peak VO2. Exercise mode was not essential for exercise capacity.

Aerobic interval training compensates age related decline in cardiac function

Objectives. To study the effect of aerobic interval training (AIT) on myocardial function in sedentary seniors compared to master athletes (MA) and young controls. Design. Sixteen seniors (72± 1 years, 10 men) performed AIT (4 × 4 minutes) at ∼90% of maximal heart rate three times per week for 12 weeks. Results were compared with 11 male MA (74± 2 years) and 10 young males (23±2 years). Results. Seniors had an impaired diastolic function compared to the young at rest. AIT improved resting diastolic parameters, increased E/A ratio (44%, p <0.01), early diastolic tissue Doppler velocity (e′) (11%, p <0.05) and e′ during exercise (11%, p <0.01), shortened isovolumic relaxation rate (IVRT) (13%, p <0.01). Left ventricle (LV) systolic function (S′) was unaffected at rest, whereas S′ during stress echo increased by 29% (p <0.01). Right ventricle (RV) S′ and RV fractional area change (RFAC) increased (9%, p <0.01, 12%, p =0.01, respectively), but not RV e′. MA had the highest end-diastolic volume, stroke volume, diastolic reserve and RV S′. Conclusion. AIT partly reversed the impaired age related diastolic function in healthy seniors at rest, improved LV diastolic and systolic function during exercise as well as RV S′ at rest.

High Intensity Interval Training for Maximizing Health Outcomes

Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT.

Long-term Exercise Adherence After High-intensity Interval Training in Cardiac Rehabilitation: A Randomized Study.

BACKGROUND AND PURPOSE Exercise adherence in general is reported to be problematic after cardiac rehabilitation. Additionally, vigorous exercise is associated with impaired exercise adherence. As high-intensity interval training (HIT) is frequently used as a therapy to patients with coronary artery disease in cardiac rehabilitation, the objective was to assess long-term exercise adherence following an HIT cardiac rehabilitation programme. METHODS A multicentre randomized study was carried out. Eligible participants were adults who had previously attended a 12-week HIT cardiac rehabilitation programme, as either a home-based or hospital-based HIT (treadmill exercise or group exercise). The primary outcome was change in peak oxygen uptake; secondary outcomes were self-reported and objectively measured physical activity. RESULTS Out of 83 eligible participants, 76 were available for assessment (68 men/8 women, mean age 59 (8) years) at a one-year follow-up. Peak oxygen uptake was significantly elevated above baseline values, (treadmill exercise: 35.8 (6.4) vs. 37.4 (7.4) ml kg(-1)  min(-1) , group exercise: 32.7 (6.5) vs. 34.1 (5.8) ml kg(-1)  min(-1) and home-based exercise: 34.5 (4.9) vs. 36.7 (5.8) ml kg(-1)  min(-1) at baseline and follow-up, respectively), with no significant differences between groups. The majority of the participants (>90%) met the recommended daily level of 30 minutes of moderate physical activity. The home-based group showed a strong trend towards increased physical activity compared with the hospital-based groups. DISCUSSION The results from this study have shown that both home-based and hospital-based HIT in cardiac rehabilitation induce promising long-term exercise adherence, with maintenance of peak oxygen uptake significantly above baseline values at a one-year follow-up. The implication for physiotherapy practice is that HIT in cardiac rehabilitation induces satisfactory long-term exercise adherence.

High-Intensity Aerobic Interval Training for Patients 3–9 Months After Stroke. A Feasibility Study

BACKGROUND AND PURPOSE High-intensity aerobic interval training (AIT) has shown to be beneficial in patients with cardiac and pulmonary diseases. Presumably, patients with stroke also benefit from such treatment. However, the feasibility and potential efficacy of high-intensity AIT should be investigated for patients early after stroke. METHODS This was a single-group, pre-test-post-test, intervention study. The intervention consisted of a 6-week high-intensity AIT programme, performed twice a week. The AIT comprised 4 × 4-minute intervals, at 85-95% of peak heart rate, interrupted by 3-minute active breaks. Adherence to the protocol, compliance and adverse events were registered to assess feasibility. Cardiorespiratory fitness and functional outcomes were assessed before and after the intervention and at 6 and 12 weeks follow-up. RESULTS Ten men and five women (mean age 70.0 ± 7.7; range 61-85 years) with mild to moderate stroke were included, 3-9 months after onset. One patient was diagnosed with cancer during follow-up. There were three minor events, but no serious adverse events occurred. All patients accomplished all training sessions and reached the 85% intensity level, except one patient who discontinued the last session. The mean peak oxygen uptake showed no significant improvement from pre-treatment, 28.7 ± 3.8 ml kg(-1)  min(-1), to post-treatment, 29.6 ± 3.6 ml kg(-1)  min(-1), p = 0.189, whereas the mean 6-minute walk test improved from 410.7 ± 101.4 m to 461.0 ± 99.6 m, p = 0.001, and the median (interquartile range) Rivermead Motor Assessment Scale improved from 12.0 (11.0-13.0) to 13.0 (11.0-13.0) points, p = 0.100. These improvements continued after the intervention was concluded. CONCLUSIONS This study has shown that high-intensity AIT is feasible for a selected group of stroke patients. However, the training should be accomplished in line with the American College of Sports Medicine guidelines for high-risk populations to ensure safety. The participants achieved a clinically highly significant improvement in walking distance. This intervention should be tested out in a randomized controlled trial to assess if it is superior to other interventions.