Suche
reference
Hearon CM Jr, Dias KA, MacNamara JP, et al. 1 Year of HIIT and Omega-3 Fatty Acids to Improve Cardiometabolic Risk in Stage A Heart Failure.JACC heart failure. 2022;10(4):238-249.
Study objective
To determine whether one year of high-intensity interval training (HIIT) and omega-3 fatty acid supplementation would improve fitness, cardiovascular function and/or structure, and body composition in obese middle-aged adults at high risk for heart failure (Level A)
Key to take away
One year of HIIT training can produce beneficial changes in heart health biomarkers in a population of obese middle-aged individuals with biomarkers of early heart damage.
design
Prospective, randomized, attention-controlled and placebo-controlled parallel group clinical trial
Participant
The researchers assigned 80 subjects (aged 40-55 years) to either a HIIT training group or no training program as controls. Of the original 80 participants, 56 completed the experiment.
In the control group with 34 subjects, 7 discontinued participation due to time constraints or lack of follow-up examination. In the HIIT group, 17 people dropped out due to time constraints, lack of follow-up, or aversion to exercise.
The attention control group was allowed to do yoga, stretching, and strength training. Neither group received dietary interventions or guidelines.
Inclusion criteria: All subjects were between 40 and 55 years old. As defined by the American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA), they were at risk of stage A heart failure (HF). These are people at high risk of heart failure due to obesity (defined by a body mass index (BMI) of 30 or more), visceral obesity (visceral fat content >2 kg) and the increase in certain cardiac biomarkers: N-terminal pro-B-type natriuretic peptide (NT-proBNP >40 pg/ml) or high-sensitivity cardiac troponin (cTnT, >0.6 pg/ml).
There were extensive exclusion criteria, some of which appeared to limit participants' ability to participate in a HIIT program, while others suggested a stage of heart failure beyond ACCF/AHA stage “A” or suggested the possibility of a cardiac event during the program. These included: hypertension, congestive heart failure (not specified but most likely means beyond stage A), moderate to severe chronic obstructive pulmonary disease, restrictive pulmonary disease - asthma as listed in the patient population section, external angina or previous myocardial infarction, valvular heart disease, atrial fibrillation in the History, previous transient ischemic attack/stroke and treatment for obstructive sleep apnea. Participants could take antihypertension medications such as angiotensin-converting enzyme (ACE) inhibitors or diuretics, but could not use beta-blockers during the maximal exercise test.
Interventions
In the intervention group, each subject was prescribed physical training based on heart rate (HR). The goal was to increase the duration and intensity of training throughout the year. The exercise sessions, performed on a stationary bike, varied in duration (30 to 60 minutes) and intensity (continuous pace, aerobic intervals, recovery sessions). The frequency was 3 to 4 times per week. HR was recorded.
The control group was defined as those who did not participate in the HIIT activity compared to those who did so for a year. Other forms of physical activity were permitted.
WithinbothIn the control group (no HIIT) and the activity/intervention group (HIIT), there was a subgroup that received 1.6 g/day of omega-3 fatty acids and a placebo group that received 1.6 g/day of olive oil (encapsulation). So there were 4 different groups.
Evaluated study parameters
The researchers examined cardiometabolic factors and exercise outcomes as well as changes in left ventricular structure. Specifically, they examined the size of the left ventricle to determine whether cardiodilatory compensation occurred, which can lead to an increase in cardiac outputshort term.
In addition, researchers used the following as exercise outcome variables: heart rate, mean arterial blood pressure during exercise, cardiac output, stroke volume, respiratory exchange ratio, oxygen uptake (VO).2). Top VO2was defined as the highest oxygen uptake measured during a collection in the Douglas bag (holding exhaled air) for at least 30 seconds.
Structurally, they measured the following: left ventricle (LV) mass, LV volume (magnetic resonance imaging (MRI), transthoracic echocardiograph); myocardial triglyceride content (magnetic resonance spectroscopy); arterial stiffness/function (central pulsed wave velocity; augmentation index) and body composition (dual x-ray absorptiometry scan). This test used tonometry to see the reflection of wave energy - an indirect measurement of artery stiffness. The carotid arteries were also examined for stiffness using Doppler ultrasound.
Primary results
- Körperzusammensetzung
- Myokardtriglyceridkonzentration
- Maximale Trainingskapazität
- Herzumbau sowie Gefäßsteifheit und -funktion
Key findings
There was no independent or interaction effect of omega-3 fatty acid supplementation on any primary outcome variable in either group.
When comparing HIIT groups to non-HIIT groups for body composition and myocardial triglyceride concentration: There was a moderate decrease in fat mass in the exercise group (a loss of 2.63 kg;P=0.018). Loss of visceral adiposity varied, with a loss of 0.13 kg (95% CI,P=0.149).
As for myocardial triglyceride (TG) reduction, there was none. The researchers note that this result lacks statistical power because only 39 patients had interpretable pre- and post-MRI spectroscopy measurements for myocardial TG. These 39 patients were divided into 4 subgroups (HIIT plus omega-3; HIIT with placebo; control plus omega-3; control with placebo). Further studies are required to determine this parameter.
Maximum exercise capacity results: HIIT for 1 year increased absolute peak VO2(highest oxygen uptake). This was significant (95% CI,P<0.001). The researchers attributed this to an increase in peak cardiac output and stroke volume. Findings on cardiac remodeling and vascular stiffness and function: The intervention resulted in HIIT-induced cardiac remodeling (physiological) for one year, which resulted in an increase in left ventricular mass by an average of 9.40 g (95% CI,P<0.001); and increased left ventricular end-diastolic volume (better filling of the ventricle) by an average of 12.33 ml (95% CI,P<0.001). There was no effect on either arterial stiffness or carotid stiffness. There was a reduction in pulse wave augmentation index (4.81% reduction; 95% CI,P=0.009).
transparency
The American Heart Association's Strategically Focused Research Network supported the study. The authors state that there are no relationships relevant to the content of the work that need to be disclosed.
Implications and limitations for practice
This study shows very precisely the benefits of exercise in people at very high risk of heart failure/early heart failure. It is important to consider the actual study population. These were people aged 40 to 55 who were obese. They were included in this study because they had NT-proBNP elevations and/or high-sensitivity cardiac troponin. NT-proBNP is considered a valid marker of heart disease, and people with normal levels can be considered not to have heart failure.1
Brain Natriuretic Peptide (BNP) is a cardioprotective substance that counteracts the neural-hormonal effects of renin (which include overactivation of the sympathetic nervous system, increased vascular tone, and increased risk of destabilizing cardiac electrical events).2Troponin (TnT) is a biomarker of early heart damage.3Early damage can occur in various degenerative processes and progress slowly, resulting in significantly lower TnT levels than in myocardial infarction. Disconnecting, damaging forms of oxidative stress, mitochondrial fission and mitochondrial attrition are all sure signs of a rapidly aging heart and examples of a slow, degenerative process.5
This study highlights an important point: Even in patients with signs of early heart damage, there remains the ability to recondition the heart, improve oxygen utilization, physiologically remodel the heart to make it stronger, and even lose some overall fat tissue.
What's somewhat puzzling is that the HIIT program had no real impact on visceral fat. This means that a significant risk factor for cardiac death remains. The obesity and visceral fat accumulation would mean that metabolic syndrome and insulin resistance are problems for many of the study participants.
The HIIT regimen also did not reduce arterial stiffness. Contrary to what one might expect, omega-3 fatty acid supplementation did not cause a difference in arterial stiffness in either the HIIT group or the control group. The 1.6g per day is lower than the amount that could be used in a more aggressive protocol and the quality of this supplement is difficult to determine, but the zero effect is notable.
This study highlights an important point: Even in patients with signs of early heart damage, there remains the ability to recondition the heart, improve oxygen utilization, physiologically remodel the heart to make it stronger, and even lose some overall fat tissue.
This study suggests that it is not too late for middle-aged patients to increase the strength of their heart pump through proper exercise. Ultimately, it shows that they have not lost plasticity and the potential for adaptive remodeling of the heart.
Visceral fat contributes to cardiovascular risk, including heart failure. The lack of reduction in visceral fat with HIIT means that we should not expect some processes such as inflammation, lipid peroxidation and possibly dysglycemia to change with HIIT, at least not to the extent that they are related to a given patient's visceral fat.
However, exercise can also have other benefits. Exercise releases protective molecules called sestrins,from the heart. Light physical stress has a preconditioning and adaptive effect.5.6It would be interesting to observe the adaptive changes due to sestrin release that occur along with other, possibly hermetic effects during HIIT therapy.7
This study should increase our confidence in omega-3 fatty acid supplementation as a stand-alone treatment. In addition to exercise, diet can help control blood parameters associated with a higher risk of heart failure. It is clear that diet - both the elimination of lipid-boosting, pro-oxidant and glycemic regulating foods and the addition of protective, antioxidant and anti-inflammatory foods - is an essential element of a treatment plan. Diet combined with HIIT training could create a major shift away from heart failure and toward heart health.